Journal of Epidemiology最新文献

Background: Healthy life expectancy (HLE) is a population health indicator that is widely used in developed countries, but little is known about its relationships with combinations of non-communicable disease risk factors. This study was conducted to examine HLE at age 65 years according to combinations of blood pressure levels, body mass index, smoking status, and diabetes mellitus (DM) in a Japanese population.

Methods: In a nationwide cohort study (NIPPON DATA90), data on these risk factors were obtained from participants in 1990 through physical examinations, blood tests, interviews, and questionnaires. Subsequently, participants aged ≥65 years underwent surveys on activities of daily living in 1995 and 2000, and multistate life tables were used to calculate combination-specific HLEs and their 95% confidence intervals (CIs).

Results: The study population comprised 6,569 participants (men: 2,797; women: 3,772) who were followed until 2010. HLE at age 65 years in men with grade II/III hypertension, obesity, current smoker status, and DM (HLE 12.9; 95% CI, 12.9-13.0 years) was 9.7 years shorter than men without these risk factors (HLE 22.6; 95% CI, 22.4-22.8 years). Similarly, HLE at age 65 years in women with grade II/III hypertension, obesity, current smoker status, and DM (HLE 16.2; 95% CI, 15.9-16.5 years) was 10.1 years shorter than women without these risk factors (HLE 26.3; 95% CI, 26.3-26.3 years).

Conclusion: The large discrepancies in HLEs underscore the impact of non-communicable disease risk factors, which should be considered when formulating health interventions to improve HLE in Japanese older adults.

Background: Studies have shown that informal caregiving is associated with an increased risk of cardiovascular diseases. However, there is limited evidence on the mechanisms involved. To fill this knowledge gap, we investigated the association of informal caregiving with changes in health-related behaviors.

Methods: We analyzed a nationally representative sample aged 50-59 years as of 2005 using fifteen waves of the Longitudinal Survey of Middle-Aged and Older Adults, which was conducted between 2005-2019. We investigated the association between the change in informal caregiving status and the change in health-related behaviors, including (1) heavy drinking, (2) smoking, (3) no exercise habits, and (4) no attendance at annual health checkups. We used multivariable logistic regression models with correlated random effects, adjusting for individual-level time-invariant characteristics.

Results: Among 268,165 observations from 30,530 participants (median age 55; interquartile range, 52-57 years at baseline; 51.6% women), 32,164 (12.0%) observations from 10,224 individuals provided informal care. After adjusting for potential confounders, informal caregiving was associated with higher probabilities of deteriorating health-related behaviors, including heavy drinking (adjusted odds ratio [aOR] 1.16; 95% confidence interval [CI], 1.03-1.32; adjusted P = 0.032) and no exercise habits (aOR 1.09; 95% CI, 1.04-1.15; adjusted P < 0.001). We observed similar patterns for smoking (aOR 1.12; 95% CI, 1.001-1.26; adjusted P = 0.053) and no attendance at health checkups (aOR 1.05; 95% CI, 0.999-1.10; adjusted P = 0.053).

Conclusion: This study showed that the transition into informal caregiving was associated with deteriorating cardiovascular-related health behaviors in Japan. These findings highlighted the importance of continued efforts to prevent the deterioration of caregivers' health-related behaviors.

Background: Poor dietary habits are a significant changeable factor contributing to negative health effects; however, the connection between variations in dietary diversity over time and mortality remains uncertain. This study aimed to evaluate the association between longitudinal changes in the dietary diversity score (DDS) and mortality in Japanese adults.

Methods: This prospective study included 20,863 adults (13,144 women, 7,719 men) aged 40-79 years from the Japan Collaborative Cohort Study. The DDS was evaluated twice, once at baseline and again 5 years later, using a validated food frequency questionnaire that assessed 33 food items. Participants were classified into four groups based on mean DDS: baseline low DDS/5 years later low DDS (n = 7,866; Low/Low group), baseline low DDS/5 years later high DDS (n = 2,951; Low/High group), baseline high DDS/5 years later low DDS (n = 3,000; High/Low group), and baseline high DDS/5 years later high DDS (n = 7,046; High/High group). Survival data were collected until 2009, and hazard ratios (HRs) for mortality were calculated using a Cox proportional hazards model.

Results: During a median follow-up of 14.8 years (256,277 person-years), 2,995 deaths were documented. After adjusting for confounders, participants in the High/High group had a lower HR for mortality from all causes (HR 0.82; 95% confidence interval [CI], 0.74-0.91) and cardiovascular disease (HR 0.81; 95% CI, 0.67-0.98) than those in the Low/Low group. Similar associations were observed with dairy, soy, and vegetables/fruits, but they were validated exclusively in women.

Conclusion: This study showed that maintaining a higher DDS may be associated with lower mortality in women.

Background: While evidence from Western countries links low-to-moderate alcohol consumption to a lower risk of type 2 diabetes mellitus (T2D), findings have been inconsistent in Asia. Since T2D in Asia involves both insulin resistance and deficient insulin secretion, both of which are differently affected by alcohol, we prospectively examined whether the association differs according to body mass index (BMI) categories among the Japanese.

Methods: Participants were 31,524 health checkup examinees (26,819 males and 4,705 females aged 20-64 years) who were free from diabetes at baseline. Self-reported data on alcohol use were used to estimate the average daily alcohol consumption at the baseline. Incident diabetes was identified at annual checkups during the follow-up period. A Cox proportional hazards model was used to estimate hazard ratios and 95% confidence intervals.

Results: During a median follow-up of 12.0 years, 3,527 male and 287 female participants developed T2D. The association between alcohol consumption and T2D risk differed markedly by BMI in both sexes. Among males, low- and moderate-level alcohol consumption was associated with a lower T2D risk in individuals with BMI ≥25.0 kg/m², whereas consumption at a level of 2 go/day (approximately 46 g ethanol) was linked to an increased T2D risk in those with BMI ≤22.0 kg/m². In females, similar patterns were observed, although confidence intervals were broad due to the smaller sample size.

Conclusion: In Japan, low-to-moderate alcohol consumption may lower T2D risk in those with excess body weight, while high alcohol consumption may increase T2D risk in those with lower BMI.

Background: Non-random participation can undermine the representativeness of seroepidemiological surveys. Despite their critical role in estimating disease spread during pandemics, non-response bias and methods to correct it require further investigation. This study aimed to examine sociodemographic characteristics and COVID-19-related factors influencing participation in a seroepidemiological survey.

Methods: We analyzed data from a national COVID-19 seroepidemiological survey in Japan between December 2022 and March 2023. We performed multivariable logistic regression analyses to estimate adjusted odds ratios (AOR) and their confidence intervals (CIs) after variable selection with the Group Least Absolute Shrinkage and Selection Operator.

Results: Among 6,091 participants, factors associated with higher odds of seroepidemiological surveys participation included being female (AOR 2.08 [95% CI, 1.25-3.47]), living in larger households versus living alone (two: 2.34 [1.20-4.55]; four or above: 2.05 [1.03-4.06]), higher education levels versus junior high school education (high school: 2.66 [1.06-6.15]; junior colleges, technical colleges, vocational schools: 5.51 [1.94-15.07]; university and above: 3.30 [1.26-7.98]), and having a higher household income versus earning <2 million yen (2-4 million yen: 3.32 [1.52-7.33]; 4-6 million yen: 2.73 [1.2-6.23], ≥6 million yen: 4.51 [1.91-10.59]). Lower seroepidemiological survey participation odds were observed in those hesitant or unwilling to vaccinate (0.16 [0.09-0.29]) and those perceiving a higher COVID-19 positivity rate among close contacts (0.98 [0.98-0.99]).

Conclusions: Education, income, household size, sex, vaccination status, and perceived infection risk influenced seroepidemiological survey participation. The findings highlight the need to account for non-response bias using weighted methods like inverse probability weighting.

Background: Studies on the association between multimorbidity and mortality in large populations have mainly been conducted in European and North American populations. This study aimed to identify the association between cardiometabolic multimorbidity and all-cause and cardiovascular disease (CVD) mortality in the Asia Cohort Consortium.

Methods: In this prospective cohort study, pooled analysis was performed to evaluate the association between cardiometabolic diseases (hypertension, diabetes, ischemic heart disease, and stroke), multimorbidity, and all-cause and CVD mortality, including premature mortality, among participants from 11 Asian cohort studies. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox hazard regression.

Results: A total of 483,532 participants were followed for a median of 14.3 years. Compared with participants without any disease, those with stroke and diabetes had higher age- and sex-adjusted HRs for all-cause mortality (HR 3.9; 95% CI, 3.28-4.56). Moreover, the age- and sex-adjusted HRs for CVD mortality were highest in participants with stroke, ischemic heart disease, and diabetes (HR 10.6; 95% CI, 6.16-18.25). These patterns remained consistent after additional adjustments for smoking status and body mass index. The risk of premature mortality followed similar trends but was more pronounced.

Conclusion: These findings highlight the differential impacts of individual cardiometabolic diseases and their combinations on mortality risks. Stroke and diabetes were associated with the highest risks for all-cause and cardiovascular mortality, underscoring the need for targeted prevention and personalized management strategies tailored to these high-risk conditions in Asian populations.

Background: The Tohoku Medical Megabank Project has initiated the Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study) including genomic and omics investigations and conducted a self-administered food frequency questionnaire with the response option "constitutionally unable to eat or drink it" for individual food items (TMM-FFQ) for pregnant women. This study evaluated the validity of the TMM-FFQ among pregnant women.

Methods: Participants comprised 122 pregnant women aged ≥20 years residing in Miyagi Prefecture who completed weighed food records (WFRs) for 3 days as reference intake and the TMM-FFQ during mid-pregnancy. Correlations between nutrient or food group intakes based on the WFR and the TMM-FFQ were calculated using Spearman's rank correlation coefficients (CCs), adjusting for energy intake and correcting for random within-individual variation of WFR. Cross-classification was also conducted according to quintiles using the WFR and TMM-FFQ data.

Results: The percentages of participants who chose the "constitutionally unable to eat or drink it" option were >3% for seven food and drink items. CCs were >0.30 for 31 nutrients; the median across energy and 44 nutrients was 0.41. CCs were >0.30 for 14 food groups; the median across 20 food groups was 0.35. The median percentages of cross-classification into exact plus adjacent quintiles and extreme quintiles were 63.1% and 3.3% for energy and nutrients and 61.9% and 4.1% for food groups, respectively.

Conclusion: The validity of the TMM-FFQ compared with the WFR was reasonable for certain nutrients and food groups among pregnant women in the TMM BirThree Cohort Study.

Background: Evidence of post-COVID-19 condition (PCC) in the Alpha- and Delta-variant dominant waves is limited.

Methods: In a nationwide multicenter cohort study in collaboration with 20 hospitals, we collected data using self-administered questionnaires and electronic medical records of participants aged 20 or more diagnosed with COVID-19, hospitalized between April 1, 2021 and September 30, 2021, and discharged alive. Descriptive statistics were analyzed for PCC and mental health (HADS anxiety and depression scores), comparing Alpha- and Delta-variant dominant waves.

Results: We analyzed 1,040 patients (median age, 57 [IQR 49-66] years; men, 66.2%). Of the respondents, 45.4% had at least one PCC symptom 1 year after infection. The common symptoms included dyspnea (20.7%), fatigue/malaise (17.6%), muscle weakness (15.4%), decrease in concentration (13.4%), and sleep disorder (13.3%), followed by brain fog (8.4%). Among patients with PCC, 14.0% had anxiety (HADS-Anxiety ≥11), and 18.6% had depression (HADS-Depression ≥11), with four times higher proportions than those without PCC; only small variations by age, sex, and waves were observed. Associated factors for PCC were age 40 years or over, women, severity of COVID-19 during hospitalization, ex-smokers who quit smoking before COVID-19 infection and being infected during the Delta-variant dominant wave.

Conclusion: The study described the prevalence of PCC, associated factors, and mental health of COVID-19 survivors hospitalized during the Alpha- and Delta-variant dominant waves in Japan. Further follow-up will be conducted to examine the longer-term impact of COVID-19 on PCC, complications, daily life, and socioeconomic status.

Background: We launched the Wako Cohort Study in 2023 to identify individual and socio-environmental factors related to the extension of healthy life expectancy and the reduction of health disparities among community-dwelling adults and to develop health promotion and care prevention strategies. This study profile aims to describe the study design and participants' profile at baseline.

Methods: The Wako Cohort Study is a prospective study of community-dwelling adults aged ≥40 years living in Wako City, Saitama Prefecture, Japan. The Wako Cohort Study consists of two surveys: a mail-in survey for persons aged ≥40 years and a face-to-face assessment (on-site survey) for those aged ≥65 years. The survey items were designed considering the following points: 1) life course perspective (transition from middle to old age in the life course), 2) health indifference, and 3) employment in older age.

Results: A total of 8,824 individuals participated in the mail-in survey (2,395 persons aged 40-64 years and 6,429 aged ≥65 years). Of those aged ≥65 years who returned the mail survey, 1,004 participated in the subsequent on-site survey. Men aged ≥65 years tended to have higher health interests than those aged 40-64 years; however, this was not true for women. In the mail-in survey, 30.4% of those aged ≥65 years were employed.

Conclusion: The Wako Cohort Study is expected to provide new insights into the development of strategies to extend healthy life expectancy and reduce health disparities in Japan.