The ISPOHC was initiated in Shanghai to address the need for a comprehensive and longitudinal study on iodine nutrition and its effects on maternal and offspring health. The findings based on the Shanghai population can serve as a reference for other megacities experiencing significant dietary changes simultaneously. ISPOHC utilized a stratified cluster random sampling design, enrolling 5099 pregnant women from all 16 districts of Shanghai. The survey has been conducted in three phases. Data collected at different time points include health status, living habits, dietary intake, birth, feeding, early development, anthropometric measurements, and biomarkers, allowing for an in-depth evaluation of iodine nutrition's impact on offspring development. Data were collected through a combination of questionnaires, home visits, anthropometric measurements, and biological sample collection. The integration of detailed food investigation and on-site weighing of household seasonings provides a more precise assessment of dietary iodine intake, particularly iodized salt consumption, distinguishing this study. The study has provided significant insights into the relationship between iodine nutrition during pregnancy and various health outcomes.

Purpose: New long-term care insurance (LTCI) certifications and mortality are key outcomes in cohort studies involving older adults; however, the coronavirus disease 2019 (COVID-19)’s comprehensive impacts on these outcomes remain underexplored. We examined the pandemic’s impact on new LTCI applications and all-cause mortality in a metropolitan cohort.

Methods: In 2016, 15,500 individuals aged 65–84 years were randomly selected through stratified sampling from Ota City, Tokyo. LTCI and death records were tracked through December 2023; the monthly LTCI applications and all-cause deaths per 10,000 people were calculated. The COVID-19 pandemic period was defined as beginning in March 2020, after the World Health Organization Director-General characterized the situation as a pandemic on March 11, 2020. Interrupted time-series segmented regression analysis was used to compare trends pre- (January 2018–February 2020) and post-pandemic onset (March 2020–December 2023).

Results: From January 2018 to December 2023, 4083 new LTCI applications and 2457 deaths were recorded. New monthly LTCI applications showed a modest upward trend pre-pandemic (0.4 per 10,000 people, 95% confidence interval [CI]: 0.1–0.8), declined sharply at the pandemic’s onset (-9.6 per 10,000 people, 95% CI: -16.0 to -3.2), and subsequently increased at a higher rate than pre-pandemic levels (0.8 per 10,000 people, 95% CI: 0.6–1.0). Monthly all-cause deaths remained stable before and immediately after the pandemic's onset but rose slightly in the post-pandemic period (0.3 per 10,000 people per month, 95% CI: 0.2–0.5).

Conclusions: The COVID-19 pandemic influenced both new LTCI applications and all-cause mortality in this study. These impacts should be carefully considered in cohort studies examining these outcomes.

Background: The fecal immunochemical test (FIT) has been widely used in colorectal cancer (CRC) screening, yet the practical performance of FIT combined with questionnaire-based risk assessment (QRA) remains undetermined. Moreover, risk factors for distinct CRC precursors identified in screening have been rarely compared.

Methods: This study was based on a population-based CRC screening in China, with 2,120,340 participants completing both FIT and QRA. Those with positive FIT or high QRA scores were recommended for colonoscopy. We reported the compliance, detection rate, and colonoscopy workload according to FIT and QRA results. We also explored risk factors for conventional adenomas and serrated polyps.

Results: The compliance rate of colonoscopy in the subgroup of FIT (+) and QRA (+) was 41.4%, higher than the rates in FIT (+) and QRA (−), as well as FIT (−) and QRA (+), which were 38.7% (P < 0.001) and 16.4% (P < 0.001), respectively. The corresponding detection rates of advanced neoplasia were 18.2%, 13.2%, and 9.3% (all P < 0.001), respectively. Moreover, the required numbers of colonoscopies to detect one advanced neoplasia in the three subgroups were 5.5, 7.6, and 10.8, respectively. Increased body mass index, smoking, alcohol consumption, red meat intake, and type 2 diabetes were associated with higher risk of advanced adenomas and advanced serrated polyps, whereas vegetable intake was inversely associated with advanced adenomas.

Conclusion: FIT and QRA can synergistically identify individuals at high risk of colorectal advanced neoplasia, with those testing positive for both deserving immediate attention. Modifiable factors were identified to complement screening for preventing CRC precursors.

Background: There is still uncertainty regarding the association between maternal serum levels of retinol-binding protein 4 (RBP4) and pregnancy outcomes. This study aimed to determine the association between RBP4 levels and incidence of small/large for gestational age (SGA/LGA) infants among the Chinese population.

Methods: This was a retrospective study of 11,854 pregnant women who delivered at Changzhou Maternal and Child Health Care Hospital between 2016 and 2017 and whose serum RBP4 levels were measured at the time of admission. The incidence of SGA/LGA deliveries was retrieved from the medical records of the participants.

Results: Maternal RBP4 levels in the second, third, and fourth quartiles (28.8–34.0, 34.1–40.0, and >40.0 mg/L, respectively) were associated with lower birthweights relative to those in the first quartile (<28.8 mg/L), with estimated average decreases of 51.30 g (95% confidence interval [CI], −70.51 to −32.10), 86.86 g (95% CI, −106.50 to −67.22) and 124.08 g (95% CI, −144.51 to −103.64), respectively (P for trend <0.01). Pregnant women in the fourth quartile for RBP4 levels had a greater SGA risk (odds ratio [OR] 2.14; 95% CI, 1.72–2.65) and lower LGA risk (OR 0.53; 95% CI, 0.45–0.63) than those in the first quartile after controlling for demographic variables, gestational age, pregnancy complications, and other laboratory results. The sensitivity analysis indicated the consistency of these findings.

Conclusion: High RBP4 levels in late pregnancy are associated with an increased SGA risk and decreased LGA risk, indicating that serum RBP4 levels at the time of admission for delivery could be a promising predictor of SGA/LGA delivery.

Background: Community social capital is associated with various health outcomes; however, its impact on mortality is not fully understood, particularly in non-Western settings. This study examined the association between community-level social capital and all-cause mortality among community-dwelling older Japanese adults.

Methods: The baseline data were obtained from a 2015 questionnaire survey for all 132,005 residents aged ≥65 years without long-term care insurance certification in Adachi Ward (consisting of 262 small districts) of the Tokyo metropolitan area. We measured two aspects of social capital: neighborhood cohesion as cognitive social capital and neighborhood network as structural social capital. For district-level social capital, we aggregated the individual responses of neighborhood cohesion and neighborhood network in each district.

Results: A total of 75,338 were analyzed. A multilevel survival analysis with an average follow-up of 1,656 days showed that higher district-level neighborhood cohesion was associated with a lower risk of all-cause mortality in men (hazard ratio 0.92; 95% confidence interval [CI], 0.84–0.99 for the highest quintile and 0.91; 95% CI, 0.82–0.99 for the second, compared to the lowest), but not in women. This association was more pronounced in men aged 65–74 years.

Conclusion: This study provides valuable insights from the Asian population. Men, who typically have fewer social networks and support systems than women, could receive more benefits from residing in a cohesive community, which may contribute to their longevity. These findings support public health strategies that bolster community social capital as a means of archiving longevity among older men, underscoring the importance of social integration in aging societies.

Background: The Tohoku Medical Megabank Project has initiated the Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study) including genomic and omics investigations and conducted a self-administered food frequency questionnaire with the response option “constitutionally unable to eat or drink it” for individual food items (TMM-FFQ) for pregnant women. This study evaluated the validity of the TMM-FFQ among pregnant women.

Methods: Participants comprised 122 pregnant women aged ≥20 years residing in Miyagi Prefecture who completed weighed food records (WFRs) for 3 days as reference intake and the TMM-FFQ during mid-pregnancy. Correlations between nutrient or food group intakes based on the WFR and the TMM-FFQ were calculated using Spearman’s rank correlation coefficients (CCs), adjusting for energy intake and correcting for random within-individual variation of WFR. Cross-classification was also conducted according to quintiles using the WFR and TMM-FFQ data.

Results: The percentages of participants who chose the “constitutionally unable to eat or drink it” option were >3% for seven food and drink items. CCs were >0.30 for 31 nutrients; the median across energy and 44 nutrients was 0.41. CCs were >0.30 for 14 food groups; the median across 20 food groups was 0.35. The median percentages of cross-classification into exact plus adjacent quintiles and extreme quintiles were 63.1% and 3.3% for energy and nutrients and 61.9% and 4.1% for food groups, respectively.

Conclusion: The validity of the TMM-FFQ compared with the WFR was reasonable for certain nutrients and food groups among pregnant women in the TMM BirThree Cohort Study.

Background: Few have examined the condition of subjective daytime sleepiness in workers and its relation to their work productivity. This study aimed to clarify the association between the presence of subjective daytime sleepiness and work productivity measures, including presenteeism and absenteeism, as well as factors related to the presence of the symptom in daytime workers.

Methods: This cross-sectional study included 17,963 daytime workers who attended the annual medical check-up. They were categorized into four groups; the daytime sleepiness group was defined as having only subjective daytime sleepiness, the insomnia group as having only insomnia symptoms, the combination group as having both subjective daytime sleepiness and insomnia symptoms, and the healthy group as having no sleep complaints. This study used demographics, health status, workplace, work productivity, and sleep items included in the self-reported medical check-up questionnaire.

Results: The combination group had significantly worse presenteeism than other groups. The daytime sleepiness and insomnia groups had significantly worse presenteeism than the healthy group. The results of absenteeism were the same as presenteeism. Factors related to the positivity for subjective daytime sleepiness were presence of psychiatric disease, the positivity for habitual snoring and/or witnessed apnea, shorter sleep duration on workdays, long working hours, female sex, living alone, the amount of social jetlag, and younger age.

Conclusion: Subjective daytime sleepiness, not just insomnia symptoms, has a significant negative impact on work productivity, and both workplace and individual approaches should not be ignored for addressing subjective daytime sleepiness among daytime workers.

Background: The discomfort experienced due to residual tobacco smoke, a form of thirdhand smoke exposure brought into workplaces by smokers, and its health impacts on non-smokers have been inadequately investigated. This study explored associations between non-smokers’ discomfort and work performance and mental health.

Methods: This observational internet-based survey was conducted in 2021 as part of the Japan Society and New Tobacco Internet Survey. Participants comprised 6,519 adult workers without firsthand or secondhand smoking. Work performance and mental health were evaluated using the Work Functioning Impairment Scale (WFun) and Kessler Psychological Distress Scale (K6), respectively. The proportion of participants who experienced discomfort from the residual tobacco smoke in their workplace by smokers in the previous year was calculated according to the workplace’s smoke-free policy, and the difference was assessed using the χ² test. The association between such discomfort and WFun and K6 scores was examined using univariable and multivariable logistic regression analyses.

Results: Among respondents, 17.1% reported experiencing discomfort due to the residual tobacco smoke. A strict smoke-free workplace policy was associated with a lower proportion of respondents experiencing such discomfort (p<0.001). Those who experienced discomfort more frequently had significantly higher scores on the WFun (“never” 15.5%, “sometimes” 21.3%, “frequently” 26.2%) and K6 (“never” 37.8%, “sometimes” 48.2%, “frequently” 50.8%). Adjusting for potential covariates in multivariable analyses did not change this result.

Conclusion: Discomfort from thirdhand smoke was associated with worse work performance and mental health problems. Promotion of strict smoke-free workplace policies is required to reduce such experiences.

Background: We examined the association between the COVID-19-specific prefectural bed utilization rate and in-hospital mortality during the first three years of the pandemic in Japan.

Methods: This nationwide study included 58,175 COVID-19 patients from the COVID-19 Registry Japan, hospitalized between May 1, 2020 and November 30, 2022. Based on the weekly COVID-19-specific bed utilization rate in each prefecture at diagnosis, patients were categorized into four groups (< 25%, 25% to < 50%, 50% to < 75%, and ≥ 75%). Odds ratios (ORs) were estimated by fitting a generalized linear mixed model with prefecture as a random intercept and adjusting for covariates (age, gender, body mass index, smoking and drinking status, and comorbidities). Additional analyses according to age group, gender, and wave of the pandemic were conducted.

Results: We observed 2312 (4.0%) all-cause in-hospital deaths. All-cause in-hospital mortality increased with higher COVID-19 bed utilization rates at diagnosis (OR for multivariable model 1.35, 95% confidence interval [CI] 1.19-1.54 for 25% to <50%; 1.89, 1.66-2.16 for 50 to <75%; 2.16, 1.80-2.58 for ≥75%; P for trend<0.0001). Stronger associations were noted among the younger population (aged <70 years, OR: 3.18, 1.96-5.19) and during the fourth (March 1-June 30, 2021, OR: 3.81, 2.13-6.80) and sixth pandemic waves (January 1-Jun 30, 2022, OR: 2.67, 1.68-4.23).

Conclusions: Our results emphasize that preventing hospital bed shortages during outbreaks is an important public health strategy to reduce the associated mortality, particularly when new strains emerge and in younger people.

Background This study aimed to assess a clinical relevance of three-dimensional occupational stress (job stressor score [A score], psychological and physical stress response score [B score], and social support for workers score [C score]) of the Brief Job Stress Questionnaire (BJSQ) in the national stress check program in Japan to irregular menstruation.

Methods The present retrospective cohort study included 2,078 female employees aged 19–45 years who had both annual health checkups and the BJSQ between April 2019 and March 2022 in a national university in Japan. The outcome was self-reported irregular menstruation measured at annual health checkups until March 2023. A dose-dependent association between BJSQ scores and incidence of irregular menstruation was examined using Cox proportional hazards models to calculate multivariable-adjusted hazard ratios (HRs) of four quantile (0–49% [Q_0–49], 50–74% [Q_50–74], 75–89% [Q_75–89], and 90–100% [Q_90–100]) of the BJSQ scores.

Results During 2.0 years of the median observational period, 257 (12.4%) women reported irregular menstruation. B score, not A or C scores, was identified as a significant predictor of irregular menstruation (adjusted HR [95% confidence interval] of A, B, and C scores per 1 standard deviation: 1.06 [0.89–1.27], 1.35 [1.15–1.57], and 0.93 [0.80–1.08], respectively). Women with higher B score had a significantly higher risk of irregular menstruation in a dose-dependent manner (adjusted HR [95% confidence interval] of Q_0–49, Q_50–74, Q_75–89, and Q_90–100: 1.00 [reference], 1.38 [1.00–1.90], 1.48 [1.00–2.18], and 2.18 [1.38–3.43], respectively).

Conclusions Psychological and physical stress response predicted irregular menstruation.

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, 1.11; 95% credible interval [CI], 1.07-1.14), respiratory infections (aOR, 1.16; 95% CI, 1.11-1.21), gastrointestinal diseases (aOR, 1.19; 95% CI, 1.12-1.27), asthma (aOR, 1.06; 95% CI, 1.02-1.10), and allergic rhinitis (aOR, 1.02; 95% CI,1.00-1.04). Overweight/obesity at age 5.5 years also increased with higher ADI (aOR, 1.08; 95% CI, 1.03-1.11). Higher ADI was inversely associated with Kawasaki disease (aOR, 0.91; 95% CI, 0.83-0.998), though not robust in sensitivity analysis. Geographic clustering was observed for all outcomes, particularly at municipality level.

Conclusions

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: Evidence of post-COVID-19 condition (PCC) in the Alpha- and Delta-variant dominant waves is limited.

Methods: In a nationwide multicenter cohort study in collaboration with 20 hospitals, we collected data using self-administered questionnaires and electronic medical records of participants aged 20 or more diagnosed with COVID-19, hospitalized between April 1, 2021 and September 30, 2021, and discharged alive. Descriptive statistics were analyzed for PCC and mental health (HADS anxiety and depression scores), comparing Alpha- and Delta-variant dominant waves.

Results: We analyzed 1,040 patients (median age, 57 [IQR 49–66] years; men, 66.2%). Of the respondents, 45.4% had at least one PCC symptom 1 year after infection. The common symptoms included dyspnea (20.7%), fatigue/malaise (17.6%), muscle weakness (15.4%), decrease in concentration (13.4%), and sleep disorder (13.3%), followed by brain fog (8.4%). Among patients with PCC, 14.0% had anxiety (HADS-Anxiety ≥11), and 18.6% had depression (HADS-Depression ≥11), with four times higher proportions than those without PCC; only small variations by age, sex, and waves were observed. Associated factors for PCC were age 40 years or over, women, severity of COVID-19 during hospitalization, ex-smokers who quit smoking before COVID-19 infection and being infected during the Delta-variant dominant wave.

Conclusion: The study described the prevalence of PCC, associated factors, and mental health of COVID-19 survivors hospitalized during the Alpha- and Delta-variant dominant waves in Japan. Further follow-up will be conducted to examine the longer-term impact of COVID-19 on PCC, complications, daily life, and socioeconomic status.

Background: Use of novel tobacco products, such as heated tobacco products, has recently increased as a result of being promoted less harmful alternatives to cigarettes. The impact of the coronavirus disease 2019 (COVID-19) pandemic on tobacco use may differ depending on the type of tobacco.

Methods: We longitudinally investigated changes in tobacco use over a 1-year period using internet-based and self-reported questionnaires among Japanese aged 15 to 79 years. The study was conducted from 2019 to 2021, with participants before the COVID-19 pandemic in February 2020 as the pre-pandemic group and participants after that as the pandemic group. Accounting for population bias, we used sampling probability weighting referring to the nationwide data. The association between cessation and the COVID-19 pandemic was evaluated separately for each type of tobacco using logistic regression analysis.

Results: After conducting sampling probability weighting, 1,920 were in the pre-pandemic group and 2,681 were in the pandemic group. More participants in the pandemic group than in the pre-pandemic group achieved cessation after 1 year (13.8% vs 10.2%, P < 0.001). Dual users were more likely to quit during the pandemic than pre-pandemic (adjusted odds ratio [aOR] 2.56, P < 0.001), whereas exclusive novel tobacco users were less likely to quit during the pandemic (aOR 0.66, P = 0.041). Tobacco cessation was more frequently achieved among those who had intended to quit at baseline survey among conventional tobacco users (aOR 1.77, P < 0.001) and dual users (aOR 2.52, P < 0.001); however, this trend was not observed among novel tobacco users (aOR 1.49, P = 0.090).

Conclusion: Conventional and novel tobacco use patterns varied in response to the COVID-19 pandemic.

Background: The interaction and substitution effects of physical activity (PA) and sitting time (ST) living in non-western countries have not been well investigated. This study aimed to examine the association of moderate-to-vigorous physical activity (MVPA) and ST with disability and mortality in older adults.

Methods: This prospective study analyzed data from 10,164 adults over 65 who participated in the Kyoto-Kameoka study in Japan. We evaluated MVPA and ST using the validated International Physical Activity Questionnaire-Short Form. Participants were categorized into four groups based on their levels of MVPA (150 min/week) and ST (300 min/day): low MVPA/high ST, low MVPA/low ST, high MVPA/high ST, and high MVPA/low ST. Outcomes were gathered between July 30, 2011, and November 30, 2016.

Results: Over a median follow-up of 5.3 years (45,461 person-years), 2,273 disability cases were documented. The low MVPA/high ST groups were associated with higher disability risk than those in the high MVPA/low ST groups (hazard ratios [HRs], 1.52; 95% confidence interval [CI], 1.31–1.75), and the interaction between MVPA and ST accounted for 48.5% of the relative excess risk of disability in the low MVPA/high ST group (p for interaction = 0.006). Replacing daily 10 min of ST with 10 min of MVPA was associated with a reduced risk of disability (HR, 0.980; 95% CI, 0.971–0.989) and all-cause mortality (HR, 0.975; 95% CI, 0.962–0.988).

Conclusions: These findings indicate that even a small substitution of ST with MVPA could help lower both the risk of disability and mortality.

Background: Poor dietary habits are a significant changeable factor contributing to negative health effects; however, the connection between variations in dietary diversity over time and mortality remains uncertain. This study aimed to evaluate the association between longitudinal changes in the dietary diversity score (DDS) and mortality in Japanese adults.

Methods: This prospective study included 20,863 adults (13,144 women, 7,719 men) aged 40-79 years from the Japan Collaborative Cohort Study. The DDS was evaluated twice, once at baseline and again 5 years later, using a validated food frequency questionnaire that assessed 33 food items. Participants were classified into four groups based on mean DDS: baseline low DDS/5 years later low DDS (n=7,866; Low/Low group), baseline low DDS/5 years later high DDS (n=2,951; Low/High group), baseline high DDS/5 years later low DDS (n=3,000; High/Low group), and baseline high DDS/5 years later high DDS (n=7,046; High/High group). Survival data were collected until 2009, and hazard ratios (HRs) for mortality were calculated using a Cox proportional hazards model.

Results: During a median follow-up of 14.8 years (256,277 person-years), 2,995 deaths were documented. After adjusting for confounders, participants in the High/High group had a lower HR for mortality from all causes (HR:0.82; 95% confidence interval [CI]:0.74–0.91) and cardiovascular disease (HR:0.81; 95% CI:0.67–0.98) than those in the Low/Low group. Similar associations were observed with dairy, soy, and vegetables/fruits, but they were validated exclusively in women.

Conclusions: This study showed that maintaining a higher DDS may be associated with lower mortality in women.

Background: Coronavirus disease 2019 (COVID-19) in children is often asymptomatic, posing challenges in detecting infections. Additionally, factors contributing to infection remain poorly understood. This study aimed to investigate trends in anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antibody seroprevalence, the relationship between seroprevalence and parental perception of child infection, and factors related to COVID-19 in children.

Methods: In December 2020, 355 children aged 6–12 years in one elementary school were enrolled in the study. The anti-SARS-CoV-2 nucleocapsid antibody seroprevalence was assessed, and questionnaires were administered annually for 3 years. Parents’ perceptions of infection and factors contributing to infection were examined.

Results: The seroprevalence was 0.6%, 2.2%, and 60.9% in the first, second, and third years, respectively. The third-year seroprevalence among children reported as ‘infected,’ ‘not tested but had symptoms,’ and ‘not infected’ by parents was 97.3%, 83.3%, and 35.7%, respectively. Increased odds of seropositivity at the third-year measurement were observed in lower grades (adjusted odds ratio [aOR] 2.79 compared with higher grades) and in children more likely to play with others (aOR 3.97 for ‘somewhat’ and aOR 2.84 for ‘often,’ compared with ‘rarely’). No significant associations with seropositivity were found for sex, siblings, body mass index, serum 25-OH vitamin D₃ concentration, or sleep duration.

Conclusion: The Omicron variant outbreak from the end of 2021 led to a sharp increase in seroprevalence among children, with many unaware of their infection. Frequent play with others may facilitate transmission in children. These data provide useful information for developing countermeasures against COVID-19 and other future pandemics.

Background: While evidence from Western countries links low-to-moderate alcohol consumption to a lower risk of type 2 diabetes mellitus (T2D), findings have been inconsistent in Asia. Since T2D in Asia involves both insulin resistance and deficient insulin secretion, both of which are differently affected by alcohol, we prospectively examined whether the association differs according to body mass index (BMI) categories among the Japanese.

Methods: Participants were 31,524 health checkup examinees (26,819 males and 4,705 females aged 20-64 years) who were free from diabetes at baseline. Self-reported data on alcohol use were used to estimate the average daily alcohol consumption at the baseline. Incident diabetes was identified at annual checkups during the follow-up period. A Cox proportional hazards model was used to estimate hazard ratios and 95% confidence intervals.

Results: During a median follow-up of 12.0 years, 3,527 male and 287 female participants developed T2D. The association between alcohol consumption and T2D risk differed markedly by BMI in both sexes. Among males, low- and moderate-level alcohol consumption was associated with a lower T2D risk in individuals with BMI ≥25.0 kg/m², whereas consumption at a level of 2 go/day (approximately 46 g ethanol) was linked to an increased T2D risk in those with BMI ≤22.0 kg/m². In females, similar patterns were observed, although confidence intervals were broad due to smaller sample size.

Conclusions: In Japan, low-to-moderate alcohol consumption may lower T2D risk in those with excess body weight, while high alcohol consumption may increase T2D risk in those with lower BMI.

Background: Several studies reported an association between the number of teeth and the incidence of hip fractures in observational studies, mainly in middle-aged adults. This retrospective cohort study aimed to clarify the association between the number of teeth and the incidence of hip fractures.

Methods: In this retrospective cohort study, a total of 256,772 participants aged 75 years or older who underwent public dental checkups in Japan were evaluated. Exposure in this study was the number of teeth, with a maximum number of 28, excluding third molars. Outcome measures were the incidence of hip fractures needing surgery, using the Japanese procedure codes in medical claims.

Results: A total of 190,998 participants met the inclusion criteria and were available for analysis. Adjusted Fine and Gray models identified a significant association between the number of teeth, including sound, filled, and decayed teeth, and the incidence of hip fractures among women but not for men. The continuous net reclassification improvement (NRI) of the sound and filled teeth count model increased by 0.078 compared with that of the sound, filled, and decayed teeth count model among women.

Conclusions: The number of sound and filled teeth predicted the risk of hip fractures in women, whereas no association was observed between the number of teeth and hip fractures in men.

Background

Studies have shown that informal caregiving is associated with an increased risk of cardiovascular diseases. However, there is limited evidence on the mechanisms involved. To fill this knowledge gap, we investigated the association of informal caregiving with changes in health-related behaviors.

Methods

We analyzed a nationally representative sample aged 50–59 years as of 2005 using fifteen waves of the Longitudinal Survey of Middle-Aged and Older Adults, conducted between 2005–2019. We investigated the association between the change in informal caregiving status and the change in health-related behaviors, including (1) heavy drinking, (2) smoking, (3) no exercise habits, and (4) no attendance at annual health checkups. We used multivariable logistic regression models with correlated random effects, adjusting for individual-level time-invariant characteristics.

Results

Among 268,165 observations from 30,530 participants (median age 55 [interquartile range 52–57] at baseline; 51.6% women), 32,164 (12.0%) observations from 10,224 individuals provided informal care. After adjusting for potential confounders, informal caregiving was associated with higher probabilities of deteriorating health-related behaviors, including heavy drinking (adjusted odds ratio [aOR] 1.16; 95% confidence interval [CI] 1.03–1.32; adjusted p=0.032) and no exercise habits (aOR 1.09; 95%CI 1.04–1.15; adjusted p<0.001). We observed similar patterns for smoking (aOR 1.12; 95%CI 1.001–1.26; adjusted p=0.053) and no attendance at health checkups (aOR 1.05; 95%CI 0.999–1.10; adjusted p=0.053).

Conclusion

This study showed that the transition into informal caregiving was associated with deteriorating cardiovascular-related health behaviors in Japan. These findings highlighted the importance of continued efforts to prevent the deterioration of caregivers’ health-related behaviors.

Background: We launched the Wako Cohort Study in 2023 to identify individual and socio-environmental factors related to the extension of healthy life expectancy and the reduction of health disparities among community-dwelling adults and to develop health promotion and care prevention strategies. This study profile aims to describe the study design and participants’ profile at baseline.

Methods: The Wako Cohort Study is a prospective study of community-dwelling adults aged ≥ 40 years living in Wako City, Saitama Prefecture, Japan. The Wako Cohort Study consists of two surveys: a mail-in survey for persons aged ≥ 40 years and a face-to-face assessment (on-site survey) for those aged ≥ 65 years. The survey items were designed considering the following points: 1) life course perspective (transition from middle to old age in the life course), 2) health indifference, and 3) employment in older age.

Results: A total of 8,824 individuals participated in the mail-in survey (2,395 persons aged 40–64 years and 6,429 aged ≥ 65 years). Of those aged ≥ 65 years who returned the mail survey, 1,004 participated in the subsequent on-site survey. Men aged ≥ 65 years tended to have higher health interests than those aged 40–64 years; however, this was not true for women. In the mail-in survey, 30.4 % of those aged ≥ 65 years were employed.

Conclusions: The Wako Cohort Study is expected to provide new insights into the development of strategies to extend healthy life expectancy and reduce health disparities in Japan.

Background: Healthy life expectancy (HLE) is a population health indicator that is widely used in developed countries, but little is known about its relationships with combinations of non-communicable disease risk factors. This study was conducted to examine HLE at age 65 according to combinations of blood pressure levels, body mass index, smoking status, and diabetes mellitus (DM) in a Japanese population.

Methods: In a nationwide cohort study (NIPPON DATA90), data on these risk factors were obtained from participants in 1990 through physical examinations, blood tests, interviews, and questionnaires. Subsequently, participants aged ≥65 years underwent surveys on activities of daily living in 1995 and 2000, and multistate life tables were used to calculate combination-specific HLEs and their 95% confidence intervals (CIs).

Results: The study population comprised 6,569 participants (men: 2,797; women: 3,772) who were followed-up until 2010. HLE at age 65 in men with grade II/III hypertension, obesity, current smoker status, and DM (HLE: 12.9 years, 95% CIs: 12.9-13.0 years) was 9.7 years shorter than men without these risk factors (HLE: 22.6 years, 95% CIs: 22.4-22.8 years). Similarly, HLE at age 65 in women with grade II/III hypertension, obesity, current smoker status, and DM (HLE: 16.2 years, 95% CIs: 15.9-16.5 years) was 10.1 years shorter than women without these risk factors (HLE: 26.3 years, 95% CIs: 26.3-26.3 years).

Conclusion: The large discrepancies in HLEs underscore the impact of non-communicable disease risk factors, which should be considered when formulating health interventions to improve HLE in Japanese older adults.