BACKGROUND:Solitary death (kodokushi) has emerged as a public health and social issue in Japan with rapid population aging. However, recent epidemiological data on solitary deaths remain limited. METHODS:We conducted a population-based descriptive epidemiological study using records from the Tokyo Medical Examiner's Office from 2016 to 2023. All cases that met the study definition were selected from 110,024 records and included in the analysis. Data on demographic characteristics, postmortem interval (PMI), manner and cause of death, and underlying diseases were analyzed. RESULTS:Among 46,313 solitary death cases, 32,345 were male (69.8%, median age 70 years) and 13,968 were female (30.2%, median age 80 years). Crude mortality rates per 100,000 persons increased from 69.3 to 102.5 in males and 29.7 to 41.4 in females between 2016 and 2023. Solitary deaths exhibited seasonal variation, with peaks in summer and winter. Most cases involved pensioners and welfare recipients. PMI was longer in males than females (5 days vs. 3 days). Cardiovascular diseases were the leading cause of death for both sexes. Heat stroke predominated in summer, whereas natural deaths were more frequent in winter. More than half of cases had underlying diseases, most commonly hypertension. CONCLUSIONS:Solitary death in Tokyo's 23 wards increased over the study period. Seasonal, demographic, and clinical patterns highlight the need for season-specific prevention strategies and the potential role of primary care in mitigating risk.
BackgroundDepression has been associated with various chronic conditions, including metabolic syndrome (MetS), but findings from Japanese studies have been inconsistent and are limited to cross-sectional design. We therefore examined the longitudinal association between depressive symptoms and incidence of MetS and its components in middle-aged Japanese workers.MethodsData were analysed from 2969 public servants (aged 35-65, 73.1% male) in the Aichi Workers' Cohort Study who were free of MetS at baseline (2013), with at least one follow-up assessment (between 2014 and 2018). Depressive symptoms were assessed at baseline using the 11-item Centre for Epidemiological Studies Depression scale (CES-D-11) and categorized into tertiles: first tertile (0-4), second tertile (5-7), and third tertile (≥8). MetS was defined by the harmonized criteria for Japanese, based on waist circumference (≥90 cm for men and ≥80 cm for women), triglycerides, HDL cholesterol, blood pressure, and blood glucose levels. Multivariable logistic regression estimated ORs and 95% CIs. Restricted cubic splines and piecewise logistic regression evaluated non-linearity and a threshold.ResultsDuring five years, 391 participants (13.2%) developed MetS, with a cumulative incidence rate of 10.2% in the first tertile, 15.8% in the second tertile, and 14.9% in the third tertile. In the fully adjusted model, participants in the second and third tertile had higher odds of incident MetS (OR: 1.89, 95% CI, 1.44-2.48; OR: 1.92, 95% CI, 1.40-2.64, respectively) and high triglycerides (OR: 1.43, 95% CI, 1.08-1.90; OR: 1.80, 95% CI, 1.31-2.48, respectively) compared with those in the first tertile. Restricted cubic spline suggested non-linearity (p < 0.001) with a threshold at CES-D-11 approximately 10. Below this threshold, each 1-SD increase in CES-D-11 was associated with higher odds of incident MetS (OR 1.59, 95% CI, 1.31-1.92).ConclusionDepressive symptoms were associated with incident MetS among middle-aged Japanese workers, particularly with high triglyceride component. The association appeared non-linear, with risk increasing up to a CES-D-11 score of approximately 10 and then plateauing. This potential threshold may help improve understanding of the relationship between depressive symptoms and MetS risk, although further studies are needed before it can be used for risk stratification and prevention efforts.
BACKGROUND:This study aimed to develop a machine learning (ML)-derived nutrient risk score (NRS) and examine the association of genetic susceptibility and dietary intake with colorectal cancer (CRC) risk in Korean adults. METHODS:This hospital-based case-control study included 1,420 cases and 2,840 controls. Polygenic risk scores (PRS) were used to examine genetic susceptibility. The NRS was developed by combining five algorithms, nested cross-validation (CV), and recursive feature elimination with CV. Model performance was primarily assessed using AUC. Logistic regression was used to derive the NRS and assess the association of PRS, NRS, and their combined effect on CRC risk. RESULTS:A total of 15 nutrients were retained to construct the NRS. In mutually adjusted analyses, both scores remained independently associated with CRC risk (IV-weighted PRS: OR = 1.50; 95% CI, 1.10-2.06; NRS: OR = 3.67; 95% CI, 2.64-5.15 for the highest versus lowest tertile). NRS showed robust discriminative performance (AUC = 0.852; 95% CI, 0.833-0.872). While no significant PRS-NRS interaction was observed, the model integrating both scores significantly enhanced individual-level risk reclassification (IDI = 0.005, Continuous NRI = 0.120, P<0.005). CONCLUSION:Both PRS and NRS showed independent associations with CRC risk, and their integration significantly improved risk reclassification. NRS may serve as a useful composite metabolic marker for CRC risk stratification. Future studies incorporating longitudinal designs, larger sample sizes, and multi-omic data are warranted to further elucidate CRC risk determinants and to inform personalized risk assessment strategies.
Noise-induced hearing loss (NIHL) is the second most prevalent occupational disease in China. Due to its insidious onset, patients are often diagnosed at an irreversible stage, yet high-quality prospective cohorts addressing this critical issue remain limited. We established a multicenter prospective cohort-the Study of Health Effects from Noise Generated in China (SHENG)-with the primary objectives of systematically characterizing the epidemiological features, identifying environmental and genetic risk factors, elucidating molecular mechanisms, and investigating systemic health effects of NIHL, ultimately providing a scientific foundation for evidence-based prevention and control strategies. The baseline survey of SHENG was completed in 2023, covering eight enterprises across seven provinces and enrolling 4,660 young male workers (mean age 23.5 years). Based on high-frequency pure-tone average (3-8 kHz), 27.4% of participants were classified as having hearing loss, though most of them did not report subjective hearing difficulties. Compared with the normal hearing group, the hearing loss group had significantly more noise exposure events, higher exposure rates to occupational co-hazards such as dust and vibration, and poorer hearing protection practices. SHENG is planned to conduct follow-up assessments every 1-2 years. Through longitudinal follow-up and multidimensional data integration, this cohort will establish an "environmental-clinical-genetic" risk assessment model, elucidate the dynamic progression of NIHL and its associations with systemic diseases, and provide key evidence for refining occupational noise exposure standards and developing precision prevention strategies tailored to susceptible populations.
BackgroundPrevious studies on foreign body airway obstruction (FBAO) have primarily focused on patients who received prehospital or emergency department care. The epidemiological features of FBAO in the broader population, including cases managed outside emergency departments, remain unknown. We aimed to determine the incidence and characteristics of clinically managed FBAO using Japanese medical claims data.MethodsThis retrospective observational study was conducted using claims data from public health insurance enrollees across 16 municipalities. FBAO cases were identified from April 2020 to March 2024. The age-stratified and age-adjusted incidence rates of FBAO were calculated using the number of publicly insured individuals in the participating municipalities as the denominator.ResultsDuring the four-year observation period, a total of 1,123 FBAO cases (median age: 84 years) were identified. There were 518 (46.1%) cases in cardiac arrest on arrival and 516 (45.9%) deaths in the same month as the FBAO event. Age-stratified analyses showed that FBAO incidence rates steadily increased with advancing age, with individuals aged ≥95 years exhibiting an approximately 17-fold higher incidence than those aged 65-69 years. The age-adjusted incidence rate was 6.68 per 100,000 person-years.ConclusionThis large-scale claims-based observational study indicated that the risk of FBAO occurrence is disproportionately high among individuals of advanced age, underscoring the need for FBAO prevention and management strategies targeting highly aged populations.
BACKGROUND:Socioeconomic disparities influence diet quality, but it remains unclear how income-related differences in nutritional adequacy vary by household composition, particularly the presence of children. We examined income-related differences in nutritional adequacy among Japanese adults. METHODS:We analyzed data from 7,265 adults aged 20-79 years from the 2014 and 2018 National Health and Nutrition Surveys. Nutritional adequacy was assessed using a composite score based on dietary reference intakes. Household income was categorized as <2 million JPY, 2-<6 million JPY, or ≥6 million JPY. Linear mixed-effects models were used to estimate sex-specific associations, adjusting for sociodemographic, lifestyle, and health factors. RESULTS:Lower income was associated with lower nutritional adequacy (p for trend < 0.001), and these associations persisted after adjustment. Income-related gradients were observed in both households with and without children and were steeper among households with children, with the lowest nutritional adequacy scores observed among low-income households with children. In contrast, patterns were less apparent among older women and individuals living alone. CONCLUSIONS:Income-related differences in nutritional adequacy were observed across Japanese adults and varied according to household composition. These findings suggest that household context, particularly the presence of children, may modify income-related patterns in dietary quality.
BACKGROUND:The effects of hypnotics use on the risk of adverse pregnancy outcomes across pregnancy trimesters are underexplored. METHODS:From the data of the Japan Environment and Children's Study (JECS), we constructed cohorts of women registered between January 2011 and March 2014 who delivered a liveborn singleton child. Exposure to hypnotics during the first (Period 1) and second/third (Period 2) trimesters was assessed in interviews. We identified the outcomes, preterm birth, low birth weight, and major congenital malformations, based on medical record transcripts. For each exposure period and pregnancy outcome, we estimated the risk differences (RDs) and risk ratios (RRs) using modified least-squares and modified Poisson models, respectively, adjusting for the mother's age, body mass index, lifestyle factors, comorbidities, and other medication use. RESULTS:A total of 91,370 and 80,089 women were included for Periods 1 and 2, respectively. For Period 2, an increased risk of preterm birth (RD: 0.0748, 95% confidence interval [CI] 0.0175-0.132; RR 2.57 95%CI 1.42-4.65) and low birth weight (RD 0.0661 95%CI 0.00204-0.130; RR 1.77 95%CI 1.10-2.85) were observed among exposed compared with unexposed individuals. These risks were not observed for Period 1. The risk of major congenital malformations was not increased for both Periods 1 and 2. CONCLUSION:Hypnotic medication in late-stage pregnancy may increase the risks of preterm birth and low birth weight, although caution is warranted because of possible confounding by indication. The elevation of the risk of the usage of hypnotics at any stage of pregnancy on major malformations was not observed.
BACKGROUND:Global urbanization intensifies human contact with pet birds, increasing the risk of psittacosis. Using Shenzhen, China, as a case study, this research investigates knowledge and practices related to psittacosis prevention among professionals and pet bird owners, aiming to inform targeted urban zoonotic disease control strategies. METHODS:A cross-sectional survey was conducted from September 2023 to October 2024 in Shenzhen using a self-administered questionnaire. Participants included practitioners in bird/pigeon businesses and household bird keepers. Primary outcomes were knowledge and behavior scores. RESULTS:Among 429 participants, the median total knowledge and practice score was 47.0 (out of 80), with only 13.5% scoring above 60. Practitioners scored significantly higher than pet owners (P < 0.05). Among keepers, the lowest awareness rates were for sources of infection, clinical symptoms, and incubation period (13.2%-22.1%), and the lowest behavior formation rates were for using protective measures, waste disposal, and responding to abnormal symptoms in pigeon and bird (10.9%-15.5%). Multivariate analysis identified key factors influencing scores: among practitioners, being male, having less experience, and lacking health education were associated with lower scores (P < 0.05). Among keepers, being female, higher education, purchasing from breeding bases, keeping multiple species, and prior psittacosis diagnosis predicted higher scores, while older age (> 50) and online bird purchases predicted lower scores (P < 0.05). CONCLUSION:The overall psittacosis prevention capacity among bird-keeping populations in Shenzhen is moderate. There is an urgent need for stratified, context-specific interventions including standardized guidance and systematic health education to improve prevention effectiveness in urban settings.
BackgroundInfluenza vaccination may reduce the risk of infection-triggered ischemic stroke (IS), but evidence remains limited, particularly in Japan.MethodsThis nested case-control study examined the association between influenza vaccination and the occurrence of IS among persons aged ≥65 years in a Japanese municipality between October 2016 and September 2023. IS cases were identified from insurance claims and matched with controls based on sex, age, and month of IS occurrence. Conditional logistic regression was used to estimate the association between vaccination and IS occurrence while adjusting for covariates such as comorbidities and prescription drugs.ResultsA total of 21,476 IS cases and 107,360 matched controls were analyzed. Influenza vaccination was significantly associated with a lower odds of IS (reference: unvaccinated) when administered 0-14 days (odds ratio: 0.74, 95% confidence interval: 0.62-0.88), 15-30 days (0.51, 0.43-0.59), 31-60 days (0.50, 0.45-0.56), 61-90 days (0.79, 0.72-0.87), and 91-120 days (0.81, 0.73-0.89) before IS occurrence. In a subgroup analysis, this association was observed only during the pre-epidemic and epidemic phases. Sex- and age-stratified analyses revealed similar patterns, with some variation in the magnitude of association.ConclusionsThese findings suggest a possible short-term inverse association between influenza vaccination and IS risk in older adults, but the influence of residual confounding cannot be excluded. Further research is needed to confirm these findings and clarify the potential role of influenza vaccination in reducing IS risk.
In epidemiological research, time-to-event outcomes, commonly referred to as survival outcomes, are a common subject of investigation. Here, we first describe the circumstances under which methods of survival analysis are necessary, review the roles of hazard functions, and discuss the limitations of hazard ratios for causal inference. Second, we explain how confounding and dependent censoring, which are common in observational studies, can be addressed by inverse probability weighting and parametric g-formula estimators. We emphasize that hazards serve as building blocks for estimating counterfactual risks. Third, we summarize recent developments in defining causal estimands in the presence of competing risks, including risk without eliminating competing events, net risk, and cumulative incidence under modified treatment. To illustrate how these challenges are addressed in practice, we revisit a recent clinical study on pharmacological interventions for the onset of dementia. We further empirically compare various estimands in the presence of competing events, including separable effects, through simulations. Our overall aim is to elucidate the need to move beyond routinely used methods of survival analysis, particularly the mere estimation of hazard ratios, if the goal is to draw causal inferences. This paper provides an overview of causal survival analysis, focusing on how confounding, dependent censoring, and competing risks can be addressed to estimate causal parameters of interest (counterfactual survival functions or counterfactual risks), which are interpretable and often meaningful for investigators.
OBJECTIVES:The rising prevalence and earlier onset of hair loss have highlighted its associations with cardiovascular risk factors (hypertension, diabetes, dyslipidemia) and comorbidities among adults. This cross-sectional study examined the associations of hair loss severity with hypertension, diabetes, dyslipidemia, and cardiometabolic multimorbidity (CMM). METHODS:Hair loss was assessed via Modified Hamilton-Norwood (males) and Savin (females) scales in the Tianning cohort (N=5020). Hypertension, diabetes, and dyslipidemia were diagnosed per Chinese guidelines, with two or more coexisting conditions defining CMM. Multivariate logistic regression analyzed associations between hair loss and these diseases, including CMM. RESULTS:Compared with participants without hair loss, those with mild and severe hair loss had 29% (OR=1.29, 95% CI, 1.08-1.54) and 48% (OR=1.48, 95% CI, 1.16-1.89) higher odds of hypertension, respectively. Severe hair loss was also associated with 44% higher odds of diabetes (OR=1.44, 95% CI, 1.11-1.86) and 30% higher odds of CMM (OR=1.30, 95% CI, 1.02-1.65). No significant association was observed for dyslipidemia after multivariable adjustment. CONCLUSION:Greater hair loss severity was associated with higher odds of hypertension, diabetes, and CMM in this cross-sectional analysis. These findings suggest that hair loss severity may be relevant to cardiometabolic health in adults.
BACKGROUND:Individuals receiving public assistance have been reported to be at increased suicide risk; however, evidence from emergency medical settings remains limited. This study investigated the population-level association between public assistance status and suicide-related cardiac arrest using events captured through emergency department presentations. METHODS:We conducted a nationwide registry-based study using the Japan Registry of Self-harm and Suicide Attempts, including patients presenting to emergency and critical care centers following self-harm or suicide attempts from December 2022 to December 2023. The primary outcome was suicide-related cardiac arrest, and non-fatal self-harm was examined as a related outcome. Adjusted incidence rate ratios (aIRRs) were estimated using Poisson regression models with the log of the population at risk included as an offset, adjusting for age and sex. National suicide statistics were analyzed for validation. RESULTS:Among 1,757 patients, 207 (11.8%) were receiving public assistance. Public assistance status was associated with a higher incidence of suicide-related cardiac arrest compared with non-recipients (aIRR 3.34, 95% confidence interval [CI], 1.60-6.95). A strong association was also observed with non-fatal self-harm (aIRR 13.10, 95% CI, 8.25-20.80). Similar associations were observed across sex and age groups. Analyses using national suicide statistics confirmed a consistent association (aIRR 2.21, 95% CI, 1.50-3.26). CONCLUSIONS:In this nationwide registry-based study using events captured through emergency department presentations, public assistance status was associated with suicide-related cardiac arrest and non-fatal self-harm. At the population level, public assistance recipients showed a higher incidence of suicide-related cardiac arrest, supporting the public health relevance of this socioeconomic indicator.
BACKGROUND:Dietary diversity is associated with enhanced cognitive function and reduced dementia risk among older adults; however, its relationship with structural brain ageing remains unclear. We examined cross-sectional and longitudinal associations between dietary variety score (DVS) and brain volume among older Japanese adults. METHODS:We analysed data from the Neuron to Environmental Impact across Generations (NEIGE) cohort, a population-based longitudinal study of community-dwelling Japanese adults aged 65-84 years. The analysis included 279 participants with baseline and follow-up magnetic resonance imaging (MRI) data. Dietary diversity was assessed at baseline using the DVS based on the consumption frequency of 10 food groups. Hippocampal and total grey matter volumes were measured using MRI at baseline (2017) and follow-up (2021). Cross-sectional associations were examined using multivariable linear regression models, and longitudinal associations were assessed using linear mixed-effects models adjusting for confounders. RESULTS:Mean follow-up was 4.1-year (SD 0.2). In cross-sectional analyses, DVS was not significantly associated with brain volume. In longitudinal mixed-effects models, the interaction between baseline DVS and duration was not significantly associated with changes in total grey matter volume (-128.11 mm3/year per 1-point increase in DVS; 95% CI, -267.86 to 11.65; p = 0.07). Similarly, no significant association was observed for hippocampal volume (-0.44 mm3/year per 1-point DVS; 95%CI, -3.52 to 2.65; p=0.78). CONCLUSIONS:Dietary diversity was not significantly associated with brain volume or with the rate of change in brain volume over time among older Japanese adults.
BACKGROUND:Frailty is a growing public health concern, with emerging evidence highlighting the importance of social determinants, including external and intra-household isolation. This study examined the association between intra-household isolation and frailty among community-dwelling older adults in Japan and explored whether external social connections modified this association. METHODS:Data were obtained from the 2023 baseline survey of the Wako Cohort Study, including 6,429 participants aged ≥65 years in Wako City, Saitama Prefecture, without long-term care certification levels 3-5 (men: 45.0%; mean age: 76.5 years). Intra-household isolation was defined as living with others but having minimal interaction (talking <15 min/day and spending most time alone at home). Frailty was assessed using the 25-item Kihon Checklist. Modified Poisson regression analysis estimated the associations, adjusting for sociodemographic factors, health behaviors, health conditions, and external social connections. RESULTS:Intra-household isolation was observed in 5.3% of participants, while 21.0% lived alone. Frailty was observed in 28.3% of participants. Individuals with intra-household isolation were more likely to be frail than non-isolated individuals (prevalence ratio [95% confidence interval]: 1.42 [1.26-1.59]). This association remained significant when compared with individuals living alone (1.34 [1.16-1.54]) and was stronger among those aged 65-74 years than those aged ≥75 years. No significant interaction was observed between intra-household isolation and external social connections. CONCLUSION:Intra-household isolation among cohabiting older adults was independently associated and showed a stronger association with frailty than living alone. These findings suggest that living with others does not necessarily have protective effects unless meaningful interactions exist.
BackgroundPrevious studies have reported educational inequalities in all and site-specific cancer mortality. However, the mechanisms underlying this association remain unclear. We investigated the association between educational level and all- and site-specific cancer mortality and examined potential mediating factors.MethodsWe conducted a longitudinal study using data from the Japan Gerontological Evaluation Study (JAGES), initiated in 2010 with 7-year follow-up targeting independent adults aged ≥65 years. Self-report questionnaire data were linked to mortality records from municipal registries. Educational level was exposure (<10/10-12/>12 years for competing risk models and <10/≥10 years for causal mediation analysis). All- and site-specific cancer mortality were outcomes. Competing risk models estimated sub-distribution hazard ratios (SHRs) and 95% confidence intervals (CIs). Causal mediation analysis assessed mediating effects of smoking status, drinking status, health examination, vegetable and/or fruit intake, and walking time.ResultsAmong 43,478 participants (46.6% men, mean age 73.7 years), the 7-year mortality from all cancers was 5.1%. Low educational level was associated with higher all-cancer mortality (SHR for the lowest compared with the highest 1.27; 95%CI, 1.13-1.44). Similar associations were observed for tracheal and lung, and esophageal cancer mortality. The association between educational level and all cancer mortality was significantly mediated by smoking status (5.6%), health examination (8.0%), and walking time (7.1%), but not by drinking status and vegetable and/or fruit intake.ConclusionLower educational level was associated with a higher risk of all cancer, tracheal and lung cancer, and esophageal cancer mortality. Health behaviors partially explained these associations.
BACKGROUND:Angiopoietin-like protein 2 (ANGPTL2) is an aging-associated protein that contributes to the maintenance of tissue homeostasis. Excessive activation of ANGPTL2 disrupts this homeostatic process, leading to several adverse conditions, such as chronic inflammation, abnormal tissue remodeling, insulin resistance, and carcinogenesis. Nevertheless, only a very few studies have investigated the relationship between circulating ANGPTL2 concentrations and cause-specific mortality risk in the general population. METHODS:We conducted a prospective cohort study involving 2,912 community-dwelling Japanese adults aged ≥40 years with no prior history of cardiovascular diseases or cancer. Baseline serum ANGPTL2 concentrations (collected in 2002-2003) were quantified, and the participants were followed up for a median of 15.2 years. Hazards ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality were estimated using Cox proportional hazards models. RESULTS:During the follow-up period, 601 participants died (139 from cardiovascular diseases, 200 from cancer, 142 from infectious diseases, and 120 from other causes). Higher serum ANGPTL2 levels were significantly associated with increased risks of all-cause and cause-specific mortality (HR [95% CI] per 1-SD increment in log-transformed serum ANGPTL2 concentration: 1.34 [1.23-1.47] for all-cause mortality; 1.28 [1.06-1.55] for cardiovascular death; 1.31 [1.12-1.53] for cancer death; and 1.27 [1.05-1.54] for death from infectious diseases) after adjustment for potential confounders. These associations were modestly attenuated after additional adjustment for mediators related to insulin resistance and chronic inflammation. CONCLUSIONS:These findings indicate that elevated serum ANGPTL2 concentrations are associated with a higher risk of mortality from multiple causes.
BackgroundNorth-south differences in context and lifestyle may shape multimorbidity patterns in China. We compared multimorbidity between two northern (Liaoning, Jilin) and two southern (Guangdong, Jiangsu) CNHS provinces in eastern China using association rule mining (ARM) and sequential pattern mining (SPM).MethodsWe analyzed 19,067 adults (≥20 years) and 20 chronic conditions. ARM identified co-occurrence rules and reported support (proportion with the combination), confidence (P(consequent|antecedent)), and lift (observed/expected co-occurrence; >1 indicates positive association). SPM summarized common diagnosis-order sequences using sequence support (percentage of participants exhibiting an ordered sequence). Sensitivity analyses were restricted to self-reported physician diagnoses.ResultsMultimorbidity prevalence was 37.85% (age-standardized 32.84%), higher in northern than southern provinces (41.39% vs. 34.08%; standardized 35.41% vs. 31.04%). Hypertension, hyperuricemia, and diabetes were most common. Cardiovascular/cerebrovascular conditions were more frequent in the north, whereas anemia and kidney stones were more common in the south. ARM suggested metabolic-renal clustering in the south (e.g., CKD→gout, support=1.18%, confidence=26.14%, lift=2.60; gout+anemia→CKD, support=0.55%, confidence=38.89%, lift=3.71) and musculoskeletal-cardiovascular links in the north (e.g., osteoarthritis→spinal disease, support=0.52%, confidence=24.69%, lift=2.22; CTRD→CHD, support=0.63%, confidence=28.24%, lift=1.26). Common SPM sequences included hypertension→hyperuricemia (24.22%) and hypertension→diabetes→hyperuricemia (5.32%); hypertension→hyperuricemia→CKD was more frequent in the south (2.28%), while hypertension→CHD→hyperuricemia was more frequent in the north (5.70%). Sensitivity analyses showed broadly consistent regional contrasts.ConclusionsMultimorbidity burden and structure differed between the northern and southern provinces, supporting province-tailored prevention and integrated care.
Sleep and physical activity play a crucial role in brain and mental health. While traditional self-reported methods and research-grade accelerometers have several limitations, consumer-grade wearable devices, such as Fitbit, allow continuous, objective, and real-life data collection. The purpose of this article is to report the study protocol and participant characteristics of a wearable device survey that primarily aims to examine the relationship between brain health and long-term patterns of daily physical activity and sleep.Nearly 2,000 participants were recruited between September 2022 and December 2023, as part of the Tohoku Medical Megabank Brain Magnetic Resonance Imaging Study, to wear Fitbit Charge 5 devices for 1 year, continuously tracking physical activity and sleep. Additionally, home blood pressure measurements and questionnaire data on housing conditions, psychological distress, and medication were collected every 4 months for a total of four assessments.The mean age of the participants was 58.5 years and 37.4% were men. For the first 30 days after the recruitment, mean step count was 8,910 steps/day, and a mean total sleep time was 370.4 min/night (approximately 6.2 h). The mean morning systolic blood pressure and diastolic blood pressure were 126.2 and 75.5 mmHg, respectively.This study provides a unique opportunity to integrate longitudinal consumer-grade wearable data, brain MRI, multiomics data, and comprehensive health records from existing cohorts to advance precision medicine and help prevent mental and neurodegenerative diseases, such as dementia. Limitations include potential selection bias, and a relatively smaller sample size than larger global studies.
