Many developments in the design and analysis of environmental epidemiology have been made in air pollution studies. In the analysis of the short-term effects of particulate matter on daily mortality, Poisson regression models with flexible smoothing methods have been developed for the analysis of time-series data. Another option for such studies is the use of case–crossover designs, and there have been extensive discussions on the selection of control periods. In the Study on Respiratory Disease and Automobile Exhaust project conducted by the Japanese Ministry of the Environment, we adopted a new 2-stage case–control design that is efficient when both exposure and disease are rare. Based on our experience in conducting air pollution epidemiologic studies, we review 2-stage case–control designs, case–crossover designs, generalized linear models, generalized additive models, and generalized estimating equations, all of which are useful approaches in environmental epidemiology.
Although a number of epidemiological studies have reported that psychological factors are associated with increased risk of cardiovascular morbidity and mortality, the relevant epidemiological data are mostly limited to Western populations. The present study sought to examine associations of depressive symptoms, anger expression, and tension with the incidence of cardiovascular disease in the Circulatory Risk in Communities Study (CIRCS). Depressive symptoms were measured in 901 men and women by using the Zung Self-Rating Depression Scale (SDS); anger expression and tension were measured in 6292 men and women by using the Anger Expression Scale and Framingham Tension Scale. As compared with the participants with SDS scores in the lowest tertile, those with scores in the highest tertile had twice the age- and sex-adjusted hazard ratio of total stroke. However, this excess risk was present only for ischemic stroke. Participants in the highest tertile also had a 7-fold adjusted hazard ratio of coronary heart disease, as compared with those in the lowest tertile. These associations were virtually unchanged after further adjustment for covariates. Men with “anger-in” scores in the highest tertile had a 1.5-fold age-adjusted relative risk of hypertension as compared with those in the lowest tertile; anger-in score was not associated with hypertension in women. In men and women, there were no associations between hypertension and either “anger-out” or tension scores. These findings generally support the hypothesis that—as is the case in Western populations—anger suppression and depression increase the risk of cardiovascular disease among Japanese.
Background: This retrospective cohort study examined the sex- and age-specific impact of hypertension on medical expenditures. Methods: In 2006, we analyzed the medical expenditure records of 42 426 Japanese National Health Insurance beneficiaries (16 169 men, 26 257 women) who lived in Ibaraki, Japan, were aged 40 to 69 years, and underwent health checkups in 2002. Blood pressure was classified into 4 categories according to the criteria outlined in the seventh report of the Joint National Committee. Results: The difference in median total expenditure between the hypertension categories and the normotension category was 119 585 yen (140 360 yen vs 20 775 yen) for men aged 40 to 54 years, 126 160 yen (204 070 yen vs 77 910 yen) for men aged 55 to 69 years, 125 495 yen (158 025 yen vs 32 530 yen) for women aged 40 to 54 years, and 122 370 yen (208 700 yen vs 86 330 yen) for women aged 55 to 69 years. The median total and outpatient medical expenditures markedly differed between patients with stage 1 hypertension and stage 2 hypertension (which included people on antihypertensive medication) in both sexes and all age subgroups. The median total and outpatient medical expenditures were higher among women than among men in all blood pressure categories. Conclusions: The impact of hypertension on medical expenditures was similar in all age groups. Therefore, from the perspective of medical economics, prevention of the onset of hypertension seems equally important for all age subgroups.
Objective: The use of dietary supplements has been increasing rapidly in Korea over the last decade. The aim of this study was to investigate associations between the pattern of dietary supplement use and the sociodemographic/lifestyle characteristics of Korean consumers. Methods: Participants were asked to complete a self-administered questionnaire on their sociodemographic and lifestyle characteristics, perceived health status, and regular dietary supplement use. Results: A total of 697 men and 832 women completed the questionnaire. Of the respondents, 44.3% of the men and 53.2% of the women used some kind of dietary supplement regularly. Dietary supplement users were more likely to be women (P < 0.001), to be older than 50 years (P < 0.001), to have a higher household income (P = 0.003), to engage in moderate or vigorous physical activity (P < 0.032), to perceive themselves as healthy (P = 0.026), and to have received a diagnosis of a chronic disease (P < 0.001). In addition, the type of dietary supplements used varied with respect to sociodemographic and lifestyle factors. Among dietary supplement users, men preferred ginseng, and older respondents were more likely to use carbohydrate supplements and less likely to use lipid supplements. Those who had a lower BMI, were ex-smokers, or were nondrinkers preferred either vitamins or minerals. Those who were highly physical active or were nondrinkers tended to prefer either vitamin/mineral complexes or carbohydrate supplements. Conclusions: The use of dietary supplements was related to sociodemographic and lifestyle factors in a Korean population.
Background: Alcohol consumption is a known risk factor for cancers of the mouth, esophagus, liver, colon, and breast. In this study, we examined the association between alcohol consumption and digestive cancer mortality in Korean men and women. Methods: A cohort of 6291 residents of Kangwha County who were aged 55 years or older in March 1985 were followed to 31 December 2005—a period of 20.8 years. We calculated the relative risks of cancer mortality with respect to the amount of alcohol consumed. Cox proportional hazard model was used to adjust for age at entry, smoking, ginseng intake, education status, and pesticide use. Results: In men, the risks of mortality from esophageal cancer (relative risk [RR], 5.62; 95% confidence interval [CI], 1.45–21.77) and colon cancer (RR, 4.59; 95% CI, 1.10–19.2) were higher among heavy drinkers, as compared with abstainers. The risks of mortality from colon cancer and bile duct cancer rose with increasing alcohol consumption; these trends were positive and statistically significant (P = 0.04 and P = 0.02, respectively). When participants were stratified by type of alcoholic beverage, soju drinkers had higher risks of mortality from esophageal cancer and colon cancer than makkoli drinkers. In women, the risk of digestive cancer mortality was higher among alcohol drinkers than abstainers, but this difference was not statistically significant. Conclusions: Alcohol consumption increases mortality from esophageal cancer and colon cancer in men.
Background: Current trends in body size, blood pressure, and serum lipids in children are predictors of future disease prevalence. However, there have been no studies of blood pressure and high-density lipoprotein cholesterol (HDL-C) levels in Japanese children. Methods: We investigated trends in body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), non-HDL-C, and HDL-C using data from annual screenings in 1993 through 2008. The subjects were 14 872 (98.8% of the target population) fifth-graders enrolled in all public schools in the Original Iwata area in Iwata City, Japan. The same examination protocol was used throughout to ensure the uniformity of quality control and the precision of assessment. Trends in the variables in relation to the calendar year were analyzed by using regression models. Results: In boys, the 95th percentile of BMI increased by 0.09 kg/m2/year. In both sexes, the 5th percentile of BMI decreased by 0.02 to 0.03 kg/m2/year. There was a significant negative correlation between SBP and calendar year, and the 95th percentile of SBP decreased by 0.52 mm Hg/year in boys and by 0.40 mm Hg/year in girls. There was also a significant reduction DBP. However, there were no trends in TC, non-HDL-C, or HDL-C. Conclusions: The increase in obese and underweight children in Original Iwata was consistent with the findings of a nationwide survey. Although high blood pressure and related risk factors were formerly a serious problem in Japan, blood pressure levels have decreased in schoolchildren from Iwata over the past 15 years.
Background: Metabolic syndrome (MetS) and hyperuricemia are important risk factors for cardiovascular disease. However, findings regarding the relationship between serum uric acid (UA) level and components of MetS have been inconsistent. This study was performed to explore the potential value of UA level as a marker of MetS among male and female Chinese of different ages. Methods: A total of 5896 subjects (2960 females and 2936 males) were recruited from the Department of Health Management at the Chang Gung Medical Center. Hyperuricemia was defined as a serum UA value >7.0 mg/dL for males or >6.0 mg/dL for females. MetS was defined according to the criteria of the Adult Treatment Panel III, as modified for Chinese subjects. Serum UA was used to differentiate MetS and to calculate epidemiological indices by means of discriminate analysis and logistic regression. Results: The sensitivity and specificity of serum UA concentration as a marker of MetS ranged from 55.2% to 61.4% and 61.9% to 68.4%, respectively. Subjects with high UA had a higher risk of MetS, with odds ratios ranging from 1.23 to 1.82 (P < 0.01). A positive correlation between serum UA and MetS was observed in both sexes. Serum UA and the occurrence of MetS rose with increasing age in females; in males, however, UA values did not vary with age. Conclusions: Serum UA is more closely associated with MetS in females than in males. High UA among middle-aged women may predict the development of MetS.
Background: Many studies have reported an association between physical activity and cardiovascular disease (CVD); however, the effect of physical activity remains controversial. Few such studies have been conducted in Japan. Therefore, we examined the relationship between physical activity and death from CVD using prospective data from a Japanese population. Methods: From a prospective cohort study that comprised 12 490 participants, data from 9810 were analyzed. From April 1992 through July 1995, a baseline survey was conducted in 12 communities in Japan. The participants were followed up until December 2005. Physical activity was assessed using the physical activity index (PAI). PAI scores were grouped in quartiles: Q1 was the lowest PAI quartile and Q4 was the highest. Hazard ratios (HRs) for death from CVD, stroke, and myocardial infarction (MI) were calculated for all PAI quartiles. Results: The mean follow-up period was 11.9 years, during which time 194 participants died of CVD. With Q1 as the reference, the HRs for death from CVD in Q2, Q3, and Q4, were 0.62 (95% confidence interval, 0.40–0.98), 0.53 (0.31–0.88), and 0.40 (0.22–0.73), respectively, in men, and 0.71 (0.38–1.32), 0.52 (0.26–1.04), and 0.48 (0.22–1.05), respectively, in women. The HRs for death from CVD subtypes were similar but not statistically significant. Conclusions: Among a Japanese population, physical activity was associated with a decreased risk of death from CVD. However, more evidence is needed to elucidate the relationships between physical activity and CVD subtypes.
Background: The goal of this study was to determine the prevalence and risk factors for horizontal transmission of hepatitis B infection due to intravenous drug abuse (IVDA), tattooing, blood transfusion, and combinations of these risk factors. Methods: All people detained in 19 prisons were invited to participate. Subjects underwent a physical examination and completed a questionnaire. Blood samples were collected and screened for hepatitis B surface antigen and Venereal Disease Research Laboratory (VDRL) reactivity. Results: A total of 16 204 prisoners were invited to participate. The response rate was 92.6% and the mean age was 29.73 years. The overall prevalence of HBsAg positivity was 21.7%. Among 3333 subjects with a history of blood transfusion, the carrier rate was 23.19%. Among the 3071 subjects with a history of IVDA and the 6908 subjects with tattoos, the carrier rate was 26.4% and 29.3%, respectively. IVDA appeared to be the strongest risk factor among the 3, with an adjusted odds ratio (AOR) of 1.54 (95% confidence interval, 1.27–1.86), followed by tattooing (1.40, 1.23–1.55), and blood transfusion (1.27, 1.05–1.61). When blood transfusion was combined with either of the other 2 risk factors, the risk increased multiplicatively, and the combination of the 3 factors increased the AOR to 2.76 (2.20–3.47). The prevalence of a positive VDRL test result was 1.01%. Conclusions: The prevalence of HBV antigenemia in prisoners was high and was associated with BT, IVDA, and tattooing. A national vaccination program against HBV should be considered for prisoners and other people with these risk factors.
Background: We calculated new prevalences of risk factors for cardiovascular disease (CVD) and examined their associations with dietary habits and physical activity in a suburban area of Beijing—one of the most urbanized cities in China. Methods: In 2007, a cross-sectional survey of a representative sample of 19 003 suburban residents aged 18 to 76 years was conducted. Dietary and anthropometric data were collected by questionnaire, and blood pressure, fasting blood glucose, and serum lipids were measured. Results: The age-standardized prevalences of the CVD risk factors overweight/obesity, diabetes, hypertension, dyslipidemia, and metabolic syndrome (MS) were 31.9%, 6.1%, 33.6%, 30.3%, and 11.6%, respectively. The adjusted odd ratios (95% confidence interval [CI]) of overweight/obesity, diabetes, hypertension, dyslipidemia, and MS for participants who were physically active, as compared with those who were not physically active, were 0.67 (0.47 to 0.85), 0.87 (0.80 to 0.95), 0.92 (0.87 to 0.98), 0.89 (0.82 to 0.96), and 0.74 (0.62 to 0.89), respectively. The adjusted odds ratios (95% CI) of hypertension and MS for participants with a high intake of salt, as compared with those without a high intake of salt, were 1.72 (1.29 to 2.03) and 1.48 (1.16 to 1.77), respectively. In addition, participants who consumed a high-fat diet were more likely to be overweight/obese and dyslipidemic, whereas vegetarians had less risk of overweight/obesity, diabetes, hypertension, dyslipidemia, and MS. Conclusions: In this population of adults living in suburban Beijing, there were relatively high prevalences of the CVD risk factors overweight/obesity, diabetes, hypertension, dyslipidemia, and MS. Healthy dietary habits and physical activity may reduce the risks of these conditions.
Background: There have been only a limited number of trend analyses of incidence and mortality using population-based cancer registry data in Japan, and the national statistics regarding incidence are estimated data. In the present study, data from the Fukui Prefecture cancer registry, which is the most accurate in Japan, were used to observe trends in incidence and mortality rates. Methods: Cancer incidence and mortality rates from 1984 through 2004 were obtained from the Fukui Prefecture cancer registry. Joinpoint analysis developed for the US National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program was used to compute and graphically present annual percentage changes in age-adjusted incidence and mortality in Fukui Prefecture. Results: On joinpoint analysis, there were slight increases in incidence at all cancer sites combined for both sexes from 1986, but the trend was not significant in Fukui. Mortality in women appeared to significantly decrease, while mortality in men, which had been increasing until 1999, began to significantly decrease thereafter. In an analysis by anatomical site, both the incidence and mortality of stomach cancer significantly decreased in both sexes. However, the incidence and mortality of breast and prostate cancers significantly increased. The mortality of liver and lung cancers also increased in both sexes. Conclusions: Cancer mortality has been declining in recent years, and the reduction in mortality from stomach cancer has significantly affected the trends in Fukui. Urgent cancer control planning by the Fukui local government is necessary, especially for cancers of the liver, lung, prostate, and breast.
Background: Large-scale cohort studies conducted in Japan do not always include psychosocial factors as exposures. In addition, such studies sometimes fail to satisfactorily evaluate disability status as an outcome. Methods: This prospective cohort study comprised 49 603 (22 438 men and 27 165 women) community-dwelling adults aged 40 years or older who were included in the Residential Registry for Ohsaki City, Miyagi Prefecture, in northeastern Japan. The baseline survey, which included psychosocial factors, was conducted in December 2006. Follow-up of death, immigration, cause of death, cancer incidence, and long-term care insurance certification was started on 1 January 2007. Results: The response rate was 64.2%. In general, lifestyle-related conditions in the study population were similar to those of the general Japanese population; however, the proportion of male current smokers was higher in the cohort. The association between age and the proportion of those reporting psychological distress showed a clear U-shaped curve, with a nadir at age 60 to 69 years in both men and women, although more women were affected by such distress than men. The proportion of those who reported a lack of social support was highest among those aged 40 to 49 years. Most men and women surveyed did not participate in community activities. Among participants aged 65 years or older, 10.9% of participants were certified beneficiaries of the long-term care insurance system at baseline. Conclusions: The Ohsaki Cohort 2006 Study is a novel population-based prospective cohort study that focuses on psychosocial factors and long-term care insurance certification.