Journal of Epidemiology最新文献

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Background: Pre-pregnancy underweight (BMI<18.5 kg/m²) is notably prevalent among reproductive-aged Japanese women, affecting approximately 20%, compared to less than 10% in Western countries. However, its overall impact on maternal and infant outcomes in Japanese populations has not been systematically evaluated.

Methods: We conducted a systematic review and meta-analysis following PRISMA 2020 guidelines. MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Library, and Ichushi were searched from inception to February 2024. Cohort and case-control studies examining associations between pre-pregnancy underweight and perinatal outcomes in Japanese women with singleton pregnancies were included. Primary outcomes were low birth weight (LBW), small for gestational age (SGA), and preterm birth (PTB). Random-effects models calculated pooled odds ratios (ORs) with 95% confidence intervals (CIs).

Results: Thirty-four studies were analyzed. Pre-pregnancy underweight significantly increased risks of LBW (OR=1.61, 95% CI: 1.38-1.86), SGA (OR=1.59, 95% CI: 1.55-1.63), and PTB (OR=1.23, 95% CI: 1.19-1.26). Mean birth weight was 115.02g lower (95% CI: -128.05 to -101.99) in underweight mothers.

Conclusions: Pre-pregnancy underweight among Japanese women is significantly associated with increased risks of adverse perinatal outcomes. Notably, these elevated risks persist despite the high background prevalence of underweight, suggesting that their adverse effects are not diminished in populations where it is more common. These findings underscore the importance of increasing awareness of preconception care and emphasize the need to optimize pre-pregnancy weight.

Background: Herpes simplex virus encephalitis(HSE) is a rare but life-threatening condition. While the disease has been well characterized in Western countries, large-scale epidemiological data from Japan are lacking.

Methods: Using the Diagnosis Procedure Combination(DPC) Study Group database, we identified patients hospitalized with HSE between July 2010 and March 2023. Patients were identified using ICD-10 codes. Nationwide incidence was estimated by multiplying the observed case counts by the annual ratio of total discharges in the national MHLW-DPC database to those in the DPC Study Group. We used generalized estimating equations (GEE) to account for clustering within hospitals in multivariable models. In-hospital mortality and functional and neurological outcomes were assessed. Multivariable logistic regression identified prognostic factors.

Results: A total of 6,788 patients were identified. The annual incidence of HSE ranged from 5.7 to 8.2 per 100,000 hospitalizations. Overall, in-hospital mortality was 6.0%. Of 6,378 survivors, 2,295 (36.0%) had a Barthel Index score ≤90 and 1,602 (25.1%) had impaired consciousness (Japan Coma Scale ≥1) at discharge. A composite poor outcome (death or impaired consciousness) occurred in 2,012 (29.6%). Older age (especially ≥80 years), impaired consciousness at presentation, and comorbidities such as congestive heart failure, chronic renal disease, malignancy, and underweight status were associated with in-hospital mortality and poor outcomes.

Conclusion: This multicenter analysis of HSV encephalitis in Japan showed that HSV encephalitis in Japan was associated with substantial disability among survivors, in addition to non-negligible mortality. Our findings highlight the need for post-acute rehabilitation to reduce the burden of residual disability.

Background: The impact of the coronavirus disease 2019 (COVID-19) pandemic on changes in physical activity, particularly diurnal patterns, remains unclear. We investigated temporal changes in daily steps before and after the emergency declaration in Japan during the COVID-19 pandemic.

Methods: Nationwide de-identified data from users of a physical activity-promoting smartphone application were collected. Daily and hourly steps were measured using smartphones from January 2019 to September 2020. Linear mixed models estimated changes in steps before, during, and after the April and May 2020 emergency declaration relative to 2019, involving 3,480 users (daily steps) and 3,402 users (hourly steps).

Results: Compared to the 2019 baseline, daily steps decreased during the emergency declaration (April: -1115 steps/day [95% confidence interval, -1233 to -998]) and only partly recovered thereafter (July: -496 steps/day [-609, -382]). This decline was greater among participants aged 18-39 (P for interaction < 0.05). By time of day, steps significantly decreased during weekday morning commutes and at night (e.g., 21:00: -136 steps/hour [-153, -119]) and during weekend days and late evenings (e.g., 12:00: -173 steps/hour [-196, -151]). After the declaration was lifted, step counts recovered but were still lower at night (e.g., 21:00 on weekends: -120 steps/hour [-135, -106]).

Conclusions: Daily steps decreased after the emergency COVID-19 declaration in Japan. Even after the emergency period ended, there was a persistent population-level decline in daily steps, with a partial shift in the diurnal pattern. Efforts are needed not only to restore but also to further promote physical activity beyond pre-pandemic levels.

Background: In April 2016, Japan mandated higher-level hospitals (i.e., Special Functioning Hospitals [SFHs] and Regional Medical Care Support Hospitals [RMCSHs] with ≥ 500 beds) to charge additional fees for non-referral first visits to facilitate hospital function differentiation. The mandate expanded to RMCSHs with 400-499 beds and 200-399 beds in April 2018 and April 2020, respectively. We investigated changes in referral rates (proportion of referred to first-visit patients) before and after the fee's implementation.

Methods: Using a community-based insurance claims database from a single prefecture in Japan, we extracted claims for first visits to hospitals with ≥ 200 beds between April 2014 and March 2022 and calculated monthly referral rates to five hospital groups (SFHs, RMCSHs with ≥ 500, 400-499, and 200-399 beds, and non-designated hospitals with ≥ 200 beds). We conducted a controlled interrupted time-series analysis by hospital category, treating non-designated hospitals as controls.

Results: Of 405,087 first-visit patients (mean age 54.9 years [standard deviation 20.2]; 53.2% female), 157,734 (38.9%) had a referral. The average referral rate to SFHs was high pre-mandate and did not increase. With the mandate, referral rates to RMSCHs with ≥ 500 beds and 400-499 beds rose by 5.10% (95% confidence interval: 1.84-8.35) in 2016 and 4.49% (0.28-8.70) in 2018, respectively, and stabilized afterward. Referral rates to RMCSHs with 200-399 beds remained unchanged.

Conclusions: Average referral rates increased when the additional fee was mandated for RMCSHs with ≥ 400 beds, although the influence on health outcomes remains unclear.