Background: Our previous observational cohort study, the Kashima Scan Study (KSS), identified associations between lifestyle, cerebral small vessel disease (SVD) as detected by magnetic resonance imaging of the brain, and disease outcomes including cognitive impairment and vascular diseases. However, established modifiers of the outcomes such as genetic background, drinking and exercise habits, and socioeconomic status were not considered. Regarding genetic factors in particular, the ALDH2 rs671 variant, East Asian-specific diversity, and APOE status are expected to have strong effects. The aim of KSS-2 is to examine the interactions of genetic background, lifestyle factors including drinking habit, socioeconomic status, and/or SVD markers for cognitive impairment, vascular disease, and death.

Method: The KSS-2 is a prospective regional observational study of a healthy Japanese cohort that will clarify lifestyle habits to better maintain brain health from midlife by genotype. Japanese adults who underwent brain health checkups at their own expense are enrolled and will be followed-up for 10 years. We will extend the protocol of the KSS to include genetic background and potential confounding factors, including lifestyle (including drinking and exercise habit) and socioeconomic status, and perform survival analyses. The study outcomes are cognitive impairment, vascular events, and death.

Results: We enrolled 908 healthy adults (mean age 64.2 years; range 35 to 84 years; 41% male) from September 1, 2018 until December 31, 2024.

Conclusion: This study will provide important insights into the development of individualized health intervention strategies.

Background: The efficacy of routine childhood immunization depends on timely vaccine uptake and facility use patterns. This study examined the association between pediatric vaccination facility use patterns and routine childhood immunization uptake among children up to age eight years.

Methods: As part of the Kochi Adjunct Study of the Japan Environment and Children’s Study (JECS), we analyzed data from 1,644 participants whose Maternal and Child Health Handbook photographs were collected in the eighth year of the cohort study. Maternal and Child Health Handbook records determined immunization completion. Participants were categorized into four groups based on pediatric vaccination facility use patterns: single facility use throughout, multiple facility use during the first period, multiple facility use during the second period, and multiple facility use throughout both periods. Maternal and child characteristics were collected via paper-based questionnaires. Associations between facility use patterns, sociodemographic factors, and immunization completion were analyzed using chi-square tests and logistic regression.

Results: Overall, routine childhood immunization completion was observed in 1,259 (76.6%) participants. Chi-square tests indicated that marital status, educational level, lower parity, never smoking, not attending nursery, and breastfeeding practice for infants aged four months old were significantly associated with routine childhood immunization completion. Single facility use throughout the immunization period was observed in 1,011 (61.5%) participants. Multiple facility use (38.5%) was associated with higher odds of routine childhood immunization incompletion than single facility use. This association was the strongest for those who used multiple facilities throughout the vaccination period (adjusted odds ratio, 1.90; 95% confidence interval, 1.24–2.91).

Conclusions: Single pediatric facility use was associated with higher routine immunization uptake. Our findings suggest that encouraging the use of one medical institution for a child’s vaccinations may be a useful approach to consider when addressing vaccination coverage challenges.

Background: The objective of this study was to investigate the potential link between myopia in adolescents and exposure to per- and polyfluoroalkyl substances (PFASs).

Methods: This investigation included 1971 subjects with accessible PFAS level data, myopia status, and associated variables from four cycles of the National Health and Nutritional Examination Survey (NHANES). The investigation focused on specific PFAS compounds found in the serum, including perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS), chosen for their frequent detection. Owing to the skewed nature of the PFAS level data, the PFAS levels were log-transformed (Ln-PFAS) prior to analysis. Logistic regression, restricted cubic spline modeling, subgroup analysis, and sensitivity analysis were used to examine the associations between exposure to PFASs and the onset of myopia.

Results: PFOA levels were significantly associated with myopia risk (OR: 1.33; 95% CI: 1.05–1.69; P = 0.019). More specifically, with respect to the first quartile, the second quartile (OR_Q2: 1.69; 95% CI: 1.16–2.46; P = 0.007), third quartile (OR_Q3: 1.45; 95% CI: 1.03–2.03; P = 0.035), and highest quartile (OR_Q4: 1.58; 95% CI: 1.12–2.21; P = 0.010) of participants presented with increased myopia risk. Mediation analysis revealed that PFOA and myopia risk were partially mediated by serum albumin (ALB), with a mediation percentage of 22.48% (P = 0.008). A nonlinear inverted U-shaped relationship was identified between the level of PFOA and myopia risk (P for nonlinearity = 0.005).

Conclusion: Our findings suggest a potential link between exposure to PFOA and the likelihood of myopia development in young individuals and a mediating effect of serum ALB on this relationship. Notably, PFOA was identified as a key PFAS significantly contributing to the observed link between PFAS exposure and myopia risk. The potential threat of PFOA to myopia should be examined further.

Background: The demand for aged-care services in Japan has surged due to the country’s aging population. Furthermore, nationwide survey on the current state of aged-care services revealed that the primary reason for the resignation of women working in these sectors was poor interpersonal relationships. Moreover, given that women working in aged-care services work in shifts around the clock to manage the health and safety of the people in their care, they are at high risk of health-related issues including insomnia symptoms. Thus, we aim to examine the association between levels of satisfaction with interpersonal relationships (LSIR) and insomnia symptoms for women working in aged-care services in Japan, as well as the effect of work–life imbalance on the association between LSIR and insomnia symptoms.

Methods: In this cross-sectional study, the participants were 472 women aged 18–60 years who worked in aged-care services in Japan in 2014–2016. Insomnia symptoms were measured using the Athens Insomnia Scale, and scores of 6 or greater indicated the presence of insomnia. LSIR were assessed through self-administered questionnaires and evaluated at three levels. The association between LSIR and insomnia symptoms was evaluated using a multinominal logistic regression model. Path analysis was used to examine the potential effects of LSIR on insomnia symptoms by incorporating covariates such as work–family conflict, marital status, and depressive symptoms.

Results: Compared to high LSIR, the multivariable-adjusted odds ratios (95% confidence interval) of insomnia symptoms were respectively 1.36 (0.81–2.30) and 2.42 (1.11–5.23) for medium and low LSIR. The path analysis showed that low LSIR were significantly associated with having high work-to-family (W-to-F) conflict and being single.

Conclusions: Low LSIR were significantly associated with insomnia symptoms among women working in aged-care services in Japan. High W-to-F conflict exacerbated this relationship. Therefore, enhancing interpersonal relationships may be necessary for preventing insomnia. However, due to the cross-sectional nature of our study, causality cannot be inferred. Further longitudinal research is needed to better understand these associations.

Background: Cardiovascular disease (CVD) is the predominant cause of mortality in China. However, the mechanisms linking sarcopenia to CVD remain poorly understood, particularly in normal-weight populations. Individuals with the absence of overweight or obesity may tend to experience missed opportunities for timely intervention. This study aimed to investigate the longitudinal association between sarcopenia and incidence of new-onset CVD in a normal-weight population, and to examine the mediating effect of functional limitation in this relationship.

Methods: We conducted a closed-cohort analysis using a nationwide sample of 4,147 middle-aged and older adults with normal weight in China. We performed Cox proportional hazards regression analysis to explore the associations of baseline sarcopenia with incident CVD. The difference method was applied to estimate the mediation proportion of functional limitation in this association.

Results: Over a mean follow-up period of 7.62 years, CVD occurred in 835 participants. In the multivariable-adjusted Cox model, individuals with sarcopenia exhibited a significantly higher likelihood of developing incident CVD compared to those without sarcopenia (adjusted hazard ratio [aHR] = 1.45, 95% confidence interval [CI]: 1.21–1.73, P < 0.001). Similar associations were observed for the incidence of heart disease and stroke. Functional limitation accounted for approximately 15.0% of the total effect of sarcopenia on incident CVD (P < 0.001).

Conclusions: Sarcopenia exerts both direct and indirect effects on incident CVD among middle-aged and older adults who are normal weight, with functional limitation serving as a significant mediator. Interventions targeting both sarcopenia and functional limitation may offer a promising strategy for enhancing cardiovascular health in this population.