Journal of Epidemiology最新文献

In epidemiological or clinical studies with follow-ups, data tables generated and processed for statistical analysis are often of the "wide-format" type-consisting of one row per individual. However, depending on the situation and purpose of the study, they may need to be transformed into the "long-format" type-which allows for multiple rows per individual. This tutorial clarifies the typical situations wherein researchers are recommended to split follow-up times to generate long-format data tables. In such applications, the major analytical aims consist of (i) estimating the outcome incidence rates or their ratios between ≥ 2 groups, according to specific follow-up time periods; (ii) examining the interaction between the exposure status and follow-up time to assess the proportional hazards assumption in Cox models; (iii) dealing with time-varying exposures for descriptive or predictive purposes; (iv) estimating the causal effects of time-varying exposures while adjusting for time-varying confounders that may be affected by past exposures; and (v) comparing different time periods within the same individual in self-controlled case series analyses. This tutorial also discusses how to split follow-up times according to their purposes in practical settings, providing example codes in Stata, R, and SAS.

Background: Informal caregiving of older parents adversely affects the mental health of family caregivers. However, the psychological effects of caregiving cessation and the trajectories of these effects have rarely been examined in Japan. This study addresses this gap.

Methods: Based on a 17-wave nationwide population-based survey in Japan, we analyzed longitudinal data from 8,280 individuals aged 50-59 years in 2005 who started caring for their older parents in 2006 or later and ceased caregiving by 2021. We identified the timings of caregiving onset and cessation and examined the trajectory of psychological distress (PD), defined as a Kessler score ≥ 5 on the 6-item Kessler scale (range 0-24). Linear mixed models were used to assess the trajectory of PD that evolved after caregiving cessation over the subsequent three years.

Results: After adjusting for covariates, the probability of PD decreased by 5.6 percentage points (from 40.8%; 95% confidence interval [CI], 4.1-7.0) for female caregivers and by 1.9 percentage points (from 31.7%; 95% CI, 0.3-3.5) for male caregivers at caregiving cessation, remaining stable in subsequent years. For women, higher PD risks related to co-residence with a care recipient diminished quickly upon cessation of caregiving, while the unfavorable impacts of no social activity, extended duration of care, and long-hour daily care persisted in subsequent years. For male caregivers, the impact was generally more limited.

Conclusions: These results suggest that changes in mental health following caregiving cessation warrant serious consideration when developing support programs for former family caregivers.

BackgroundParents' educational background is presumed to influence the incidence of vaccine-preventable diseases in children through their decisions about vaccinations and other family lifestyle choices. Regarding voluntary vaccination, a household's economic situation may also be associated with non-vaccination. Therefore, this study investigated the association between parental education and vaccine-preventable diseases (varicella, mumps, influenza [flu], pertussis, measles, and rubella) in children, which currently remains elusive.MethodsWe used datasets from the Japan Environment and Children's Study, which included 104,062 fetal records; our study population comprised 80,930 children up to the age of three years. The associations between parental educational background and children's infectious diseases were examined using binomial logistic regression analysis. The mediating effects of household income, vaccination, and smoking were examined using a path analysis.ResultsFor varicella, mumps, and influenza covered by voluntary vaccination, a higher education level of the father was associated with a lower incidence of infection. The association between mothers' education and children's infection was limited. There were both income-mediated and non-income-mediated pathways between parental education and voluntary vaccination. For pertussis, measles, and rubella, which are covered by routine vaccines, there was no association between parental education and the child's infection.ConclusionAn association between parental education and childhood infections was observed. Additionally, providing financial support for vaccination and communicating the benefits of vaccination in a way that parents at all levels of education can understand will help reduce the incidence of infectious diseases among children.

Background: The burden of cancer in India has been rising, yet testing for early detection remains low. This study explored inequalities in the uptake of breast cancer (BC) examination and cervical cancer (CC) among Indian women, focusing on socioeconomic, regional, and educational differences.

Methods: Data from the 2019-21 National Family Health Survey (n=353,518) were used to assess the uptake of BC examination and CC testing. Inequalities were quantified using the slope index of inequality (SII), relative index of inequality (RII), and relative concentration index (RCI). SII measured absolute inequality, while RII and RCI assessed relative inequality between disadvantaged and advantaged groups.

Results: The ever uptake of tests for early detection of BC and CC were low at 9 and 20 per 1,000 women, respectively. Higher uptake was observed among women from the richest households compared to the poorest (SII: 1.1 for BC and 1.8 for CC). The magnitude of relative socioeconomic inequalities was more pronounced in rural areas (RCI: 22.5 for BC and 21.3 for CC) compared to urban areas. Similarly, higher-educated women were 4.84 times (RII: 4.84) and 2.12 times (RII: 2.12) more likely to undergo BC examination and CC testing, respectively, compared to non-educated women. The northeastern region exhibited greater socioeconomic inequality, while the western region showed more education-based inequality.

Conclusion: The lower uptake of BC examination and CC testing and the marked inequalities underscore the need for targeted interventions to improve access and utilization of testing services, especially among lower-educated women, and those in rural areas.

Background: While coffee and green tea have been suggested to have immunoprotective effects, it remains elusive whether they can decrease the risk of coronavirus disease 2019 (COVID-19).

Objective: We prospectively examined the associations of coffee and green tea consumption with the risk of COVID-19 among mRNA vaccine recipients during the epidemic of the Omicron variant.

Methods: Participants were 2,110 staff (aged 18 to 76 years) of a large medical facility in Tokyo, who attended a serosurvey in June 2022, predominantly received ≥3 doses of vaccine, and were followed for COVID-19 until December 2022. Coffee and green tea consumption was ascertained via a questionnaire. COVID-19 was identified through the in-house registry. Cox proportional hazards model was used to estimate the hazard ratios (HRs) of COVID-19 across the categories of beverage consumption.

Results: During 6 months of follow-up, 225 (10.6%) cases of COVID-19 were identified. Contrary to the expectation, higher consumption of coffee was associated with a significant increase in the risk of COVID-19; multivariable-adjusted HRs were 1.00 (reference), 0.92 (95% confidence interval [CI], 0.62-1.35), 1.48 (95% CI, 0.99-2.22), and 1.82 (95% CI, 1.20-2.76) for <1 cup/day, 1 cup/day, 2 cups/day, and ≥3 cups/day, respectively (P trend = 0.003). Green tea consumption was not significantly associated with the risk of COVID-19. The association with coffee was attenuated if serologically detected infection was added to the cases.

Conclusion: In a cohort of Japanese hospital staff who received COVID-19 vaccine, higher consumption of coffee was associated with an increased risk of COVID-19 during the epidemic of the Omicron variant. There was no evidence of a significant association between green tea consumption and COVID-19 risk.

Background: The term "nonrestorative sleep (NRS)" refers to an unrefreshed feeling at wake-up and is a domain of poor sleep quality. Previous research has 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 3,665 middle-aged male participants of the Aichi Workers' Cohort Study who were followed-up from 2002 through 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.

Results: During a median follow-up of 14.6 years, 421 type 2 diabetes cases were identified. Participants with NRS had a higher crude incidence rate of T2DM (11.2/1,000 person-years), compared to participants without NRS (9.3/1,000 person-years). In the fully adjusted model, individuals who reported having NRS had a significantly higher risk of developing T2DM (HR1.36; 95% CI, 1.10-1.67). The association was observed only in participants under 50 years old (HR 1.82; 95% CI, 1.36-2.43), not in the older (50 years or older) participants (P for interaction = 0.025). In contrast, stratified analyses by the presence of shift work, obesity, or sleep duration showed similar associations in all the strata.

Conclusion: NRS was associated with higher risk of T2DM in middle-aged Japanese male workers independent of a variety of lifestyle factors and other sleep problems.

Background: Heated tobacco products (HTPs) have gained global popularity, but their health risks remain unclear. Therefore, the current study aimed to identify plasma metabolites associated with smoking and HTP use in a large Japanese population to improve health risk assessment.

Methods: Metabolomics data from 9,922 baseline participants of the Tsuruoka Metabolomics Cohort Study (TMCS) were analyzed to determine the association between smoking habits and plasma metabolites. Moreover, alterations in smoking-related metabolites among HTP users were examined based on data obtained from 3,334 participants involved from April 2018 to June 2019 in a follow-up survey.

Results: Our study revealed that cigarette smokers had metabolomics profiles distinct from never smokers, with 22 polar metabolites identified as candidate biomarkers for smoking. These biomarker profiles of HTP users were closer to those of cigarette smokers than those of never smokers. The concentration of glutamate was higher in cigarette smokers, and biomarkers involved in glutamate metabolism were also associated with cigarette smoking and HTP use. Network pathway analysis showed that smoking was associated with the glutamate pathway, which could lead to endothelial dysfunction and atherosclerosis of the vessels.

Conclusion: Our study showed that the glutamate pathway is affected by habitual smoking. These changes in the glutamate pathway may partly explain the mechanism by which cigarette smoking causes cardiovascular disease. HTP use was also associated with glutamate metabolism, indicating that HTP use may contribute to the development of cardiovascular disease through mechanisms similar to those in cigarette use.

Background: Although both a lower and a higher body mass index (BMI) are reportedly associated with head and neck cancer (HNC), reports from Asia are scarce. Moreover, evidence regarding the association between height and HNC is limited.

Methods: We investigated associations between BMI, height, and the incidence of HNC among 102,668 participants (49,029 men and 53,639 women) aged 40-69 years in the Japan Public Health Center-based Prospective Study. We followed participants from 1990 to 2013. We conducted a Cox proportional hazards regression analysis, which included adjustment for potential confounders such as smoking status. Baseline weight and height information were self-reported.

Results: Over an average follow-up of 18.7 years, 311 HNC cases were newly diagnosed. Lower BMI was significantly associated with HNC, with hazard ratios [HR] of 2.75 (95% confidence interval [CI]: 1.63-4.64) for <18.5 kg/m² and 1.63 (95% CI=1.15-2.30) for 18.5-20.9 kg/m² compared to 23-24.9 kg/m². Increased risk was suggested for higher BMI, with an HR of 1.30 (95%CI=0.84-2.00) for ≥27.5 kg/m². This trend was also observed in quadratic models. Results were similar among never smokers. Meanwhile, only lower BMI showed a strong association with HNC risk among former and current smokers (HR: 3.09, 95%CI: 1.54-6.20 for <18.5 kg/m² compared to 23 to 24.9 kg/m²). Height showed no association with HNC.

Conclusions: Lower BMI was significantly associated with HNC risk, while increased HNC risk was suggested in higher BMI among never smokers. Among former and current smokers, only lower BMI was associated with HNC risk.

Background: The health statuses of closely connected individuals are interdependent. Little is known about mortality risk associated with partner's cancer diagnosis and cause-specific mortality risk associated with partner's death.

Methods: Relative risks for all-cause and cause-specific mortality following a partner's cancer diagnosis or death compared to the period when the partner is cancer-free and alive were investigated in the population-based prospective cohort study that enrolled 140,420 people at the age between 40-69 in 1990-1994.

Results: 55,050 participants (27,665 men and 27,385 women) who were identified as married couples were followed-up for 1,073,746.1 (518,368.5 in men and 555,377.6 in women) person-years, during which 9,816 deaths (7,217 in men and 2,599 in women) were observed. After a partner's cancer diagnosis, the mortality rate ratio (MRR) of all-cause mortality was not increased among both men and women, while an increase of externally-caused MRR was observed. The suicide MRR significantly increased among men (MRR = 2.90 [95% CI, 1.70-4.93]) and it persisted for more than 5 years. After a partner's death, the MRRs of all-cause, cardiovascular disease (CVD), respiratory disease (RD), and externally-caused mortality significantly increased only among men. Stratified analysis by smoking status among men showed significantly increased MRRs of CVD and RD mortality among former/current smokers, but not among never-smokers.

Conclusion: Partner's cancer diagnosis did not increase all-cause mortality risk, but increased externally-caused mortality risk, especially suicide among men. The impact of partner's death on mortality risk differed by the mortality causes and sex, and smoking affected some of cause-specific mortality risk.