Journal of Epidemiology

BACKGROUND: The mechanistic associations between obesity and risk of colorectal cancer (CRC) remain unclear. Here, using body mass index (BMI) as an obesity indicator, we decomposed the total effects of obesity on the risk of CRC into: (1) direct effects, which are possibly mediated by unmeasured or currently unknown factors; (2) indirect effects mediated by circulating leptin and adiponectin; and (3) indirect effects that are not mediated by circulating leptin and adiponectin but by hyperinsulinemia and chronic inflammation (assessed via circulating connecting peptide and C-reactive protein, respectively)...

BACKGROUND: Instrumental variable (IV) methods are widely employed to estimate causal effects when concerns regarding unmeasured confounders. Although comparisons among several IV methods for binary outcomes exist, comprehensive evaluations are insufficient. Therefore, in this study, we aimed to conduct a simulation with some settings for a detailed comparison of these methods, focusing on scenarios where IVs are valid and under effect homogeneity with different instrument strengths. METHODS: We compared six IV methods under 32 simulation scenarios: two-stage least squares (2SLS), two-stage predictor substitutions (2SPS), two-stage residual inclusions (2SRI), limited information maximum likelihood (LIML), inverse-variance weighted methods with a linear outcome model (IVWLI ), and inverse-variance weighted methods with a non-linear model (IVWLL )...

Background There has been growing concern about the negative mental health impact of long working hours and overwork. Our study examined how work-life imbalance (WLI) could be a mediator between working hours and poor mental well-being.Methods We included 34,968 individuals from a nationwide cross-sectional survey in Korea. Self-reported working hours per week was collected, and mental health was assessed by the WHO-5 Well-Being Index. Counterfactual-based mediation models were employed to disentangle the total effects into a direct effect (work hour - poor mental health) and an indirect effect (work hour - WLI - poor mental health)...

No abstract text is available yet for this article.

BACKGROUND: Genetic epidemiological evidence for the kidney function traits in East Asian population including Japanese remain still relatively unclarified. Especially, the number of GWASs for kidney traits reported still remains limited, and the sample size of each independent study is relatively small. Given the genetic variability between ancestries/ethnicities, implementation of GWAS with sufficiently large sample sizes in specific population of Japanese is considered meaningful. METHODS: We conducted the GWAS meta-analyses of kidney traits by leveraging the GWAS summary data of the representative large genome cohort studies with about 200,000 Japanese participants (n = 202,406 for estimated glomerular filtration rate [eGFR] and n = 200,845 for serum creatinine [SCr])...

BACKGROUND: The influence of the coronavirus disease (COVID-19) pandemic on dental care utilization may have differed according to individual characteristics or type of dental care provision. This study aimed to evaluate the changes in dental care utilization and per-attendance costs by age group and type of dental care during the COVID-19 pandemic in Japan. METHODS: This time-series study used healthcare insurance claims data from 01/07/2019 to 09/27/2021 (143 weeks) from nine municipalities in Japan...

BACKGROUND: Behavioral and psychological symptoms of dementia (BPSD) are common among people with dementia from the early stages and can appear even in mild cognitive impairment (MCI). However, the prognostic impact of BPSD is unclear. This study examined the association between BPSD and mortality among people with cognitive impairment. METHODS: This longitudinal study involved 1,065 males and 1,681 females (mean age: males = 77.1 years; females = 78.6 years) with MCI or dementia diagnosis, from the National Center for Geriatrics and Gerontology-Life Stories of People with Dementia (NCGG-STORIES), a single-center memory clinic-based cohort study in Japan that registered first-time outpatients from 2010-2018...

Background Previous studies have suggested that employment insecurity is associated with adverse health outcomes. We explored the association between temporary employment and smoking behaviors.Methods We analyzed 11,795 workers (51,867 observations) from the Korea Health Panel Study (2009-2018). Employment types were categorized as regular, fixed-term, or daily, based on the duration of labor contract. The outcomes were current smoking status and changes in smoking behavior (initiation or cessation) in the following year...

BACKGROUND: The number of methamphetamine-related deaths has been increasing in recent decades. However, current data primarily rely on a few large-scale national surveys, highlighting the need for diverse data sources. Post-mortem studies offer advantages that compensate for the limitations of cohort studies. In this study, we aimed to (1) examine mortality rates and years of potential life lost, (2) compare proportionate mortality with previous cohort studies, and (3) quantitatively investigate causes of death as potential risk factors associated with each manner of death...

BACKGROUND: In Japan, few studies have examined suicide risk for five-year relative survival rates for cancer sites. Since five-year relative survival rates differ by sex, we aim to examine suicide risk for patients with cancer separately for men and women. METHODS: We estimated the risk of suicide among patients with cancer by sex in Japan compared to the general population, using standardized mortality ratios (SMRs). Patients with cancer diagnosed between January 1, 1985-December 31, 2013 and registered in the Osaka Cancer Registry were followed-up with for up to 10 years...

BACKGROUND: This study aimed to develop and validate claims-based algorithms for identifying hospitalized patients with coronavirus disease (COVID-19) and the disease severity. METHODS: We used claims data including all patients at the National Center for Global and Medicine Hospital between January 1, 2020, and December 31, 2021. The claims-based algorithms for three statuses with COVID-19 (hospitalizations, moderate or higher status, and severe status) were developed using diagnosis codes (ICD-10 code: U07...

No abstract text is available yet for this article.

BACKGROUND: The purpose of this study was to report the basic profile of the Miyagi Prefecture part of a repeated center-based survey during the second period (2nd period survey) of the Tohoku Medical Megabank Community-Based Cohort Study (TMM CommCohort Study), as well as the participants' characteristics based on their participation type in the baseline survey. METHODS: The 2nd period survey, conducted from June 2017 to March 2021, included participants of the TMM CommCohort Study (May 2013 to March 2016)...

No abstract text is available yet for this article.

BACKGROUND: A key measure of the effectiveness of end-of-life care is the place of death. The COVID-19 pandemic affected end-of-life care and the circumstances of patients with dementia. METHODS: This observational, retrospective cohort study used Japanese national data to examine the numbers and locations of reported deaths among patients with dementia older than 65 years during the COVID-19 pandemic. Locations were grouped as medical institutions, nursing facilities, homes, or all the above...

BACKGROUND: Radio-Taiso could be a sustainable public health strategy for maintaining quality of life (QoL) in older adults with frailty. This study aimed to investigate whether Radio-Taiso provided greater benefits for health-related quality of life (HR-QoL) and to identify the mechanisms underlying the effectiveness in this population. METHODS: A 12-week randomized controlled trial enrolled 226 older Japanese adults with pre-frailty or frailty, assessed using the modified frailty phenotype...

BACKGROUND: While coffee and green tea have been suggested to have immunoprotective effects, it remains elusive whether they can decrease the risk of COVID-19. OBJECTIVE: We prospectively examined the association between coffee and green tea consumption and the risk of COVID-19 among mRNA vaccine recipients during the epidemic of the Omicron variant. METHOD: Participants were 2,110 staff (aged 18 to 76 years) of a large medical facility in Tokyo, who attended a serosurvey in June 2022, predominatly received ≥3 doses of vaccine, and were followed for COVID-19 until December 2022...

BACKGROUND: The term "nonrestorative sleep (NRS)" refers to unrefreshed feeling at wake-up and is a domain of poor sleep quality. Previous researches have demonstrated that NRS is linked to a number of diseases and adverse health outcomes, but less is known regarding the link between NRS and diabetes, particularly in Japanese. METHODS: We studied 3665 middle-aged male participants of the Aichi Workers' Cohort Study who were followed-up from 2002 to 2019. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) of incident type 2 diabetes mellitus (T2DM) in relation to NRS adjusted for potential confounding variables...

No abstract text is available yet for this article.

BACKGROUND: The Japanese database of food composition was revised in 2020, during which both the number of food items and the number of food items measured for sugars, amino acids, and fatty acids were increased. We evaluated the validity of estimated intakes of sugars, amino acids and fatty acids using a long-food frequency questionnaire (FFQ) among middle-aged and elderly Japanese. METHODS: From 2012 to 2013, 240 men and women aged 40-74 years from five areas in the JPHC-NEXT protocol were asked to respond to the long-FFQ and provide a 12-day weighed food record (WFR) as reference...