Background: The effects, in terms of bias and precision, of omitting non-confounding predictive covariates from generalized linear models have been well studied, and it is known that such omission results in attenuation bias but increased precision with logistic regression. However, many epidemiologic risk analyses utilize alternative models that are not based on a linear predictor, and the effect of omitting non-confounding predictive covariates from such models has not been characterized.

Methods: We employed simulation to study the effects on risk estimation of omitting non-confounding predictive covariates from an excess relative risk (ERR) model and a general additive-multiplicative relative-risk mixture model for binary outcome data in a case-control setting. We also compared the results to the effects with ordinary logistic regression.

Results: For these commonly employed alternative relative-risk models, the bias was similar to that with logistic regression when the risk was small. More generally, the bias and standard error of the risk-parameter estimates demonstrated patterns that are similar to those with logistic regression, but with greater magnitude depending on the true value of the risk. The magnitude of bias and standard error had little relation to study size or underlying disease prevalence.

Conclusions: Prior conclusions regarding omitted covariates in logistic regression models can be qualitatively applied to the ERR and the general additive-multiplicative relative-risk mixture model without substantial change. Quantitatively, however, these alternative models may have slightly greater omitted-covariate bias, depending on the magnitude of the true risk being estimated.

Background: The association between induced abortion and birth control methods (including oral contraceptives and intrauterine devices) and breast cancer may vary among countries, due to the different usage and frequency of birth control methods and induced abortion among countries. A better understanding of this association may help in determining safer birth control methods for Chinese women.

Methods: A case-control study was conducted with a total of 794 cases and 805 controls. Standardized questionnaires were used to collect information on demographic characteristics, exposure to induced abortion, birth control methods, and other risk factors for breast cancer. Multivariate logistic regression was conducted to explore the association between birth control methods and breast cancer.

Results: Multivariate logistic regression analyses showed that having a history of medical abortions, ≥3 surgical abortions, or both medical and surgical abortions was associated with an increased risk of breast cancer in post-menopausal women (odds ratio [OR] 2.48; 95% confidence interval [CI], 1.14–5.40). Pre-menopausal women who had used intra-uterine devices (IUDs) for more than 20 years tended to have a lower breast cancer risk than other age-matched pre-menopausal women (OR 0.41; 95% CI, 0.25–0.68). Both pre-menopausal and post-menopausal women who had <20 years exposure to IUDs and those who had used two or more birth control methods (with the exception of women who used IUDs for more than 20 years) tended to have much higher breast cancer risk.

Conclusion: The relationship between induced abortion and birth control methods and breast cancer was complex, though being exposed to induced abortion and two or more birth control methods in one’s lifetime appeared to be risk factors for breast cancer in Chinese women.

Background: Limited evidence is available on the association of insulin-like growth factors (IGFs) and risk of heart failure in population-based samples. We investigated whether serum IGFs concentrations can predict mortality from heart failure.

Methods: We conducted a nested case-control study of 39,242 subjects aged 40–79 years who participated in the JACC study, a large Japanese prospective cohort study; participants provided serum samples and were followed up for 9 years. In heart failure cases and age-, sex-, community-, and year of blood withdrawal-matched controls, we measured serum concentrations of IGF-I, IGF-II, and IGF binding protein 3 (IGFBP3) and transforming growth factor (TGF-β1).

Results: During the follow-up, there were 88 heart failure deaths (44 men and 44 women). Each increment of 1 standard deviation [SD] of IGF-II (120.0 ng/mL in women and 143.7 ng/mL in men) was associated with a 47% reduced risk of mortality from heart failure; multivariable odds ratio was 0.53 (95% confidence interval [CI], 0.30–0.94, P-trend = 0.03). The multivariable odds ratio in the highest quartile of IGFBP3 serum concentrations (≥3.29 µg/mL in women and ≥3.31 µg/mL in men) compared with the lowest (<2.11 µg/mL in women and <2.56 µg/mL in men) was 0.24 (95% CI, 0.05–1.11; P-trend = 0.12). No association was found between serum concentrations of IGF-I or TGF-β1 and risk of heart failure.

Conclusions: Higher serum concentrations of IGF-II were associated with lower mortality from heart failure, which might suggest a possible role of IGF-II in the occurrence or prognosis of heart failure.

Background: In Japan, mean maternal age at first childbirth is increasing. The aim of this study was to investigate whether maternal age at the first childbirth is a risk factor for preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA).

Methods: We used the results of Japan Environment and Children’s Study (JECS) who gave birth in 2011–2014. Cases of primiparous singleton pregnancies where the subject was ≥20 years and delivered after 22 weeks were included. All subjects were categorized into five groups according to maternal age: 20–24, 25–29, 30–34, 35–39, and ≥40 years. Adjusted odds ratios (aORs) for PTB (before 37 and 34 weeks), LBW (<2,500 g and <1,500 g), and SGA were calculated using a logistic regression model, with the 20–24-year age group as reference.

Results: We analyzed 38,412 singleton primiparous pregnancies. The aORs of all outcomes increased in parallel with each maternal age group >30 years. The aORs of PTB before 37 and 34 weeks, LBW <2,500 g, LBW <1,500 g, and SGA in the 30–34-year age group were 1.39 (95% confidence interval [CI], 1.16–1.67), 2.23 (95% CI, 1.45–3.41), 1.34 (95% CI, 1.18–1.53), 2.30 (95% CI, 1.35–3.94), and 1.24 (95% CI, 1.05–1.46), respectively.

Conclusion: The present study showed that higher maternal age (>30 years) at the first childbirth was an independent risk factor for PTB, LBW, and SGA.

Background: Cholangiocarcinoma (CCA) is a common malignancy in northeastern Thailand. Over the last 4 decades, several policies have been implemented for its prevention, but there has been no update on the trends and relative survival (RS). Our aim was (a) to perform a statistical assessment of the incidence trends of CCA and project future trends, and (b) to estimate relative survival.

Methods: All cases of CCA diagnosed from 1989 through 2013 were abstracted from the Khon Kaen Cancer Registry (KKCR). A jointpoint regression model was used to estimate the annual percentage change (APC) and to project future trends. We also calculated RS.

Results: There were 11,711 cases of CCA. The incidence rate increased with an APC of 1.79% (95% confidence interval [CI], −0.2 to 3.8) from 1989 through 2002, and decreased with an APC of −6.09% (95% CI, −8.2 to −3.9) from 2002 through 2013. The projected incidence of CCA should stable over the next 10 years, albeit higher than the world rate. The respective 5-year RS for both sexes for age groups of 30–40, 41–45, 51–60, and 61–98 years was 22.3% (95% CI, 16.8–29.5), 14.3% (95% CI, 12.0–17.0), 8.6% (95% CI, 7.8–10.0), and 7.2% (95% CI, 6.4–8.0).

Conclusion: The incidence rate of CCA has decreased since 2002, representing a real decline in the risk of CCA. The incidence of CCA is projected to stabilize by 2025. The survival of patients with CCA remains poor.

Background: The cost-effectiveness of childhood obesity prevention interventions is critical for their sustained implementation. This study evaluated the cost-effectiveness of the Educació en Alimentació (EdAl) program, a school-based intervention for reducing obesity.

Methods: Total EdAl program implementation costs and per-child costs were estimated. Cost-effectiveness, defined using the incremental cost-effectiveness ratio (ICER), was estimated as the difference between the intervention and control group costs divided by the obesity-related outcome effects for boys (avoided cases of obesity, obesity prevalence, body mass index [BMI], and BMI z-score units) for each group. As a significant difference (4.39%) in the reduction of obesity prevalence between the intervention and control groups was observed for boys in the EdAl program, the data were calculated only for boys.

Results: The intervention cost was 24,246.53 € for 1,550 children (15.64 €/child/3 years) or 5.21 €/child/year. The ICERs/boy were 968.66 € to avoid one case of obesity, 3.6 € to reduce the obesity prevalence by 1%, 44.68 € to decrease BMI by one unit, and 65.16 € to reduce the BMI z-score by one unit.

Conclusions: The cost of reducing the obesity prevalence in boys by 4.39% was 5.21 €/child/year, half the cost proposed by the Spanish Health Ministry, indicating that the EdAl program is cost-effective.

Background: Simple physical fitness test can be a useful potential predictor of type 2 diabetes (T2DM). We examined the association between performances on simple physical fitness tests and the incidence of T2DM.

Methods: This longitudinal study was conducted in 21,802 nondiabetic Japanese (6,649 women) aged 20 to 92 years, who underwent all physical fitness tests at baseline (April 2001 to March 2002). From April 2001 to March 2008, physical fitness tests, including grip strength, vertical jump, single-leg balance with eyes closed, forward bending, whole-body reaction time, and supine legs-up, were performed every year. Participants had physical fitness tests at least two times during the period. T2DM was also annually determined based on fasting blood glucose, glycated hemoglobin, and self-reported diabetes during the period. Discrete-time logit models were used to examine the influence of the serial level of each physical fitness test on the incidence of T2DM.

Results: During the entire study period, 972 participants developed diabetes. Lower relative grip strength (grip strength/body weight) and single-leg balance performance were associated with a higher incidence of T2DM. For relative grip strength, as compared with the fourth quartile group, the odds ratios for other groups ranged from 1.16 to 1.56 (P for trend < 0.001). For single-leg balance, the odds ratios ranged from 1.03 to 1.49 (P for trend < 0.001).

Conclusion: The performance of a simple single-leg balance test as well as that of a grip strength test were negatively associated with the risk of T2DM among Japanese.

Background: To update the findings of relative risk associated with smoking for all-cause mortality and that for lung cancer by considering longitudinal changes in smoking status during follow-up.

Methods: Data from the JPHC study of 98,747 middle-aged Japanese adults, which started in 1990–1993, were analyzed. The information on smoking status was obtained from three questionnaire surveys (baseline, the 5th year, and the 10th year after the start of follow-up). A Poisson regression model was used to investigate the impact of smoking on mortality from all causes and lung cancer using two approaches. Model 1 used information only from baseline, while model 2 used the updated smoking status from all three surveys.

Results: During the 15-year follow-up, 10,702 all-cause deaths (including 870 lung cancer cases) were identified. We compared the results obtained from two models. The relative risks associated with former smokers versus never smokers were 1.42 (95% confidence interval [CI], 1.31–1.54) among men and 1.46 (95% CI, 1.23–1.73) among women for all-cause mortality and 2.98 (95% CI, 2.09–4.24) among men and 1.83 (95% CI, 0.92–3.64) among women for lung cancer mortality, as determined using model 2. All of these were higher than the relative risks obtained from model 1. In addition, former smokers who had quit smoking due to disease during follow-up had a higher mortality risk than continuous smokers did in this study.

Conclusions: The relative risks of all-cause mortality and mortality due to lung cancer among former smokers be higher than previously documented based on updated smoking status data from repeated surveys.

Background: Previous studies have identified poor dietary intake as a health risk affecting survivors of the 2011 Great East Japan Earthquake and Tsunami. We examined the association between different social factors (eg, living conditions and perceptions of community social capital) and dietary intakes among disaster-affected survivors.

Methods: We studied 6,724 survivors in four municipalities of Iwate Prefecture 3 years after the disaster. Social capital was assessed via four items inquiring about respondents’ perceptions of social cohesion in their communities. Good dietary intake was defined according to the following criteria: intake of staple food ≥three times a day; intake of meat, fish and shellfish eggs, or soybean products ≥twice a day; vegetable intake ≥twice a day; and intake of fruit or dairy products ≥once a day. An individual who did not meet any of these criteria was defined as having poor dietary intake. We adjusted for covariates, including socioeconomic status, marital status, and residential area.

Results: Poor dietary intake was reported by 31.6% of respondents. Poisson regression analyses revealed that the following factors were related to poor dietary intake: age <65 years (men: prevalence ratio [PR] 1.48; 95% confidence interval [CI], 1.29–1.71 and women: PR 1.55; 95% CI, 1.36–1.77), difficulties in living conditions (men: PR 1.18; 95% CI, 1.00–1.39 and women: PR 1.19; 95% CI, 1.01–1.40), and low perceptions of community social capital (women: PR 1.20; 95% CI, 1.04–1.38).

Conclusions: Our findings suggest that social capital plays a role in promoting healthy dietary intake among women in disaster-affected areas.

Background: The trend of association between overweight and high serum total cholesterol (TC) among the elderly is unclear. In addition, there is little evidence of risk of underweight for high TC. Therefore, we examined the trend of association of overweight or underweight with high TC among Japanese elderly people using nationwide population-based data.

Methods: Data of the National Survey on Circulatory Disorders and National Health and Nutrition Survey for 1980, 1990, 2000, and 2010 were used in the analysis. High TC was defined as 220 mg/dL and above. For participants aged ≥50 years, sex-specific odds ratios (ORs) of overweight or underweight compared with normal body mass index participants for high TC were calculated using a logistic regression model adjusted for age, smoking, drinking, exercise, food, and treatment of hyperlipidemia.

Results: A total of 5,014, 4,673, 5,059, and 2,105 participants enrolled in these surveys in 1980, 1990, 2000, and 2010, respectively. Although overweight was positively and significantly associated with high TC in 1980, the association has gradually weakened since (ORs in 1980 and 2010 were 2.44; 95% confidence interval [CI], 1.83–3.24 and 0.92; 95% CI, 0.66–1.27 among men and 1.43; 95% CI, 1.18–1.72 and 1.08; 95% CI, 0.81–1.44 among women, respectively). While underweight was inversely and significantly associated with high TC in 1980, the association also gradually weakened among women (ORs in 1980 and 2010 were 0.28; 95% CI, 0.12–0.60 and 0.37; 95% CI, 0.10–1.28 among men and 0.39; 95% CI, 0.26–0.57 and 0.96; 95% CI, 0.58–1.57 among women, respectively).

Conclusions: These findings provide evidence that high TC prevention efforts must expand the target to not only overweight but also to normal and underweight people.

Background: High dietary non-enzymatic antioxidant capacity (NEAC) has been inversely related to the incidence of degenerative diseases. However, few studies have investigated the validity and reproducibility of dietary NEAC estimated from a food frequency questionnaire (FFQ). We assessed the validity and reproducibility of FFQ-based dietary NEAC against a dietary record (DR).

Methods: Participants were 244 men and 253 women who completed a 28-day DR and FFQs. NEAC for each food item was estimated according to available databases of antioxidant capacity, as measured by ferric reducing-antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and total radical-trapping antioxidant parameter (TRAP). Using Spearman’s rank correlation coefficients (CCs), we assessed the validity for dietary NEACs from a 28-day DR and a FFQ, and the reproducibility for them from two FFQs administered at a 1-year interval. Additionally, joint classification and the Bland-Altman method were applied to assess agreement between the two methods.

Results: Regarding validation, deattenuated CCs for the energy-adjusted overall dietary NEACs between FFQ and DR for FRAP, ORAC, and TRAP were 0.52, 0.54, and 0.52, respectively, for all subjects. Extreme miscategorization rates by joint classification analysis were 2% for FRAP and ORAC and 1% for TRAP. Regarding reproducibility, CCs between the energy-adjusted dietary NEACs from two FFQs were 0.64 for FRAP and 0.65 for ORAC and TRAP.

Conclusion: The validity and reproducibility of dietary NEAC of total food from the FFQ were moderate. Estimations of dietary NEAC using FFQ would be useful in studying disease relationships by categorizing habitual dietary NEAC.

Background: Epidemiological evidence of dyslipidemia in Pacific Island countries is limited despite the knowledge that non-communicable diseases have a high burden in the region. We aimed to examine the prevalence and correlates of dyslipidemia among residents of Palau.

Methods: The Palau STEPwise approach to Surveillance (STEPS), which was conducted from 2011 through 2013, comprised three parts: behavioral risk factors; physical measurements; and biochemical tests, covering areas such as blood lipids. We used STEPS-generated data to perform a cross-sectional study of 2,184 randomly selected Palau residents, comprising Palauans and non-Palauans aged 25–64 years.

Results: The age-adjusted mean BMI was 29.3 kg/m² in men and 29.9 kg/m² in women; age-adjusted mean triglycerides value was 182 mg/dL in men and 166 mg/dL in women; and age-adjusted mean cholesterol was 178 mg/dL in men and 183 mg/dL in women. The prevalence of overweight/obesity (BMI ≥25 kg/m²) was 75% in men and 76% in women, and those of hypertriglyceridemia (triglycerides ≥150 mg/dL) and hypercholesterolemia (total cholesterol ≥200 mg/dL) were 48% in men and 41% in women and 18% in men and 23% in women, respectively. Mean values of total cholesterol were 177 mg/dL in Palauan men and 182 mg/dL in non-Palauan men. Mean values of triglycerides were 171 mg/dL in Palauan women and 150 mg/dL in non-Palauan women. Women living in rural areas showed a higher mean value of total cholesterol than those in urban areas.

Conclusion: We found a high mean BMI and high prevalence of overweight/obesity and hypertriglyceridemia, but low mean total cholesterol and a low prevalence of hypercholesterolemia in Palau. Lipid profiles varied by age, ethnicity, and living area.

Background: The presence of comorbidities in cancer patients may influence treatment decisions and prognoses. This study aimed to examine the impact of comorbidities on overall survival in Japanese patients diagnosed with major solid tumors.

Methods: To obtain patient-level information on clinical conditions and vital status, we performed a record linkage of population-based cancer registry data from Osaka Prefecture, Japan and administrative data produced under the Diagnosis Procedure Combination (DPC) system. The study population comprised patients who received a primary diagnosis of gastric, colorectal, or lung cancer between 2010 and 2012 at any of five cancer centers. We employed the Charlson Comorbidity Index (CCI) score to quantify the impact of comorbidities on survival. The association between CCI score and survival for each cancer site was analyzed using Cox proportional hazards regression models for all-cause mortality, after adjusting for patient sex, age at cancer diagnosis, and cancer stage.

Results: A total of 2,609 patients with a median follow-up duration of 1,372 days were analyzed. The most frequent CCI score among the patients was 0 (77.7%), followed by 2 (14.3%). After adjusting for the covariates, we detected a significant association between CCI score and all-cause mortality. The hazard ratios per one-point increase in CCI score were 1.12 (95% confidence interval [CI], 1.02–1.23), 1.20 (95% CI, 1.08–1.34), and 1.14 (95% CI, 1.04–1.24) for gastric, colorectal, and lung cancer, respectively.

Conclusions: Comorbidities have a negative prognostic impact on overall survival in cancer patients, and should be assessed as risk factors for mortality when reporting outcomes.

Background: Preventing and reducing frailty is an important challenge for Japan in the next decade, especially in metropolitan areas. We launched a community-wide intervention trial (the Ota Genki Senior Project) in 2016 to develop effective community-based strategies for frailty prevention in metropolitan areas. This report describes the study design and baseline survey.

Methods: This study is a community-wide intervention trial that integrates participatory action research into a cluster non-randomized controlled trial for adults aged 65 years or older living in Ota City, Tokyo. We allocated 3 of 18 districts to an intervention group and the other 15 to a control group. Using a mailed self-administered questionnaire, we conducted a baseline survey of 15,500 residents (8,000 and 7,500 in the intervention and control groups, respectively) from July through August 2016. In addition to socioeconomic status and lifestyle variables, we assessed frailty status (primary outcome) and physical, nutritional, and psychosocial variables (secondary outcomes). Based on the baseline findings, an intervention to improve outcomes will be implemented as participatory action research. Follow-up surveys will be conducted in the same manner as the baseline survey.

Results: A total of 11,925 questionnaires were returned (76.9% response rate; 6,105 [76.3%] and 5,820 [77.6%] in the intervention and control groups, respectively), and 11,701 were included in the analysis (mean age, 74.3 [standard deviation, 5.5] years; 48.5% were men).

Conclusions: This study is expected to contribute to development of a prototype of a community-wide frailty prevention strategy, especially in metropolitan areas in Japan. Trial registration: UMIN Clinical Trials Registry (UMIN000026515).

Background: The aim of this research is to assess the level of physical activity (PA) in relation to different socio-economic factors and to examine the effect of the recommended level of PA on the domains of quality of life (QoL) among residents of low-income housing in the metropolitan area of Kuala Lumpur, Malaysia.

Methods: This was a cross-sectional study that included 680 respondents from community housing projects. Reported PA was assessed using the Global Physical Activity Questionnaire (GPAQ) short form version 2. The SF-12v2 was administered to assess the health-related QoL (HRQoL) among the study population. Respondents were grouped into “active” and “insufficient” groups according to reported weekly PA level. One-way analysis of variance, analysis of co-variance, and multiple linear regression were used in the analysis.

Results: Overall, 17.6% (95% CI, 14.3–20.9) of the respondents did not achieve the recommended levels of PA (≥600 metabolic equivalent [MET]-minutes week⁻¹). Level of achieving recommended PA was higher among younger participants, females, members belonging to nuclear families, and in self-employed participants. The group that fulfilled recommended PA levels (active) has higher levels of QoL in all domains except physical functioning.

Conclusions: Almost one out of five low-income urban residents were physically inactive. In addition, individuals who attained recommended PA levels had better scores on some domains of HRQOL than those who did not. Our findings call for tailor-made public health interventions to improve PA levels among the general population and particularly for low-income residents.

Background: The respiratory tract of children in low-income families is more likely to be exposed to toxins, which may lead to poor lung function. The purpose of this study was to elucidate the impact of low household income on lung function among children and adolescents in Japan.

Methods: We analyzed a population-based sample of 1,224 children aged 5 to 17 years old from the Japanese Study on Stratification, Health, Income, and Neighborhood (J-SHINE). Forced expiratory volume in 1 s (FEV1) and in 6 s (FEV6) was measured. Annual household income and other potential covariates were assessed through a questionnaire. Low household income was defined as less than 3 million yen (approximately 27,000 United States dollars [USD]) per year. Multivariate regression analysis was used to adjust for potential covariates.

Results: We observed statistically significantly lower FEV1:FEV6 ratio with children in lowest-income families compared with those in highest-income families, after adjusting for child’s age and sex (coefficient = −0.082; 95% confidence interval [CI], −0.131 to −0.034). After adjusting for other covariates, including parental smoking status and parental diagnosis of asthma, a similar trend remained (coefficient = −0.054; 95% CI, −0.109 to 0.001).

Conclusions: Children in low-income families showed significantly lower lung function than those in high-income families. Prevention and early intervention are necessary to help the development of lung function among children living in low-income families.

Background: Several epidemiological studies have determined the relationship between diabetes and the incidence and/or prevalence of recently identified comorbid conditions (cancer, periodontal disease, fracture, cognitive impairment, and depression). These relationships may vary by country or race/ethnicity. We aimed to systematically review studies in this field conducted with the Japanese population because such a review in the Japanese population has never been undertaken.

Methods: We conducted systematic literature searches in PubMed and Ichushi-Web databases for studies published until December 2016. Studies comparing the incidence and/or prevalence of the comorbidities among the Japanese population were included. The studies were classified as integrated analyses, cohort studies, case-control studies, or cross-sectional studies.

Results: We identified 33 studies (cancer: 17, periodontal disease: 5, fracture: 5, cognitive impairment: 4, and depression: 2). Although several cohort studies and meta-analyses had assessed the development of cancer in diabetes, there was scant epidemiological evidence for the other conditions. Indeed, only one cohort study each had been conducted for periodontal disease, fracture, and cognitive impairment, whereas other evidence was cross-sectional, some of which was induced from baseline characteristic tables of studies designed for other purposes.

Conclusion: In Japan, there is insufficient evidence about the relationship between diabetes and the incidence/prevalence of periodontal disease, fracture, cognitive impairment, and depression. By contrast, several cohort studies and integrated analyses have been conducted for the relationship with cancer. Further studies should be undertaken to estimate the contribution of diabetes on the incidence/prevalence of comorbidities that may be specific to the Japanese population.

Background: We explored the distinct trajectories of functional decline among older adults in Japan, and evaluated whether the frequency of outings, an important indicator of social activity, predicts the identified trajectories.

Methods: We analyzed data on 2,364 adults aged 65 years or older from the Japan Aichi Gerontological Evaluation Study. Participants were initially independent and later developed functional disability during a 31-month follow-up period. We used the level of long-term care needs certified in the public health insurance system as a proxy of functional ability and linked the fully tracked data of changes in the care levels to the baseline data. A low frequency of outings was defined as leaving one’s home less than once per week at baseline. We applied a growth mixture model to identify trajectories in functional decline by sex and then examined the association between the frequency of outings and the identified trajectories using multinomial logistic regression analysis.

Results: Three distinct trajectories were identified: “slowly declining” (64.3% of men and 79.7% of women), “persistently disabled” (4.5% and 3.7%, respectively), and “rapidly declining” (31.3% and 16.6%, respectively). Men with fewer outings had 2.14 times greater odds (95% confidence interval, 1.03–4.41) of being persistently disabled. The association between outing frequency and functional decline trajectory was less clear statistically among women.

Conclusions: While the majority of older adults showed a slow functional decline, some showed persistent moderate disability. Providing more opportunities to go out or assistance in that regard may be important for preventing persistent disability, and such needs might be greater among men.

Background: Cedar pollinosis is one of the most prevalent forms of seasonal allergic reaction in Japan. Only one prospective study has examined the association between cedar pollinosis and mortality. Using a symptom-based questionnaire on cedar pollinosis, we investigated the association of cedar pollinosis with all-cause and cause-specific mortality.

Methods: Data came from the Takayama Study, which recruited residents aged ≥35 years in 1992 from Takayama city in Gifu Prefecture, Japan. The current study used information on cedar pollinosis that was obtained from the second survey in 2002. A total of 12,471 persons who were 45–80 years old and had no history of cancer, coronary heart disease, or stroke responded to a questionnaire asking about four symptoms related to cedar pollinosis. Mortality and migration data were obtained throughout the follow-up period up to March 2013. Cox proportional hazard models were used to examine the relation between cedar pollinosis and mortality.

Results: A total of 1,276 persons died during follow-up period. Among these, there were 504 neoplasm, 278 cardiovascular, and 181 respiratory deaths. After adjusting for potential confounders, cedar pollinosis was associated with significantly lower all-cause mortality (hazard ratio [HR] 0.79; 95% confidence interval [CI], 0.65–0.95) and respiratory mortality (HR 0.38; 95% CI, 0.18–0.82). There was no significant association between cedar pollinosis and mortality due to neoplasm or cardiovascular disease.

Conclusions: We found an inverse association between cedar pollinosis and the risk of all-cause and respiratory mortality. Further research is needed to elucidate the association between cedar pollinosis and mortality.

Background: Many studies have reported that oral health status is associated with various systemic health issues. This study examined the correlations among oral health, lifestyle factors, and metabolic syndrome (MetS) in aged participants.

Methods: We analyzed cross-sectional oral and medical health checkup data from 2,379 participants aged 75 and 80 years. MetS was diagnosed according to the Harmonization criteria, with the exception of the criterion for central obesity, and body mass index was used instead of waist circumference. Logistic regression analyses were performed to evaluate the correlation between oral health status and lifestyle factors and MetS in both sexes and by sex.

Results: In both sexes, the odds ratio (OR) for MetS was 1.54 (95% confidence interval [CI], 1.10–2.17) among those who had 0–9 teeth compared with those with 20–28 teeth. MetS was significantly more likely for those eating quickly than those eating slowly (OR 2.06; 95% CI, 1.35–3.16). Participants using secondary oral hygiene products every day had a significantly lower OR (0.71; 95% CI, 0.55–0.92) for MetS than did those who did not. Participants with 0–9 teeth who ate quickly had a significantly higher OR (2.48; 95% CI, 1.06–5.78) for MetS compared with those with 20–28 teeth who ate slowly.

Conclusion: These results suggest that maintaining teeth, eating slowly, and using secondary oral hygiene products every day are associated with a lower likelihood of MetS in the aged population.

Background: Although lower household economic status is known to be a risk factor for obesity among school-age children, such an association among toddlers remains unclear. The present study investigated the association between household economic status and obesity in toddlers.

Design: We conducted a cross-sectional study of children aged 4 years attending daycare centers in Japan. Information on subjective household economic status [“affluent”, “neither”, “less affluent”, or “non-affluent”] was collected via questionnaire from the children’s guardians in 2015. Based on measured values of height and weight, obesity was defined using the International Obesity Task Force cut-offs of overweight (BMI ≥17.47 for boys and ≥17.19 for girls). We used the logistic regression model to investigate the association between household economic status and obesity.

Results: Among 1,848 respondents, the prevalence of obesity was 6.8%. Non-affluent household economic status was associated with a significantly higher probability of obesity in toddlers; the multivariate adjusted odds ratio for “non-affluent” households was 2.31 (95% confidence interval, 1.23–4.33) compared with “affluent” households.

Conclusion: Perception of non-affluent economic status by the guardian was associated with a higher probability of toddler obesity. This result suggests that non-affluent household economic status is associated with obesity in toddlers.

Background: A recent meta-analysis compared the relative risks of colorectal cancer between the highest and lowest levels of coffee consumption in the Japanese population. However, this analysis did not define the risks with respect to specific exposure values when considering levels of coffee consumption per day in the study population.

Methods: We conducted a two-stage random-effects dose-response meta-analysis of the association between coffee consumption and colorectal cancer among the Japanese. This was performed by modeling coffee consumption using restricted cubic splines to be able to examine a potential nonlinear relation.

Results: We identified a total of 26 studies from seven articles, which were distributed separately according to sex and colon/rectum cancers. Data from 14 cohort studies showed that the pooled relative risks for colorectal cancers were less than 1.0 in cases with coffee consumption of 1–3 cups/day and 1.0 in cases with consumption of 4 cups/day or more, although these results were not statistically significant. Data from 12 case-control studies showed that the pooled odds ratios for cancer risk were significantly less than 1.0 in cases with coffee consumption of 1–6 cups/day.

Conclusions: Findings from this meta-analysis indicate that moderate coffee consumption may not be associated or may be weakly inversely associated with the risk of colorectal cancer in the Japanese population.

Background: Excessive alcohol intake has been shown to be associated with cardiovascular disease via metabolic pathways. However, the relationship between alcohol intake and obesity has not been fully elucidated. We aimed to examine the association of alcohol consumption with fat deposition and anthropometric measures.

Methods: From 2006–2008, we conducted a cross-sectional study in a population-based sample of Japanese men aged 40 through 79 years. Areas of abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were calculated using computed tomography imaging. Based on a questionnaire, we classified participants into five groups according to weekly alcohol consumption, excluding former drinkers: non-drinkers (0 g/week), 0.1–160.9, 161–321.9, 322–482.9, and ≥483 g/week. Multivariable linear regression was used to estimate adjusted means of obesity indices for each group.

Results: We analyzed 998 men (mean age and body mass index [BMI], 63.8 years and 23.6 kg/m², respectively). Higher weekly alcohol consumption was strongly and significantly associated with higher abdominal VAT area, percentage of VAT, and VAT-to-SAT ratio (all P for trend <0.001), and also with waist circumferences and waist-to-hip ratio (P for trend = 0.042 and 0.007, respectively). These associations remained significant after further adjustment for BMI, whereas alcohol consumption had no significant association with abdominal SAT area.

Conclusions: Higher alcohol consumption was associated with higher VAT area, VAT%, and VAT-to-SAT ratio, independent of confounders, including BMI, in general Japanese men. These results suggest that alcohol consumption may have a potential adverse effect on visceral fat deposition.

Methods: We conducted a prospective cohort study using data from the Ibaraki Prefectural Health Study conducted from 1993 through 2013. The cohort included 97,078 adults (33,138 men and 63,940 women) living in Ibaraki Prefecture who were aged 40–79 years at an annual health checkup in 1993. We divided participants into four smoking status groups: non-smokers, ex-smokers, and current smokers who smoked <20 and ≥20 cigarettes per day. Hazard ratios (HRs) of traffic accident death were calculated using a Cox proportional hazards model.

Results: During 20 years of follow-up, the average person-years of follow-up were 16.8 and 18.2 in men and women, respectively. Among men, after adjusting for age and alcohol intake, HRs for traffic accident death among current smokers of <20 cigarettes/day and ≥20 cigarettes/day compared to non-smokers were 1.32 (95% confidence interval [CI], 0.79–2.20) and 1.54 (95% CI, 0.99–2.39), respectively. In contrast, among women, we found no association between smoking status and traffic accident deaths.

Conclusion: In this prospective cohort study, we found a positive association, though marginally significant, between smoking and traffic accident death among men in Japan. Among women, because of the smaller number of deaths among smokers, adequate estimation could not be obtained.

Background: Oxidative stress, the imbalance between pro- and antioxidants, has been implicated in the etiology and pathophysiology of the incidence and mortality of many diseases. We aim to investigate the relations of dietary intakes of vitamin C and E and main carotenoids with all-cause mortality in Japanese men and women.

Methods: The Japan Collaborative Cohort Study for Evaluation of Cancer Risk had 22,795 men and 35,539 women, aged 40–79 years at baseline (1988–1990), who completed a valid food frequency questionnaire and were followed up to the end of 2009.

Results: There were 6,179 deaths in men and 5,355 deaths in women during the median follow-up of 18.9 years for men and 19.4 years for women. Multivariate hazard ratios for the highest versus lowest quintile intakes in women were 0.83 (95% confidence interval [CI], 0.76–0.90; P for trend < 0.0001) for vitamin C, 0.85 (95% CI, 0.78–0.93; P for trend < 0.0001) for vitamin E, 0.88 (95% CI, 0.81–0.96; P for trend = 0.0006) for β-carotene, and 0.90 (95% CI, 0.82–0.98; P for trend = 0.0002) for β-cryptoxanthin. The joint effect of any two of these highly correlated micronutrients showed significant 12–17% reductions in risk in the high-intake group compared with the low-intake group in women. These significant associations were also observed in the highest quintile intakes of vitamin C, vitamin E, and β-carotene in female non-smokers but were not observed in female smokers, male smokers, and non-smokers.

Conclusions: Higher dietary intakes of antioxidant vitamins may reduce the risk of all-cause mortality in middle-aged Japanese women, especially female non-smokers.

Background: Maternal pre-pregnancy weight has been reported to be positively associated with offspring weight. The association between maternal weight and offspring weight might be explained by maternal lifestyle. We investigated the strength of the relationship between maternal body mass index (BMI) at the beginning of pregnancy and offspring BMI at several growth stages.

Methods: The source population was all eighth graders registered in all public schools in the city of Fukuroi, Japan, in 2012. Records of maternal anthropometry at the beginning of pregnancy were obtained from the Maternal and Child Health (MCH) Handbook. The height and body weight of each student were measured. A regression model was used to assess the association between maternal BMI z-score at the beginning of pregnancy and offspring BMI z-score at various ages.

Results: Of the source population, data from the MCH Handbook were obtained for 480 students. Among males, maternal BMI z-score was not associated with offspring BMI z-score at birth and at age 3 years but was associated with offspring BMI z-score at age 13 years (standardized regression coefficient (β) = 0.19; P < 0.01). Among females, maternal BMI z-score was associated with offspring BMI z-score at birth (β = 0.11; P < 0.05), at age 3 years (β = 0.22; P < 0.01) and at age 13 years (β = 0.51; P < 0.01).

Conclusions: Our results suggest that the positive association between maternal weight at the beginning of pregnancy and offspring weight around puberty is stronger than that between maternal weight and offspring weight at birth. Maternal lifestyle may influence offspring weight in adolescence.

Background: Acrylamide, a probable carcinogen to humans, forms during high temperature cooking. Dietary exposure to acrylamide among the Japanese population is unknown. We aimed to establish and validate a method to assess acrylamide exposure among the Japanese population using a food frequency questionnaire (FFQ) from the Japan Public Health Center-based prospective study.

Methods: Validation studies for the FFQ were conducted in 1994 (Cohort I, n = 215) and 1996 (Cohort II, n = 350). The 28-day dietary records (DRs) were collected over 1 year. The FFQ was distributed before and after DR collection. Data for acrylamide exposure were based on reported measurements in Japan, and calculations considered the cooking process for specific vegetables in a home setting. Spearman’s rank correlation and weighted kappa coefficients were calculated from energy-adjusted data.

Results: Mean acrylamide intake levels estimated from DRs for Cohorts I and II were 6.78 (standard deviation [SD], 3.89) µg/day and 7.25 (SD, 3.33) µg/day, and corresponding levels estimated from the FFQ were 7.03 (SD, 4.30) µg/day and 7.14 (SD, 3.38) µg/day, respectively. Deattenuated correlation coefficients for men and women were 0.54 and 0.48 in Cohort I and 0.40 and 0.37 in Cohort II, respectively. Weighted kappa coefficients were over 0.80 in all cases. The main contributing food groups from DRs were beverages, confectioneries, vegetables, potatoes and starches, and cereals.

Conclusions: High kappa values validate the use of FFQ in epidemiological studies. The marked contribution of cooked vegetables indicates the importance of considering household cooking methods in assessing acrylamide intake levels in the Japanese population.

Background: Dengue is a clinically important arthropod-borne viral disease with increasing global incidence. Here we aimed to estimate the prevalence of dengue infections in Khanh Hoa Province, central Viet Nam, and to identify risk factors for infection.

Methods: We performed a stratified cluster sampling survey including residents of 3–60 years of age in Nha Trang City, Ninh Hoa District and Dien Khanh District, Khanh Hoa Province, in October 2011. Immunoglobulin G (IgG) and immunoglobulin M (IgM) against dengue were analyzed using a rapid test kit. Participants completed a questionnaire exploring clinical dengue incidence, socio-economic status, and individual behavior. A household checklist was used to examine environment, mosquito larvae presence, and exposure to public health interventions.

Results: IgG positivity was 20.5% (urban, 16.3%; rural, 23.0%), IgM positivity was 6.7% (urban, 6.4%; rural, 6.9%), and incidence of clinically compatible dengue during the prior 3 months was 2.8 per 1,000 persons (urban, 1.7; rural, 3.4). For IgG positivity, the adjusted odds ratio (AOR) was 2.68 (95% confidence interval [CI], 1.24–5.81) for mosquito larvae presence in water pooled in old tires and was 3.09 (95% CI, 1.75–5.46) for proximity to a densely inhabited area. For IgM positivity, the AOR was 3.06 (95% CI, 1.50–6.23) for proximity to a densely inhabited area.

Conclusions: Our results indicated rural penetration of dengue infections. Control measures should target densely inhabited areas, and may include clean-up of discarded tires and water-collecting waste.

Background: Our objective in this study was to find determinants of high-school dropout in a deprived area of Japan using longitudinal data, including socio-demographic and junior high school-period information.

Methods: We followed 695 students who graduated the junior high school located in a deprived area of Japan between 2002 and 2010 for 3 years after graduation (614 students: follow-up rate, 88.3%). Multivariable log-binomial regression models were used to calculate the prevalence ratios (PRs) for high-school dropout, using multiple imputation (MI) to account for non-response at follow-up.

Results: The MI model estimated that 18.7% of students dropped out of high school in approximately 3 years. In the covariates-adjusted model, three factors were significantly associated with high-school dropout: ≥10 days of tardy arrival in junior high school (PR 6.44; 95% confidence interval [CI], 1.69–24.6 for “10–29 days of tardy arrival” and PR 8.01; 95% CI, 2.05–31.3 for “≥30 days of tardy arrival” compared with “0 day of tardy arrival”), daily smoking (PR 2.01; 95% CI, 1.41–2.86) and severe problems, such as abuse and neglect (PR 1.66; 95% CI, 1.16–2.39). Among students with ≥30 days of tardy arrival in addition to daily smoking or experience of severe problems, ≥50% high-school dropout rates were observed.

Conclusions: Three determinants of high-school dropout were found: smoking, tardy arrival, and experience of severe problems. These factors were correlated and should be treated as warning signs of complex behavioral and academic problems. Parents, educators, and policy makers should work together to implement effective strategies to prevent school dropout.

Background: There has been no nationwide analysis of travel time for hospital admission in Japan. Factors associated with travel time are also unknown. This study aimed to describe the distribution of travel time for hospital admission of cancer patients and identify underlying factors.

Methods: The individual data from the Patient Survey in 2011 were linked to those from the Survey of Medical Institutions in the same year, and GIS data were used to calculate driving travel time between the addresses of medical institutions and the population centers of municipalities where patients lived. Proportions of patients with travel time exceeding versus not exceeding 45 minutes were calculated. To analyze the data with consideration of both individual factors of patients and geographical characteristics of areas where patients lived, multilevel logistic model analysis was performed.

Results: The analysis included 50,845 cancer inpatients. The majority of the cancer patients (approximately 80%) were admitted to hospitals located less than a 45-minute drive from their residences. The travel time tended to be longer for younger patients. The proportion of patients with travel time ≥45 minutes was lower among those with stomach or colorectal cancer (approximately 15%) than those with cervical cancer or leukemia (approximately 30%). The lack of designated cancer care hospitals in the secondary healthcare service areas was significantly associated with travel time.

Conclusions: Selection of hospitals by cancer inpatients is affected by age, cancer sites, and availability of designated cancer care hospitals in the secondary healthcare service areas where patients live.

Background: Smoking and alcohol are established risk factors for several types of cancer, but the effects on biliary cancers, comprising biliary tract cancer (BTC) and intrahepatic bile duct cancer (IHBDC), have been inconclusive.

Methods: In this population-based prospective cohort study in Japan, we investigated the association of smoking and alcohol consumption with the risks of BTC and its subtypes and IHBDC incidence in men and women. Furthermore, the association of smoking stratified by drinking status was investigated. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the Cox proportional hazard model.

Results: A total of 48,367 men and 54,776 women aged 40–69 years were enrolled from 1990 through 1994 and followed up for 846,417 person-years in men and 1,021,330 person-years in women until 2012, during which 246 BTC and 80 IHBDC male cases and 227 BTC and 60 IHBDC female cases were identified. In men, smoking was significantly associated with an increased risk of IHBDC (HR 2.25; 95% CI, 1.19–4.25 for current smokers with ≥30 pack-years compared with non-smokers), and the risk was enhanced among regular drinkers compared with non/occasional-drinkers (HR 3.48; 95% CI, 1.41–8.61). A non-significant increase of IHBDC risk associated with alcohol was observed. Neither smoking nor alcohol consumption was associated with BTC risk. In women, the association of smoking and alcohol consumption with IHBDC and BTC was unclear because current smokers and regular drinkers were very few.

Conclusion: Our findings suggest that smoking increases IHBDC risk in men, especially among regular drinkers.

Background: We estimated the cumulative risk of type 2 diabetes from age 30 to 65 years in a large working population in Japan.

Methods: We used data from the Japan Epidemiology Collaboration on Occupational Health Study. Participants (46,065 men and 7,763 women) were aged 30–59 years, free of diabetes at baseline, and followed up for a maximum of 7 years. Incident type 2 diabetes was defined based on fasting and casual glucose, glycated hemoglobin, and current medical treatment for type 2 diabetes. We calculated the sex-specific cumulative risk of type 2 diabetes using the Practical Incidence Estimator macro, which was created to produce several estimates of disease incidence for prospective cohort studies based on a modified Kaplan-Meier method.

Results: During 274,349 person-years of follow-up, 3,587 individuals (3,339 men and 248 women) developed type 2 diabetes. The cumulative risk was 34.7% (95% confidence interval, 33.1–36.3%) for men and 18.6% (95% confidence interval, 15.5–21.7%) for women. In BMI-stratified analysis, obese (BMI ≥30 kg/m²) and overweight (BMI 25–29.9 kg/m²) men and women had a much higher cumulative risk of type 2 diabetes (obese: 77.3% for men and 64.8% for women; overweight: 49.1% and 35.7%, respectively) than those with BMI <25 kg/m² (26.2% and 13.4% for men and women, respectively).

Conclusions: The present data highlight the public health burden of type 2 diabetes in the working population. There is a need for effective programs for weight management and type 2 diabetes screening, especially for young obese employees, to prevent or delay the development of type 2 diabetes.

Background: Several studies have reported the adverse effects of caffeine intake during pregnancy on fetal health. However, the effects of caffeine intake from green and oolong teas has not been investigated, despite the considerable consumption of these teas in Japan and the potential inhibitory effects of catechins—chemicals present at relatively high levels in green and oolong teas—on folic acid absorption. The potential associations of serum folate levels with caffeinated beverage consumption and catechin levels remain largely unstudied. The present study aimed to determine these associations in pregnant Japanese women.

Methods: Pregnant women (n = 2,701) not receiving folate supplementation were enrolled at the Chiba Unit Center, a regional site of the Japan Environment and Children’s Study (JECS). Serum folate levels were measured using an Access folate assay kit, and nutrient and caffeine intakes were assessed using a self-administered food frequency questionnaire that was previously evaluated in Japanese populations.

Results: The low and normal serum folate groups reported caffeine intakes of 42.3 mg/1,000 kcal and 34.4 mg/1,000 kcal, respectively, and tannin intakes of 40.8 mg/1,000 kcal and 36.3 mg/1,000 kcal, respectively. Multiple regression analyses revealed negative associations of serum folate levels with caffeine and tannin intakes and a positive association between serum folate levels and dietary folate intake.

Conclusions: Considering the negative associations of caffeine and tannin levels with serum folate levels, pregnant women should consume caffeinated beverages, such as coffee and green/oolong teas, with caution.

Background: Physical activity questionnaires (PAQs) used in large-scale Japanese cohorts have rarely been simultaneously validated against the gold standard doubly labeled water (DLW) method. This study examined the validity of seven PAQs used in Japan for estimating energy expenditure against the DLW method.

Methods: Twenty healthy Japanese adults (9 men; mean age, 32.4 [standard deviation {SD}, 9.4] years, mainly researchers and students) participated in this study. Fifteen-day daily total energy expenditure (TEE) and basal metabolic rate (BMR) were measured using the DLW method and a metabolic chamber, respectively. Activity energy expenditure (AEE) was calculated as TEE − BMR − 0.1 × TEE. Seven PAQs were self-administered to estimate TEE and AEE.

Results: The mean measured values of TEE and AEE were 2,294 (SD, 318) kcal/day and 721 (SD, 161) kcal/day, respectively. All of the PAQs indicated moderate-to-strong correlations with the DLW method in TEE (rho = 0.57–0.84). Two PAQs (Japan Public Health Center Study [JPHC]-PAQ Short and JPHC-PAQ Long) showed significant equivalence in TEE and moderate intra-class correlation coefficients (ICC). None of the PAQs showed significantly equivalent AEE estimates, with differences ranging from −547 to 77 kcal/day. Correlations and ICCs in AEE were mostly weak or fair (rho = 0.02–0.54, and ICC = 0.00–0.44). Only JPHC-PAQ Short provided significant and fair agreement with the DLW method.

Conclusions: TEE estimated by the PAQs showed moderate or strong correlations with the results of DLW. Two PAQs showed equivalent TEE and moderate agreement. None of the PAQs showed equivalent AEE estimation to the gold standard, with weak-to-fair correlations and agreements. Further studies with larger sample sizes are needed to confirm these findings.

Background: Participation in community activities (eg, sports and hobby groups or volunteer organizations) is believed to be associated with better health status in the older population. We sought to (1) determine whether a greater diversity of group membership is associated with better self-rated health and (2) identify the key dimension of the membership diversity (eg, gender, residential area, or age).

Methods: We performed a cross-sectional study of 129,740 participants aged 65 years and older who were enrolled in the Japan Gerontological Evaluation Study in 2013. We assessed the diversity of group membership using (1) a continuous variable (range 0–4) accounting for the total degree of each diversity dimension or (2) dummy variables for each dimension. We estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) for better self-rated health according to the diversity of group membership, using Poisson regression and robust variance with multiple imputation, adjusted for other covariates.

Results: The participants involved in social groups with greater diversity had better self-rated health: the PR per one point unit increase in diversity was 1.03 (95% CI, 1.02–1.04). Participation in gender-diverse groups was associated with the best profile of health (PR 1.07; 95% CI, 1.04–1.09).

Conclusions: Among the older population in Japan, higher group diversity is associated with better self-rated health. Gender is the key dimension of diversity that is associated with better self-rated health.

Background: There is scarce epidemiological evidence regarding the relationships of the consumption of different types of vegetables or fruits with change in skeletal muscle strength. We prospectively examined the relationships among Japanese adults, using handgrip strength to assess skeletal muscle strength.

Methods: A 3-year study was carried out with 259 Japanese adults who were 22–68 years of age. The frequency of consumption of different types of vegetables or fruits were obtained using a validated self-administered dietary history questionnaire. Handgrip strength was measured with a handheld digital Smedley dynamometer.

Results: After adjustment for confounding factors, the mean change in handgrip strength in participants stratified according to the level of tomato and tomato product consumption at baseline were −3.2 (95% confidence interval [CI], −4.0 to −2.3) for <1 time/week, −2.7 (95% CI, −3.6 to −1.8) for 1 time/week, −1.6 (95% CI, −2.5 to −0.8) for 2–3 times/week, and −1.7 (95% CI, −2.8 to −0.7) for ≥4 times/week, (P for trend = 0.022). However, the significant relationships of consumption of other types of vegetables and different types of fruits with change in handgrip strength were not observed.

Conclusion: Higher consumption of tomato and tomato product at baseline was significantly associated with reduced decline in handgrip strength among Japanese adults over a 3-year follow-up period. This study suggests that consumption of tomato and tomato product could be protective against the decline in skeletal muscle strength associated with aging.

Background: Foodborne norovirus outbreak data in Japan from 2005–2006, involving virological surveillance of all symptomatic and asymptomatic individuals, were reanalyzed to estimate the asymptomatic ratio of norovirus infection along with the risk of infection and the probability of virus shedding.

Methods: Employing a statistical model that is considered to capture the data-generating process of the outbreak and virus surveillance, maximum likelihood estimation of the asymptomatic ratio was implemented.

Results: Assuming that all norovirus outbreaks (n = 55) were the result of random sampling from an identical distribution and ignoring genogroup and genotype specificities, the asymptomatic ratio was estimated at 32.1% (95% confidence interval [CI], 27.7–36.7). Although not significant, separate estimation of the asymptomatic ratio of the GII.4 genotype appeared to be greater than other genotypes and was estimated at 40.7% (95% CI, 32.8–49.0).

Conclusion: The present study offered the first explicit empirical estimates of the asymptomatic ratio of norovirus infection in natural infection settings. The estimate of about 30% was consistent with those derived from volunteer challenge studies. Practical difficulty in controlling GII.4 outbreaks was supported by the data, considering that a large estimate of the asymptomatic ratio was obtained for the GII.4 genotype.

Background: Prolonged screen time (ST), which includes TV viewing and gaming on smartphones and computers, is linked to poor health. Our aim was to explore the associations between school children with prolonged ST and parental internet use (IU) and lifestyles in Japan.

Methods: Children aged 6 to 13 years from the Super Shokuiku School Project, were surveyed using questionnaires in 2016. The survey assessed the grade, sex, and lifestyle of 1,659 children and parental internet use (IU) and lifestyle using Breslow’s seven health behaviors. IU consisted of internet surfing and gaming on personal computers (PC), smartphones, or consoles. Three or more hours of ST was defined as prolonged ST, and its correlates were analyzed using logistic regression.

Results: Of all, 643 (38.8%) children spent ≥2 hours/day of ST on a week day, whilst 153 (9.2%) children spent ≥3 hours/day. Prolonged ST was significantly associated with children in higher grade (odds ratio [OR] 1.74; 95% confidence interval [CI], 1.20–2.51), boys (OR 2.16; 95% CI, 1.49–3.14), skipping breakfast (OR 1.88; 95% CI, 1.05–3.35), late bedtime (OR 1.80; 95% CI, 1.15–2.82), physical inactivity (OR 1.79; 95% CI, 1.12–2.87), father’s IU ≥2 hours/day (OR 2.35; 95% CI, 1.52–3.63), mother’s prolonged IU ≥2 hours/day (OR 2.55; 95% CI, 1.43–4.52), mothers with unhealthy behaviors (OR 1.81; 95% CI, 1.05–3.13), no rule setting governing screen time (OR 2.41; 95% CI, 1.63–3.58), and mothers with full-time employment (OR 1.95; 95% CI, 1.06–3.64).

Conclusions: Prolonged ST among Japanese children was strongly associated with parental IU, no set rules for ST, and mother’s unhealthy lifestyles. To reduce children’s ST, parental engagement is warranted in the intervention strategy.

Background: Deterioration of hand motor function is a possible risk factor of cognitive impairment in older adults. Despite a growing body of research, a lack of clarity exists regarding the relationships. This review offers a synthesis of existing observational studies evaluating the associations of handgrip strength and hand dexterity with cognitive performance in community-dwelling older adults.

Methods: PubMed, PsycINFO, and ScienceDirect were systematically searched (search dates: 1990–2016), and relevant articles were cross-checked for related and relevant publications.

Results: Twenty-two observational studies assessed the association of handgrip strength or hand dexterity with cognitive performance; none evaluated handgrip strength and hand dexterity together. Handgrip strength was associated with global cognition, mostly assessed using the Mini-Mental State Examination, cross-sectionally and longitudinally. Also, one cross-sectional and three longitudinal studies found an association with cognitive domains, such as language, memory, visuospatial ability, working memory, and processing speed. Hand dexterity was only assessed cross-sectionally in four studies. These studies found an association with cognitive domains, such as executive function.

Conclusions: Although handgrip strength was associated with cognitive performance, it is unclear which variable at baseline affects the other in the long-term. Cross-sectional studies indicate an association between hand dexterity and cognitive performance, yet longitudinal studies are needed to elucidate this association. The interaction effects of both decreased grip strength and hand dexterity on cognitive performance is still unclear; therefore, future studies will need to consider the interaction of the three variables cross-sectionally and longitudinally.

Background: Recent improvements in 5-year survival of breast cancer have been reported in Japan and other countries. Though the number of long-term breast cancer survivors has been increasing, recent improvements in 10-year survival have not been reported. Moreover, the degree of improvement according to age and disease stage remains unclear.

Methods: We calculated long-term survival using data on breast cancer diagnosed from 1993 through 2006 from six prefectural population-based cancer registries in Japan. The recent increase in 10-year relative survival was assessed by comparing the results of period analysis in 2002–2006 with the results of cohort analysis in 1993–1997. We also conducted stratified analyses by age group (15–34, 35–49, 50–69, and 70–99 years) and disease stage (localized, regional, and distant).

Results: A total of 63,348 patients were analysed. Ten-year relative survival improved by 2.4% (76.9% vs 79.3%) from 1993 through 2006. By age and stage, 10-year relative survival clearly improved in the age 35–49 years (+2.9%; 78.1% vs 81.0%), 50–69 years (+2.8%; 75.2% vs 78.0%) and regional disease (+3.4%; 64.9% vs 68.3%). In contrast, the degree of improvement was small in the age 15–34 years (+0.1%; 68.2% vs 68.3%), 70–99 years (+1.0%; 87.6% vs 88.6%), localized disease (+1.1%; 92.6% vs 93.7%) and distant metastasis (+0.9%; 13.8% vs 14.7%).

Conclusions: These population-based cancer registry data show that 10-year relative survival improved 2.4% over this period in Japan. By age and stage, improvement in the age 15–34 years and distant metastasis was very small, which suggests the need for new therapeutic strategies in these patients.