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.

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

Methods. We analysed 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 JAMA, BMJ, 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 behaviours. 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).

Conclusions. For the first time we quantified the volume of medical research focused on preventable behavioural 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: 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 the smaller sample size.

Conclusion: 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: 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 years 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 until 2010. HLE at age 65 years in men with grade II/III hypertension, obesity, current smoker status, and DM (HLE 12.9; 95% CI, 12.9–13.0 years) was 9.7 years shorter than men without these risk factors (HLE 22.6; 95% CI, 22.4–22.8 years). Similarly, HLE at age 65 years in women with grade II/III hypertension, obesity, current smoker status, and DM (HLE 16.2; 95% CI, 15.9–16.5 years) was 10.1 years shorter than women without these risk factors (HLE 26.3; 95% CI, 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.

The Iodine Status in Pregnancy and Offspring Health Cohort (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 5,099 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.

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 aged over 65 years 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 ratio [HR] 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). Daily replacement of 10 minutes of ST with 10 minutes 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).

Conclusion: 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.

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

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% CI, 1.2110-1.3702) during the study period. In the breakdown of the medical costs, the proportion of injection drug fees increased most rapidly.

Conclusions

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: 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 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.

Conclusion: 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, which was 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 years 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.

Conclusion: 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: Long-term sickness absence (LTSA) is an important public health challenge, yet limited data exist on its incidence in Japan. We aimed to describe the incidence of all-cause and cause-specific LTSA by sex and age, using 10-year data from a large Japanese working population, focusing on sex differences.

Methods: The study participants were employees from 16 worksites in the Japan Epidemiology Collaboration on Occupational Health Study between April 2012 and March 2022. LTSA, defined as sickness absence from work lasting 30 days or more, was recorded at each worksite. The causes of LTSA were classified using the International Classification of Diseases, 10th Revision. Incidence rates for all-cause and cause-specific LTSA were calculated based on sex and age.

Results: During 730,391 and 161,513 person-years of follow-up, 6,518 and 1,866 spells of LTSA were recorded in males and females, respectively. Females had higher incidence rates of all-cause LTSA than males (115.5 vs. 89.2 per 10,000 person-years), especially among females in their 20s and 30s. This was partly attributed to younger females experiencing higher LTSA incidence rates due to mental disorders, neoplasms, and pregnancy-related illnesses. In older age, females had higher LTSA incidence rates than males for musculoskeletal diseases and injuries/external causes, whereas LTSA incidence rates due to circulatory diseases were lower than those in males.

Conclusion: The incidence of total and cause-specific LTSA varied greatly by sex and age, highlighting the need to consider employees’ characteristics in the prevention and management of LTSA.

Background: Socioeconomic inequalities in cancer screening participation remain a public health issue worldwide. We assessed trends in cancer screening participation according to socioeconomic status in Japan between 2013 and 2022, considering the potential impact of the coronavirus disease 2019 (COVID-19) pandemic.

Methods: Data from the nationally representative Comprehensive Survey of Living Conditions (2013–2022: approximately 500,000 persons per survey) were analyzed for age-standardized self-reported cancer screening rates for stomach, lung, colon, breast (aged 40–69 years), and cervical (aged 20–69 years) cancers, stratified by education levels. An age-adjusted Poisson model was used to assess the statistical significance of changes between the survey years.

Results: A clear socioeconomic gradient was observed, particularly in stomach cancer screening, where the 2022 rates ranged from 28.3% (low education) to 58.2% (high education) for men and 20.2% to 43.2% for women, depending on education level. Between 2019 and 2022, screening rates for stomach, lung, and colorectal cancers changed by -1.2%, -0.9%, and +0.6% for men and -1.0%, +0.1%, and +1.4% for women, respectively. Breast and cervical cancer screening rates declined by 0.5% and 0.4%, respectively. The COVID-19 pandemic worsened inequalities, with a 3.1% decline in breast cancer screening among individuals with low education level, compared to a 1.0% decline among those with higher education level.

Conclusions: The COVID-19 pandemic had a minor impact on screening rates (counteracting increasing trends of screening rates), except for colorectal cancer screening rates; however, the impact was relatively severe for individuals with lower socioeconomic status, especially for women.

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 of atomic bomb survivors cohort 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% CI, 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. Nine-year interval mail questionnaires 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 the 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]), after adjusting for demographic, socioeconomic, and environmental factors.

Conclusions

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: Studies on the association between multimorbidity and mortality in large populations have mainly been conducted in European and North American populations. This study aimed to identify the association between cardiometabolic multimorbidity and all-cause and cardiovascular disease (CVD) mortality in the Asia Cohort Consortium.

Methods: In this prospective cohort study, pooled analysis was performed to evaluate the association between cardiometabolic diseases (hypertension, diabetes, ischemic heart disease, and stroke), multimorbidity, and all-cause and CVD mortality, including premature mortality, among participants from 11 Asian cohort studies. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox hazard regression.

Results: A total of 483,532 participants were followed for a median of 14.3 years. Compared with participants without any disease, those with stroke and diabetes had higher age- and sex-adjusted HRs for all-cause mortality (HR 3.9; 95% CI, 3.28–4.56). Moreover, the age- and sex-adjusted HRs for CVD mortality were highest in participants with stroke, ischemic heart disease, and diabetes (HR 10.6; 95% CI, 6.16–18.25). These patterns remained consistent after additional adjustments for smoking status and body mass index. The risk of premature mortality followed similar trends but was more pronounced.

Conclusion: These findings highlight the differential impacts of individual cardiometabolic diseases and their combinations on mortality risks. Stroke and diabetes were associated with the highest risks for all-cause and cardiovascular mortality, underscoring the need for targeted prevention and personalized management strategies tailored to these high-risk conditions in Asian populations.

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 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: 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.