Background: Changes in nutritional status during the coronavirus disease 2019 (COVID-19) pandemic may be attributed to the obesity-causing environment that had existed before. This paper aimed to investigate trends in thinness, overweight, and obesity among Chinese children aged 2 to 18 years from 2010 to 2020 and assess the potential influence of pandemic.

Methods: The Chinese Family Panel Studies that were conducted every 2 years between 2010 and 2020 included 48,642 children between the ages of 2 and 18 years. Height and mass were reported, and the body mass index (BMI) was calculated. The prevalence of thinness, overweight, and obesity was estimated using sex- and age-specific BMI cut-offs adopted by the International Obesity Task Force and population-weighted procedures. Linear regressions were used to estimate trends.

Results: The prevalence of thinness decreased from 25.5% to 22.2% but increased among children aged 2 to 6 years. The prevalence of overweight and obesity decreased from 24.6% and 14.2% to 22.5% and 10.0%, respectively. However, these decreases in the prevalence of overweight and obesity were attributed mostly to children aged 2 to 6 years, and the prevalence increased slightly among children aged 13 to 18 years. The prevalence of obesity in 2020 among only boys aged 13 to 15 years was greater than the estimated projections using data from 2010 to 2018.

Conclusion: From 2010 to 2020, the prevalence of all forms of malnutrition among Chinese children decreased, with age disparities. During the pandemic, overweight became more common among pubertal boys. Future interventions as well as policies ought to give high-risk groups priority.

Introduction: Evidence is scarce on cumulative SARS-CoV-2 infections among healthcare workers during the pandemic. This study aimed to describe cumulative infections, including undiagnosed cases, and identify factors associated with infection in healthcare workers in Japan.

Methods: Using serosurveys conducted across six national centers in Japan, we tracked COVID-19 cumulative infections. Seropositivity was defined as a positive result for SARS-CoV-2 nucleocapsid protein using the Roche assay, and cumulative infection was defined as the proportion of participants who tested positive for anti-nucleocapsid antibodies and/or self-reported a history of laboratory-confirmed or clinically diagnosed COVID-19 since the start of the pandemic. A robust Poisson regression model was used to investigate factors associated with infection risk as of September 2023.

Results: Cumulative infection, which was less than 5% until the end of 2021, increased after the emergence of the Omicron variant. Specifically, cumulative infection reached 14.6% in July 2022 (BA.1/2), 37.4% in December 2022 (BA.5), 53.3% in September 2023 (XBB subvariants), and 71.5% in December 2023 (JN.1 subvariant). The proportion of undiagnosed cases detected by antibody testing alone, without a prior diagnosis, decreased from 60.9% in December 2020 to 24.7% in December 2023. Individuals aged 50 to 59 years (PR: 0.73; 95% confidence interval: 0.67–0.79) and 60 years or older (PR: 0.67; confidence interval: 0.59–0.77) had lower cumulative infections than those aged under 30 years old. Physicians and nurses had significantly higher cumulative infections than administrative staff, with fully adjusted prevalence ratios of 1.09 (95% confidence interval: 1.01–1.18) and 1.18 (95% confidence interval: 1.08–1.30), respectively.

Conclusion: Among healthcare workers in Japan, cumulative SARS-CoV-2 infection markedly increased after the emergence of the Omicron variant, whereas the proportion of undiagnosed cases has decreased throughout the pandemic. Younger people (<50 years), as well as physicians and nurses, have faced a higher risk of infection.

Background: In observational studies estimating the association between treatment and time-to-event outcomes, time-related biases can substantially impact results. Immortal time bias is one of such biases, and two types are known: misclassified immortal time bias and excluded immortal time bias. These biases often arise from incorrect time-zero definition, especially with non-user controls. This study aims to illustrate immortal time bias in non-user controls using formulas, simulations, and real-world data.

Methods: For our simulations, we considered two scenarios: one with no confounding and no treatment effect, and the other with time-dependent confounding. We compare three different settings of time-zero for treatment and control groups. Method 1: Both groups were followed from cohort entry date (CED). Method 2: The treatment group was followed from treatment initiation date (TID), while the non-user group was followed from CED. Method 3: The treatment group was followed from TID, and non-users were matched to treatment patients, followed from the corresponding TID of their matched patient.

Results: Our simulation showed that both Method 1 and Method 2 can exhibit large biases in the estimated treatment effect due to immortal time bias. The magnitude of the bias is greater for Method 1 than for Method 2. On the other hand, Method 3 showed almost no bias. Even in the presence of time-dependent confounding, Method 3 did not introduce bias.

Conclusions: To reduce time-related biases, it is crucial for researchers to carefully define an appropriate time-zero, especially when using a non-user control group.

Background

A World Health Organization guideline recommends that adults engage in moderate-to-vigorous physical activity (MVPA). We aimed to clarify associations of total MVPA in any domain with overall and site-specific cancer incidence using Japanese population-based cohort data.

Method

This study evaluated 84,054 participants (39,053 males and 45,001 females aged 50–79 years) of the 10-year survey of the Japan Public Health Center-based Prospective Study over a median follow-up of 13.0 years. Total MVPA was calculated based on a self-reported physical questionnaire, and 7.5 metabolic equivalent-hours/week (MET-h/wk) was defined as the minimum amount recommended by the guideline. Associations of categorized total MVPA with overall and site-specific cancer incidences were examined using multivariable-adjusted Cox proportional hazard models by sex.

Results

Among males, the risk reduction was non-significant even in the highest MVPA category compared with no total MVPA. Among females, in contrast, risk of total cancer was reduced even when they engaged in lower total MVPA than the recommended amount (0.1–7.4 MET-h/wk) compared with no total MVPA (hazard ratio 0.79 [95% confidence interval: 0.65–0.97]), and no further risk reduction was observed with increasing MVPA. Regarding site-specific cancers, engaging in higher total MVPA was inversely associated with risks of colon cancer (males) and bladder and endometrial cancers (females).

Conclusion

Total MVPA was associated with reduced risk of overall cancer incidence in females, but not in males.

Background: Cardiovascular disease (CVD) remains a leading cause of death in Japan. Although several CVD risk scores tailored for Japanese individuals have been developed, no tools are available to estimate these scores at the population level. We developed the “Jcvrisk” R package, which integrates four major Japanese CVD risk models recommended by the clinical guideline. As a showcase, we applied the Jcvrisk package to longitudinal population-based study to evaluate trends in estimated different risk scores.

Methods: We used longitudinal data from the Yakumo Study, an annual health checkup for residents in Yakumo, Hokkaido. This package includes four risk models with 14 risk scores from representative cardiovascular cohort studies, including three EPOCH scores, one Hisayama score, two Suita scores, and eight JALS scores. For temporal comparisons of CVD risk scores, we summarized scores from 2000 to 2020 every five years.

Results: The mean age of participants throughout all study years was around 60 years old. Most risk factors did not change remarkably over the 20 years, with only a decrease in smoking prevalence and an increase in high density lipoprotein cholesterol (HDL-C). However, all CVD risk scores consistently indicated an upward trend in 10-year CVD risk.

Conclusions: Jcvrisk package includes functions to calculate CVD risk scores for Japanese adults. The package serves as a valuable tool for researchers and policymakers aiming to assess and monitor cardiovascular risk at both individual and population levels in Japan.

Background: Policy decisions should be guided by measures that capture the impact of exposures on outcomes and that explicitly account for present-day exposure distribution. Both the preventable and attributable fractions have been used for this purpose; however, exposure effects can vary across subpopulations, and when this occurs, appropriate interpretation of these measures should be facilitated by a discussion of the contributions of different subpopulations.

Methods: We analyze preventable and attributable fractions in the presence of effect modification. In particular, we use potential outcomes to formally define these quantities and to clarify the weighting of different strata in the total population measures.

Results: Our derivations show that stratum-specific preventable and attributable fractions are weighted in proportion to the relative frequencies of effect modifiers among individuals with the outcome of interest. We also demonstrate that these weights are valid for the related quantities, preventable and attributable proportions. Finally, we present an example that illustrates how effect modification affects interpretation of these measures.

Conclusions: In sum, when effect modification is present, investigators should consider reporting these measures by the relevant population strata, and information that would allow quantification of their implicit weights in the total population estimate. Our study provides a formal justification for this approach.

Background: Despite Japan’s universal health insurance system, health disparities have increased since the 1990s. However, the impact of area deprivation on various aspects of child health remains understudied.

Methods: This population-based cohort study followed 38,554 children born in Japan (May 10–24, 2010) from birth to age 5.5 years. Using an outcome-wide approach, Bayesian three-level logistic regression models (individuals in municipalities within eight major regions) assessed associations between municipality-level Area Deprivation Index (ADI) at birth and multiple preschool health outcomes (hospitalizations for all causes; respiratory infections; gastrointestinal diseases; Kawasaki disease; medical visits for asthma, allergic rhinitis, atopic dermatitis, food allergy, injury, intussusception; prevalence of overweight/obesity), adjusting for individual-level factors.

Results: Higher ADI was associated with increased risk of all-cause hospitalization (adjusted odds ratio [aOR] per 1-standard-deviation increase in ADI, 1.04; 95% credible interval [CrI], 1.01–1.07), respiratory infections (aOR, 1.08; 95% CrI, 1.04–1.13), gastrointestinal diseases (aOR, 1.11; 95% CrI, 1.03–1.20), asthma (aOR, 1.10; 95% CrI, 1.01–1.19). Overweight/obesity at age 5.5 years also increased with higher ADI (aOR, 1.11; 95% CrI, 1.06–1.16). Higher ADI was inversely associated with Kawasaki disease (aOR, 0.86; 95% CrI, 0.77–0.96), though not robust in sensitivity analysis. Geographic clustering was observed for all outcomes, particularly at municipality level.

Conclusion: We found persistent municipal-level health inequalities across various childhood health outcomes in Japan, despite its universal health insurance system. These findings suggest that policymakers should address health inequalities through comprehensive strategies targeting broader social determinants beyond health care access.

Background: This study aimed to describe the clinical outcomes and medical costs of hospitalized children requiring daily medical care (CRDMC), a patient group for which government-led support has developed rapidly in Japan.

Methods: A retrospective longitudinal study was conducted using a nationwide administrative database. All hospitalizations of children aged under 18 years discharged from April 2014 to March 2021 were included. Clinical outcomes and medical costs were compared between CRDMC and non-CRDMC hospitalizations. The estimated increase in the proportion of CRDMC medical costs among all pediatric hospitalizations during the study period was also calculated.

Results: Among the 1,531,456 hospitalizations included, 91,413 were identified as CRDMC. CRDMC accounted for 3.7% of the annual unique inpatients. The 30-day readmission rate among CRDMC was 27.5%, and the rate among those receiving multiple types of medical care was higher at 33.7%. The inpatient medical cost of CRDMC accounted for 20.3% of pediatric inpatient medical costs, with an estimated rise of 1.2881 (95% confidence interval, 1.2110–1.3702) during the study period. In the breakdown of the medical costs, the proportion of injection drug fees increased most rapidly.

Conclusion: The high 30-day readmission rate in CRDMC was distinctive among the clinical outcomes. The proportion of medical costs for CRDMC in pediatric inpatients was high, although CRDMC accounted for only a small proportion of annual unique inpatients. Further support for CRDMC must be based on the unique characteristics of this population.

Background: Menarche timing may affect female health. While previous studies evaluated self-reported age at menarche reproducibility, they did not assess types of respondents. This study compared the reproducibility of age at menarche among self-responders and proxy respondents and assessed proxy-respondent reproducibility by relationship and survey age.

Methods: Data on age at menarche reported in both the 1969 and 1978 mail questionnaires among 9,043 females from the Life Span Study cohort of atomic bomb survivors were analyzed. The reproducibility of menarcheal age was assessed by the type of respondents, by proxy’s relationship to participant, and by age at the 1969 survey using Bland-Altman’s method and the intraclass correlation coefficient (ICC).

Results: Reproducibility was moderate (95% limits of agreement, −2.3 to 2.4 years; ICC 0.72; 95% confidence interval, 0.71–0.73). Both self-respondents (N = 6,664) and the total study population (N = 9,043) maintained moderate reproducibility even at older ages. Groups with proxy reports showed lower reproducibility than self-respondents, with spouse proxy reports showing highest reproducibility and parent proxy reports showing lowest reproducibility among proxy reports, although the comparisons are based on different survey ages in 1969.

Conclusion: This is the first study to evaluate menarcheal-age reproducibility between self- and proxy-reports using appropriate measures. Mail questionnaires at 9-year interval showed moderate reproducibility across all ages, including elderly self-respondents. Reproducibility varied by the respondent–target relationship, with spouse proxies showing highest and parent proxies showing lowest reproducibility among proxy reports. Additional data are required to establish appropriate methods for handling specific proxy responses.

Background: Older Japanese adults have the highest drowning mortality rates globally, likely due to in-home bathing customs. However, epidemiological evidence of preventive strategies based on national data is lacking. We aimed to describe the trends in bathtub drowning deaths (International Classification of Diseases, Tenth Revision code: W65) across Japan and explore factors that may reduce W65-coded deaths.

Methods: We collected the data of all W65-coded deaths that occurred at home from 1995 to 2020 using death certificates from the Ministry of Health, Labour and Welfare. The national age-adjusted mortality rates (AMRs) and prefecture-specific age-standardized mortality ratios (SMRs) were calculated. Data on demographic, socioeconomic, environmental factors, and nursing care services were obtained from the Japan Portal Site of Official Statistics. Mixed-effects analysis was used to examine the association between SMR and potential contributing factors at the prefecture level.

Results: We identified 99,930 W65-coded deaths at home, with the highest incidence among individuals aged 80–84 years, peaking in January. Since 2010, AMRs have consistently exceeded 3.0 per 100,000. An inverse association was found between SMR and the number of geriatric health service facilities and senior welfare centers per capita (coefficients per 1 standard deviation increase, −0.09; 95% confidence interval (CI), −0.13 to −0.05, P < 0.001 and −0.07; 95% CI, −0.11 to −0.02, P = 0.004, respectively), after adjusting for demographic, socioeconomic, and environmental factors.

Conclusion: Sustained high AMRs suggest that the rising death toll was not solely due to aging. Increased access to nursing care facilities may help prevent W65-coded deaths.

Background: Preventable behavioral risk factors account for approximately one third of mortality, morbidity, and disability worldwide. This study aims to quantify the interest in behavioral risk factors within major medical journals in 2022 and to derive trends over the past 30 years in the entire medical literature.

Methods: We analyzed the proportion of publications dealing with tobacco smoking, alcohol drinking, use of illicit drugs, excess body weight and physical activity among all the 1,128 articles published in the Journal of the American Medical Association, the British Medical Journal, the Lancet, and New England Journal of Medicine in 2022. A joinpoint analysis was conducted running in PubMed/MEDLINE specific search strings to evaluate trends over the last 30 years in the four journals and in the whole medical literature.

Results: In 2022, of all publications from the four considered medical journals, 2.8% dealt with tobacco smoking, 1.6% alcohol drinking, 1.1% use of illicit drugs, 3.8% excess body weight, 2.7% physical activity and 8.0% dealt with any behaviors. The joinpoint analysis on the whole medical literature showed that papers on modifiable risk factors significantly increased from 3.9% in 1993 to 6.2% in 2014 (annual percent change [APC]: between +1.83% and +4.09%), and subsequently decreased between 2014 and 2019 (APC −0.31%), with an acceleration thereafter (APC −2.41% in 2019–2022).

Conclusion: For the first time we quantified the volume of medical research focused on preventable behavioral risk factors. This appears to be limited and declining over the last decade. Research on primary prevention should be a priority to face the emergence of associated non-communicable diseases globally.

Background: Health status in old age can be influenced by financial disadvantages both at present and in earlier life stages; however, few studies have focused on the long-term individual patterns of financial disadvantage over the life course. This study examined the relationship between trajectories of financial disadvantage over the life course and depressive mood among community-dwelling older Japanese adults.

Methods: Data were obtained from the 2012 National Survey of the Japanese Elderly using a two-stage stratified random sampling method. The sample consisted of 1,324 adults aged ≥60 years. We retrospectively assessed financial disadvantage at four life-course benchmark periods: ≤18 years old, 25–35 years old, 35–50 years old, and current age. Depressive mood was measured using the 8-item Center for Epidemiologic Studies Depression Scale.

Results: We identified five distinct life-course financial disadvantage trajectories using group-based mixture modeling: “persistently affluent” (22.1%), “increasing affluence” (21.7%), “consistently modest” (28.0%), “decreasing affluence” (11.3%), and “persistently poor” (17.0%). A logistic regression analysis showed that people in the “increasing affluence” subgroup were less likely to have a depressive mood than those in the “persistently poor” subgroup, after adjusting for potential covariates, including current income and parental educational attainment. This association was more prominent in women than in men.

Conclusion: The experience of escaping from financial disadvantages may bolster the mental health of older adults, regardless of sociodemographic characteristics, health behaviors, and health conditions. The mental health benefits of increasing affluence throughout the life course may be even stronger than the benefits of experiencing persistent affluence.

Background: Encouraging older drivers to display the older drivers’ sign is one of the unique traffic safety policies for older drivers in Japan. The sign was discussed in light of ageism, but the potential merit of displaying it has not been investigated.

Methods: Using nationwide police-reported traffic crash data, we conducted a case-control study to examine whether displaying the sign is associated with reduced rear-end collision risk among drivers aged 70 years or older who were involved in car-to-car collisions from 2014 to 2023. The cases were those involved in rear-end collisions, the controls were those involved in angle collisions, and the exposure of interest was the sign display, which should be less often observed in the cases if the sign display is effective. The association was assessed with odds ratios adjusted for the time of crash and drivers’ sex and age group.

Results: Among 74,433 cases and 13,885 controls, the proportion of those displaying older drivers’ signs was 38% and 39%, respectively. By the time of crash and drivers’ sex and age group, the proportion tended to be slightly higher in the cases than in the controls. In both cases and controls, the proportion was higher among women, in older age groups, and during daytime. The crude and adjusted odds ratios were 0.99 (95% confidence interval [CI]: 0.95-1.02) and 1.08 (95% CI: 1.04-1.12).

Conclusion: Displaying the older drivers’ sign was not associated with reduced rear-end collision risk. Alternative interventions are needed to ensure their traffic safety.

Background

In 2023, a collaborative UNICEF–WHO group introduced the concept of small vulnerable newborns (SVNs) to improve the identification of newborns at increased risk of adverse outcomes and to guide more effective preventive strategies. However, global data on the prevalence of SVNs remains scarce. This study aimed to examine secular trends in the prevalence of SVNs and their three subgroups, namely term small for gestational age (SGA), preterm SGA, and preterm non-SGA, in the Japanese population.

Methods

We analyzed data from vital statistics including livebirths and stillbirths between 1997 and 2021. Secular trends in the prevalence of SVNs and their subgroups were assessed. In addition, we conducted regional analyses to explore associations with the distribution of medical resources.

Results

A total of 26,172,760 newborns were included. The overall prevalence of SVNs was 7.8% in 1997, peaked at 8.7% in 2005, and declined to 7.7% by 2021. This decline was primarily attributed to a reduction in term SGA births. In contrast, the prevalence of preterm SGA and preterm non-SGA remained largely unchanged. In 2021, the prevalence of term SGA, preterm SGA, and preterm non-SGA was 2.0%, 0.44%, and 5.3%, respectively. No significant association was found between the regional variation in the prevalence of SVNs and the distribution of medical resources.

Conclusion

The prevalence of SVNs in Japan has declined since 2005, mainly due to reduced term SGA births. Persistent rates of preterm subgroups highlight the ongoing burden of prematurity, underscoring the need for targeted strategies to improve neonatal outcomes.

Background: More research is needed to clarify the health effects of dietary carotenoid intakes, and this requires the use of high-quality assessments of habitual dietary intake. Cohort studies from the Tohoku Medical Megabank Organization included a self-administered food frequency questionnaire (TMM-FFQ) for community-dwelling adults. This study evaluated the validity of carotenoid intakes derived from the TMM-FFQ using serum carotenoid concentrations as the gold standard.

Methods: In Miyagi Prefecture, 88 men and 124 women aged ≥20 years voluntarily agreed to participate in the study and provided completed TMM-FFQs and blood samples in 2019 and 2021. Carotenoids examined included α-carotene, β-carotene, β-cryptoxanthin, and lycopene. Intraclass correlation coefficients (ICCs) were calculated to assess correlations between serum concentrations in 2019 and 2021. Spearman’s rank correlation coefficients were calculated to evaluate the correlations between energy-adjusted dietary carotenoid intakes from the TMM-FFQ in 2021 and the average serum carotenoid concentrations in 2019 and 2021, with correction for the attenuating effect of random within-individual variation.

Results: The ICCs between serum concentrations over the 2 years were >0.50 for all carotenoids. Among men, correlation coefficients were 0.33 for α-carotene, 0.42 for β-carotene, 0.50 for β-cryptoxanthin, and −0.09 for lycopene. Among women, the coefficients were lower than those for men, except for lycopene: 0.11 for α-carotene, 0.23 for β-carotene, 0.21 for β-cryptoxanthin, and 0.28 for lycopene.

Conclusions: The TMM-FFQ demonstrated reasonable validity for assessing intakes of α-carotene, β-carotene, and β-cryptoxanthin among men, but not among women, in the TMM cohort studies when using serum concentrations as the gold standard.

Background: The potential impacts of polygenic scores (PGS) on health-behavior changes are not fully understood. The Iwate PGS Assessment and Risk Communication Study aims to investigate the effects of reporting PGS-based risk for ischemic stroke on health behaviors.

Methods: Participants wishing to know their PGS-based ischemic stroke risk were recruited from health checkup venues for workers in Iwate Prefecture in 2023. Health checkup data, biospecimens, and questionnaire responses were collected for biochemical testing, genotyping, and storage in the Tohoku Medical Megabank integrated biobank. The risk was calculated using an integrative PGS model for East Asians. Participants were randomly assigned to two groups, and one group received their risk report as the intervention group. The impacts of the risk notification will be investigated in follow-up surveys.

Results: Of 3,599 workers, 2,088 participated in the study (consent rate, 58.0%). The demographic profile of the eligible 2,083 participants was as follows: 80.7% males, and dominance of participants aged 18–29 years (25.2%), in their 30's (25.3%), and in their 40's (24.7%). Two hundred participants (9.7%) had a risk of 1.0 as the reference; 57 (2.7%), 927 (44.7%), and 888 (42.9%) participants had 2.1–3.4-, 1.4–1.9-, and <1.0-fold that risk, respectively.

Conclusion: We collected health information and biospecimens from over 2,000 workers, and disclosed the PGS-based ischemic stroke risk. Behavioral effects will be evaluated 1 year after disclosure, with follow-up until 2030. As Japan's first large-scale PGS risk communication study, it will provide initial insights for implementing PGS in personalized preventive medicine.

Background: Brief measures of 24-hour movement behaviors are needed to easily evaluate their durations. The present study investigated the criterion validity and test-retest reliability of a brief self-report instrument to assess 24-hour movement behaviors.

Methods: A paper-based self-administered questionnaire was used to assess sleep, sedentary behavior (SB), light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with four items in 35 healthy adults. Participants wore a tri-axial accelerometer and answered the questionnaire on the final day of the accelerometry assessment and after 14 days. Spearman’s correlations of self-reported measures with their accelerometer-derived counterparts were assessed and median values compared by Mann-Whitney U-tests. Bland-Altman plots were employed to characterize differences in self-reported and device-measured time in the behaviors and their limits of agreement. Test-retest reliability was assessed using Intra-class correlation coefficients (ICCs).

Results: Moderate correlations with device measures for sleep, SB, and LPA for a typical and the past week (rho = 0.46 to 0.60) and low correlations for MVPA (rho = 0.33 to 0.47) were observed. Less duration of sleep and MVPA were reported compared with accelerometer-derived durations for the three recall periods (z = -3.9 to -2.5 and -4.0 to -3.5, respectively). The test-retest reliability for a typical week was fair-to-good or excellent for all the four behaviors (ICCs = 0.72 - 0.90).

Conclusion: Findings show acceptable validity and reliability of this questionnaire measure of 24-hour movement behaviors for typical week, past week and previous day recall periods.

Objectives:

This scoping review summarizes and evaluates evidence from Japan on prospective relationships of sedentary behavior (too much sitting as distinct from too little physical activity) with health outcomes, forming the basis for Japan’s new sedentary behavior guidelines. It also identified evidence gaps and provided recommendations for future public health guidelines.

Methods:

A systematic search was conducted in PubMed, Web of Science, CINAHL, and MEDLINE for English-language, peer-reviewed longitudinal studies on sedentary behavior and health outcomes in apparently healthy Japanese adults published between 2000 and 2023. The search strategy was developed based on sedentary behavior measures, study design, and study population. Two independent reviewers screened titles, abstracts, and full texts. Data were synthesized narratively, with a quality assessment performed.

Results:

Twenty-seven relevant studies were identified, all but one published after 2013. About half focused on middle-aged and older adults, primarily using self-report questionnaires. Many studies were large cohorts (>10,000 participants) with follow-ups of more than 10 years. Studies varied widely in physical activity indicators, confounders, time classifications, and cutoff values for sedentary behavior. The studies examined 29 health outcomes, primarily all-cause mortality, cancer incidence, and cancer mortality. Most studies reported at least partial evidence of harmful associations between sedentary behavior and health outcomes, though only eight were rated as good quality.

Conclusion:

There is sufficient evidence to support minimizing sedentary time to promote health in Japanese adults. However, due to the limited number of high-quality studies, the specificity and dose-response relationship between sedentary behavior and health outcomes remain unclear.

Background: One of the factors for not achieving a reduced salt diet may be the difficulties in screening individuals according to their quantitative salt consumption. Accordingly, we examined the performance of the simplified salt check sheet (13 items) as a quantitative tool for screening excessive salt intake by comparing with the salt intake amount measured by 24-hour urinary sodium (salt equivalent g/day) excretion.

Methods: One hundred fifty-four participants (57 males and 97 females) from Kanagawa, Tokyo, and Nara prefectures in Japan were included. In this study, which the design is a cross-sectional validation study, the salt intake amount was used as a diagnostic criterion, and corresponding receiver operating characteristic (ROC) curves were prepared based on the sensitivity and specificity of each score of the salt check sheet.

Results: The average salt intake were 13.5 and 10.2 g/day for males and females, respectively. When using the total score, among males, the area under the ROC curve (AUC) was moderate (0.702 [95% CI, 0.543-0.862]), confirming its value as a diagnostic tool for salt intake of ≥10 g/day. In females, the AUCs were low for any criteria. When score calculation item was limited to three that contributed to the higher salt intake in this population, the AUC for ≥10 g salt/day was moderate (0.700 [95% CI, 0.595-0.805]).

Conclusions: The salt check sheet was found to be useful in screening for excessive salt intake only in males. For females, it was suggested that it could be used only when three specific items are used.

Background:

Loneliness is prevalent among older adults and is linked to physical and mental health problems. Community social capital has been suggested to mitigate its impact, but its heterogeneity across socioeconomic groups was not explored

Method:

We analysed cross-sectional data from the 2019 Japan Gerontological Evaluation Study (JAGES) with 24,206 participants aged 65 years or older. Loneliness was measured using UCLA’s 3-item scale, and community social capital was assessed by civic participation, social cohesion, and reciprocity. Modified Poisson regression models were used, adjusting for sociodemographic factors and individual responses to the questions on social capital. Interaction effects of gender, education, and income were examined.

Results:

Higher levels of community social cohesion (PR = 0.84, 95% CI: 0.75-0.94) and community reciprocity (PR = 0.64, 95% CI: 0.51-0.80) were inversely associated with loneliness. The relationship between community civic participation and loneliness varied by educational attainment. Interaction analysis indicated that individuals with higher education levels (≥ 13 years) who engaged in community civic participation had a lower prevalence of loneliness (PR = 0.74, 95% CI: 0.57–0.95) compared to those with lower education levels. No clear interactions were observed for gender or income.

Conclusions:

Community social capital, particularly social cohesion and reciprocity, was associated with lower levels of loneliness among older adults. The effect of civic participation differed by education, showing a stronger negative association among individuals with higher education levels (≥ 13 years). Tailored interventions accounting for educational backgrounds are needed while promoting social capital universally.

Background: Non-random participation can undermine the representativeness of seroepidemiological surveys. Despite their critical role in estimating disease spread during pandemics, non-response bias and methods to correct it require further investigation. This study aimed to examine sociodemographic characteristics and COVID-19-related factors influencing participation in a seroepidemiological survey.

Methods: We analyzed data from a national COVID-19 seroepidemiological survey in Japan between December 2022 and March 2023. We performed multivariable logistic regression analyses to estimate adjusted odds ratios (AOR) and their confidence intervals (CIs) after variable selection with the Group Least Absolute Shrinkage and Selection Operator.

Results: Among 6,091 participants, factors associated with higher odds of seroepidemiological surveys participation included being female (AOR 2.08 [95% CI, 1.25-3.47]), living in larger households versus living alone (two: 2.34 [1.20-4.55]; four or above: 2.05 [1.03-4.06]), higher education levels versus junior high school education (high school: 2.66 [1.06-6.15]; junior colleges, technical colleges, vocational schools: 5.51 [1.94-15.07]; university and above: 3.30 [1.26-7.98]), and having a higher household income versus earning <2 million yen (2–4 million yen: 3.32 [1.52-7.33]; 4–6 million yen: 2.73 [1.2-6.23], ≥6 million yen: 4.51 [1.91-10.59]). Lower seroepidemiological survey participation odds were observed in those hesitant or unwilling to vaccinate (0.16 [0.09-0.29]) and those perceiving a higher COVID-19 positivity rate among close contacts (0.98 [0.98-0.99]).

Conclusions: Education, income, household size, sex, vaccination status, and perceived infection risk influenced seroepidemiological survey participation. The findings highlight the need to account for non-response bias using weighted methods like inverse probability weighting.

Background: The Ministry of Health, Labour and Welfare in Japan has published a meal-based dietary guideline (Healthy Meal); however, its relationship with health outcomes remains unclear. This observational study examined the association between adherence to Healthy Meal and all-cause and cause-specific mortalities.

Methods: We analyzed data from the Japan Public Health Center-based Prospective Study (JPHC Study) with a mean follow-up of 19.0 years, including 40,222 men and 47,350 women aged 45–75 years with no history of cancer, stroke, ischemic heart disease, chronic liver disease, or kidney disease. Adherence to Healthy Meal was scored using dietary intake from a validated food frequency questionnaire. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortalities across score quartiles.

Results: A higher Healthy Meal adherence score was significantly associated with a lower risk of all-cause mortality. The multivariable-adjusted HRs (95% CIs) for the highest versus the lowest adherence group were 0.86 (0.82–0.91, p<0.001 for trend) in men and 0.92 (0.87–0.98, p=0.005 for trend) in women. Significant associations with a lower risk of cerebrovascular disease and respiratory disease mortalities were observed in both sexes. In contrast, significant associations were observed for cancer, cardiovascular disease, and heart disease mortalities in men only.

Conclusions: Higher adherence to the Japanese meal-based dietary guideline was associated with a lower risk of all-cause, cerebrovascular disease, and respiratory disease mortalities in Japanese men and women, and cancer, cardiovascular disease, and heart disease mortalities in men only.

Background

Insulin resistance in adipocytes, manifested as high basal circulating free fatty acid (FFA) is thought to contribute to the development of type 2 diabetes mellitus (T2DM). However, the association between adipocyte insulin resistance (Adipo-IR) index and T2DM has rarely been explored in prospective studies. We examined this association in a middle-aged Japanese workers’ cohort. Since the association may differ according to the degree of overall adiposity, the analysis was stratified by the presence of overweight/obesity defined with body mass index (BMI).

Methods

A total of 3,257 subjects (men 2501, women 756) aged 35-66 years were followed-up for up to 17 years. T2DM incidence was defined as fasting blood glucose level ≥ 126 mg/dL, glycated hemoglobin level ≥ 6.5 %, or self-reported initiation of glucose-lowering medications. Adipo-IR was calculated as the product of FFA (mmol/L) and insulin (pmol/L) obtained from baseline fasting blood samples and divided into sex- and BMI category (<25 or ≥25 kg/m²)-specific tertiles. Cox-proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for age, BMI, smoking status, physical activity, drinking habit and family history of diabetes.

Results

During a median of 14.6 years of follow-up, 365 developed T2DM. Compared with the lowest tertile, T2DM risk was significantly increased among the highest tertile category in overweight/obese men (HR: 2.94, 95% CI, 1.76-4.90) and women (HR: 4.24, 95% CI, 1.08-16.61).

Conclusion

Adipo-IR was positively associated with T2DM risk in overweight/obese men and women.

Background: Resilience is an important ability in reducing subsequent health risks from poverty. This study aimed to examine whether reading books in fourth grade boosts resilience in sixth grade and whether poverty status modifies the association.

Methods: We used a part of longitudinal data from 2018 to 2020 from the Adachi Child Health Impact of Living Difficulty (A-CHILD) study. In this analysis, we used all fourth-grade elementary school students and their caregivers’ follow-up data (n = 3,136, 9- to 10-year-olds, 49.6% boys, follow-up rate =87%). Poverty and child reading books in fourth grade were assessed at baseline. Child resilience in fourth and sixth grade was assessed by caregivers using the Children’s Resilient Coping Scale.

Results: In fourth grade, 20% of children read no books, while 15% read 4 or more books per week. Children who read more books at baseline became more resilient in sixth grade, even after adjustment of resilience in fourth grade. Poverty in fourth grade was associated with lower resilience in both fourth and sixth grade; however, when stratified by poverty status, the number of reading books was significantly associated with higher resilience only among children in poverty (e.g., coefficient=5.13, 95% confidence interval (CI): 1.20 to 9.06 for ≥4 books vs. none).

Conclusions: For elementary school children in Japan, reading books boosts resilience, especially among children in poverty. Educational policy on reading books during elementary school may be important to address child poverty.