Environmental Health and Preventive Medicine最新文献

Background: The prevalence of constipation is increasing with the aging of the population, significantly impacting the quality of life in older adults. However, a comprehensive analysis of the physical, psychological, and social correlates of constipation in Japan remains limited. This study aimed to examine factors associated with defecation status in community-dwelling older adults in Japan.

Methods: We conducted a cross-sectional analysis of 8,009 community-dwelling residents aged 65 years and older who completed the baseline health and lifestyle questionnaire as part of the Yamagata Cohort Study. Constipation was defined as fewer than three bowel movements per week. Physical, psychological, and social factors were assessed using self-administered questionnaires. Associations with constipation were examined using chi-square tests and multivariable logistic regression, including sex-stratified models.

Results: Constipation was observed in 407 participants (5.1%). In the multivariable analysis, it was significantly associated with being female (odds ratio [OR] = 1.26, 95% confidence interval [CI]: 1.02-1.56; reference: male), having a body mass index (BMI) ≥25 kg/m² (OR = 0.74, 95% CI: 0.58-0.96: reference: <25 kg/m²), feeling unhappy (OR = 1.94, 95% CI: 1.16-3.22; reference: happy), experiencing residual stool sensation (OR = 2.77, 95% CI: 2.11-3.64; reference: no sensation), having moderate overactive bladder (OAB) symptoms (OR = 1.42, 95% CI: 1.13-1.79; reference: no OAB symptoms), and perceived living situation on current income as difficult (OR = 1.70, 95% CI: 1.36-2.12; reference: comfortable). Sex-stratified analyses revealed partially different patterns of associated factors between men and women.

Conclusion: Constipation in community-dwelling older adults in Japan was associated with multiple physical, psychological, and social factors, with sex-specific differences. Given the cross-sectional design, causality cannot be inferred. These findings suggest that constipation in older adults may be associated with a complex interplay of physical, psychological, and social factors, highlighting the need for comprehensive and integrated approaches in community settings. Integrated geriatric care that addresses these dimensions may be effective in preventing and managing constipation in this population.

Background: Japan is experiencing a rapid demographic shift toward a super-aged society, making the extension of healthy life expectancy a national priority. Oral self-care, particularly tooth brushing habits, may play a critical role in preventing functional decline among older adults, yet evidence in this population remains limited. This study aimed to examine the association between specific tooth brushing behaviors-frequency, timing (especially before bedtime), and use of interdental cleaning tools-and incident disability among community-dwelling older adults in Japan.

Methods: A three-year prospective cohort study was conducted in City A, Nara Prefecture, involving 7,785 older adults aged 65 and above who were free of disability at baseline. Tooth brushing habits were assessed via self-administered questionnaires, and incident disability was defined as new certification under Japan's Long-Term Care Insurance system. Covariates included age, gender, socio-economic status, lifestyle habits, physical and mental health, and oral health indicators. Multiple logistic regression analyses were used to estimate adjusted odds ratio (AOR) and 95% confidence interval (CI) for incident disability.

Results: During the follow-up period, 713 participants (9.2%) developed incident disability. After adjustment for covariates and mutual adjustment for other tooth brushing habits, non-daily brushing before bedtime and non-use of interdental cleaning tools were associated with higher odds of incident disability (AOR for non-daily vs daily brushing before bedtime = 1.55, 95% CI: 1.19-2.01; AOR for non-use vs use of interdental cleaning tools = 1.34, 95% CI: 1.11-1.62). These associations were particularly evident among individuals aged 75 and older.

Conclusion: Daily brushing before bedtime and the use of interdental cleaning tools were independently associated with lower odds of incident disability among community-dwelling older adults. Nevertheless, causal inference is limited, and residual confounding cannot be ruled out.

Background: Thyroid hormones support endothelial repair, whereas bedtime snacking is linked to a higher risk of chronic kidney disease (CKD). Since endothelial dysfunction is a core feature of CKD, bedtime snacking could potentially contribute to subclinical hypothyroidism (SCH) by elevating the demand for endothelial repair. This study aimed to explore the association between bedtime snacking and SCH.

Method: In this cross-sectional study, 1,478 Japanese individuals aged 40-69 years with normal thyroid function were enrolled; normal thyroid function was defined as free triiodothyronine (T3) and free thyroxine (T4) levels within the reference ranges and the absence of thyroid-related medication use. Individuals with elevated serum concentrations of TSH (>4.01 µIU/mL) were defined as having SCH. Bedtime snacking was determined in the basis of participants' affirmation to the question "Do you consume a night meal or snack after dinner, within two hours of bedtime, three or more times per week? (Yes, No)".

Results: In the study population, 263 individuals reported a bedtime snacking habit, whereas SCH was identified in 81 individuals. A statistically significant association was found between bedtime snacking and SCH. The sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (CI) were 1.77 (1.05, 2.99). This association remained significant after additional adjustment for skipping breakfast and late dinner; 1.83 (1.07, 3.11), and further adjustment for free T4, atherosclerosis, hypertension, diabetes, CKD, and thyroid cysts; 1.93 (1.11, 3.35), respectively.

Conclusion: Bedtime snacking is positively associated with SCH, potentially due to an increased physiological demand for endothelial repair. This finding is not only an efficient tool for diagnosing the early stages of endothelial and thyroid dysfunction, but also for clarifying the mechanism underlying the regulation of thyroid hormones related to endothelial health.

Background: Mass gatherings during the peak summer months pose a notable risk for heat-related illnesses due to extreme heat and humidity. We aimed to identify trends in preventive measures taken against heat-related illnesses at mass gathering rock festivals in Japan during the summer of 2023, in terms of associations with online sources regarding the event details and heat risk communication; daily maximum wet bulb globe temperature (WBGT) values; and emergency heat-related illness transport data.

Methods: Four rock festivals (festivals A-D), held in July and August 2023, were analyzed. Publicly available online sources were reviewed to examine the event details, heat risk communication, and preventive measures. Daily maximum WBGT values were obtained from the meteorological observation points closest to each festival venue. Emergency heat-related illness transport data were assessed to identify trends during the rock festivals.

Results: Three festivals (festivals A, B, and D) recorded daily maximum WBGT values at or above the "Danger" threshold (≥31 °C), while festival C reached the "Severe Warning" level (≥28 °C and <31 °C). Despite the high WBGT, no heat advisories were issued on the websites of festivals A and B. Festival C gave a basic advisory on heat precautions. Festival D implemented more comprehensive countermeasures, including public warnings and recommendations to carry hats, towels, and portable fans. Notably, emergency transport for heat-related illnesses increased in the regions hosting festivals B and D.

Conclusions: All festivals posed substantial heat-related health risks. Enhanced public risk communication and consistent preventive measures are essential for mitigating preventable incidents during mass gatherings in extreme heat.

Background: Per- and polyfluoroalkyl substances (PFAS) have raised significant health concerns. In 2019, drinking water source was changed due to PFAS contamination in the Tama region, Tokyo, Japan. This study aims to determine the PFAS exposure levels after reduction in drinking water contamination, and to estimate the half-lives of linear isomers of perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) in serum samples from residents.

Methods: 17 participants in 2020 and 2023 from Tama region, Tokyo, Japan (all females, age 53-83 years) were examined. PFAS concentrations in serum in 2023 were measured using gas chromatography-mass spectrometry. Biological half-lives were estimated using first-order kinetics model.

Results: The investigated population was exposed to six PFAS at levels associated with potential health risks, with 95% of them having total PFAS concentrations exceeding 20 ng/mL in 2023. Serum PFOS, PFHxS and PFOA levels decreased from 2000 to 2023 (p < 0.05 by paired t-test). The estimated half-lives for PFOS, PFHxS, and PFOA were 3.9 years (95% CI: 3.4-4.6), 5.7 years (95% CI: 4.6-7.5), and 8.0 years (95% CI: 6.0-10.0), respectively. After subtraction of background values in Japan, the estimated half-lives were 2.7 years (95% CI: 2.3-3.4) for PFOS, 5.6 years (95% CI: 4.5-7.4) for PFHxS, and 5.1 years (95% CI: 4.1-6.8) for PFOA.

Conclusions: This study demonstrates participants had still higher serum PFAS levels and these PFAS elimination half-lives in the investigated Japanese population are at years order.

Background: In Japan, specific health guidance is a program based on health checkups to prevent metabolic syndrome. However, dropout from the program is an issue and reduces opportunities to improve cardiovascular risk. Lack of awareness of health checkup results is thought to be associated with dropout, but the association remains unclear. This study aimed to investigate the impact of awareness of health checkup results with related attitude on dropout from specific health guidance among teachers.

Methods: Data from medical insurance providers primarily serving teachers (n = 7,031; mean age = 51.19 years old) were analysed. Participants were categorized into 3 groups based on awareness of health checkup results and attitude toward adopting healthy lifestyles at the first time of the health guidance: awareness with the attitude (level 1 group), awareness without the attitude (level 2 group), and lack of awareness (level 3 group). Dropout rates from specific health guidance and improvement in health checkup results in the following year were compared across groups.

Results: Dropout rates were 19.88% in the level 1 group, 22.03% in the level 2 group, and 27.77% in the level 3 group (P < 0.001 in a trend test). Compared with the level 1 group (reference), adjusted risk ratios for dropout were 1.139 (95% confidence interval: 1.001-1.295) for the level 2 group and 1.320 (95% confidence interval: 1.132-1.540) for the level 3 group. The degree of improvement in health checkup results decreased progressively from level 1 to level 3.

Conclusions: Among the participants who received the first health guidance, awareness of health checkup results combined with attitude to adopt healthy lifestyles was associated with lower dropout from specific health guidance and greater improvements in cardiovascular risk. Such individuals' awareness and attitudes may help predict individuals at risk of dropout from health guidance in this population.

Background: Child maltreatment, traditionally considered a maternal issue in Japan, increasingly involves fathers. Despite the rise in paternal participation, the recognition of and engagement in child maltreatment remains poorly investigated in Japan. We explored the association between parental recognition and engagement in maltreatment, stratified by parental sex.

Methods: An Internet survey was conducted in Japan from July to August 2021, involving 8,819 parents (1,671 fathers, and 7,148 mothers) with children under 24 months of age. A self-report questionnaire assessed recognition of and engagement in maltreatment behaviors, including physical and psychological maltreatment and neglect. Poisson regression analysis estimated prevalence ratios of engagement in maltreatment behaviors by recognition status, stratified by parental sex.

Results: Harsh behaviors widely recognized as maltreatment (unrecognition was less than 15% for both sexes) included beating the child (fathers: 13.5%, mothers: 6.9%), repeatedly insulting the child (fathers: 13.3%, mothers: 7.7%), and not feeding the child (fathers: 13.1%, mothers: 6.3%). Engagement in any form of maltreatment was reported by 14.2% of fathers and 9.6% of mothers in this sample. The overall prevalence of physical maltreatment was 10.5% among fathers and 5.7% among mothers. Similarly, fathers reported 6.1% overall neglect and mothers reported 1.9%. The prevalence of psychological maltreatment was 4.4% among fathers and 3.5% among mothers. For both sexes, lack of recognition of maltreatment was associated with a higher prevalence of engagement in such behaviors (fathers: adjusted prevalence ratio [aPR] 2.06, 95% confidence interval [CI] 1.43-2.99; mothers: aPR 1.88, 95% CI 1.53-2.33). This association was consistent across all subtypes, with the strongest for neglect (physical maltreatment [fathers: aPR 2.49, 95% CI 1.63-3.79; mothers: aPR 2.06, 95% CI 1.59-2.66], psychological maltreatment [fathers: aPR 2.22, 95% CI 1.30-3.78; mothers: aPR 1.43, 95% CI 1.09-1.88], and neglect [fathers: aPR 4.28, 95% CI 2.71-6.78; mothers: aPR 4.75, 95% CI 3.23-6.99]).

Conclusions: Lack of recognition was associated with greater engagement in maltreatment, particularly neglect, for both parents, based on these findings. Findings underscore the need for parenting education and support targeting both parents.

Background: Epidemiological evidence increasingly implicates ambient particulate matter (PM) as a contributor to diabetes progression and premature mortality; however, the strength and consistency of these associations remain uncertain. This systematic review and meta-analysis quantified the relationship between exposure to major PM fractions-particularly PM_2.5 and PM₁₀-and the risk of diabetes-related mortality in adult populations.

Methods: Following PRISMA and MOOSE guidelines, five databases were searched through September 30, 2025. Eligible observational studies assessed long- or short-term exposure to ambient PM and reported quantitative estimates for diabetes-associated deaths. Effect sizes were pooled using random-effects models and expressed as relative risk (RR) per 10 µg/m³ increment in PM concentration. Subgroup and meta-regression analyses explored sources of heterogeneity.

Results: Thirty-six studies (41 datasets) were included. Pooled analysis showed a significant positive association between PM_2.5 exposure and diabetes-related mortality (RR = 1.123; 95%CI: 1.099-1.147; I² = 95.3%). The effect was stronger for long-term exposure (RR = 1.296; 95%CI: 1.197-1.395) and prospective cohorts (RR = 1.327; 95%CI: 1.189-1.466). PM₁₀ was also associated with increased risk, though with smaller magnitude (RR = 1.021; 95%CI: 1.007-1.035; I² = 81.7%). Meta-regression confirmed exposure duration as a significant modifier (p = 0.014).

Conclusions: Both fine (PM_2.5) and coarse (PM₁₀) particulate matter are significantly associated with increased diabetes-related mortality, with the strongest and most consistent effects observed for chronic PM_2.5 exposure. These findings highlight the metabolic health burden of air pollution and underscore the importance of stringent air-quality standards to reduce premature diabetes deaths globally.

Background: Gut microbiota plays a crucial role not only in digestion but also in systemic physiological functions, including immune and neural regulation. High microbial diversity contributes to intestinal homeostasis, whereas reduced diversity has been associated with various diseases. Physical activity is reported to influence both the composition and function of gut microbiota; however, the impact of daily physical activity on gut microbiota in older adults remains poorly understood. This study exploratorily investigated the association between objectively measured daily physical activity and gut microbial diversity and composition in older women who are at increased risk of reduced physical activity and gut microbial dysbiosis.

Methods: A cross-sectional study assessed daily physical activity using an accelerometer-based activity monitor in 73 community-dwelling older women. We classified participants as meeting (n = 56) or not meeting (n = 17) the World Health Organization (WHO) physical activity guidelines. Fecal samples were collected and analyzed using 16S rRNA sequencing to evaluate gut microbial diversity and composition.

Results: Participants not meeting the WHO activity guidelines exhibited lower gut microbial diversity (Observed Features: 134 ± 23 vs. 161 ± 45, Chao1 index: 137 ± 24 vs. 167 ± 49, all p < 0.05) and distinct microbial community structures (weighted UniFrac distances, PERMANOVA, p < 0.05) as compared with those meeting the guidelines. In particular, the relative abundance of short-chain fatty acid-producing Ruminococcus was reduced in the less active group.

Conclusion: Habitual daily physical activity was associated with gut microbiota diversity and composition in older women in this exploratory study. In particular, the relative abundance of Ruminococcus may reflect differences in gut microbial function. Future longitudinal and interventional studies are needed to further clarify causal relationships and support the development of personalized strategies to promote gut health and healthy aging.