Etsuji Suzuki

Sleep duration, sleep quality and cardiovascular disease mortality among the elderly: a population-based cohort study.

OBJECTIVE To investigate the associations between sleep duration and mortality in the elderly by controlling for sleep quality. METHOD Data were collected from participants in a cohort study in Shizuoka, Japan. A total of 14,001 elderly residents (aged 65-85 years), randomly chosen from all 74 municipalities in the prefecture, completed questionnaires that evaluated sleep duration, sleep complaints, and the use of hypnotics. Participants were followed from 1999 to 2006. We analyzed 11,395 subjects to estimate the hazard ratios (HR) for mortality from all causes and cardiovascular disease (CVD). RESULTS With 60,252 person-years, 1004 deaths were identified. While short sleep duration and mortality were not associated, longer sleep duration was associated with higher risk of mortality in both sexes. Compared with those who slept 7 h, the multivariate HR and 95% confidence interval of CVD mortality for those who slept > or =10 h was 1.95 (1.18-3.21) and, for those who slept < or =5 h, it was 1.10 (0.62-1.93). Although no clear association was found between sleep quality and mortality, long sleep duration was associated with higher risk of CVD mortality among those with poor sleep quality. CONCLUSION Long sleep duration is associated with higher risk of CVD mortality among the elderly with poor sleep quality.

Physical activity and mortality risk in the Japanese elderly: a cohort study.

BACKGROUND Physical activity recommendations for older adults with poor health needs to be understood. PURPOSE This study aims to examine the association between the frequency of physical activity and mortality among a sample of elderly subjects, most of whom were under treatment for pre-existing disease. METHODS Data on the frequency of leisure-time physical activity, walking for transportation, and non-exercise physical activity were obtained from a population-based cohort study in Shizuoka, Japan. Of the randomly selected 22,200 residents aged 65-84 years, 10,385 subjects were followed from 1999 to 2006 and analyzed. Hazard ratios (HRs) and 95% CIs were obtained for all-cause; cardiovascular disease (CVD); and cancer mortality, after adjusting for covariates such as pre-existing disease(s). A subgroup analysis that was restricted to subjects under treatment for pre-existing disease(s) at baseline was further conducted. Data were collected between 1999 and 2006, and all analyses were conducted in 2008 and 2009. RESULTS Every physical activity was associated with a reduced risk of all-cause and CVD mortality, among not only the total sample but even those under treatment. The HRs for CVD mortality among participants with 5 or more days of non-exercise physical activity per week for the total sample and those with pre-existing disease(s) were 0.38 (95% CI=0.22, 0.55) and 0.35 (95% CI=0.24, 0.52), respectively, compared with no non-exercise physical activity. The association between physical activity and cancer mortality was not clear. CONCLUSIONS This study suggests a protective effect of physical activity on all-cause and CVD mortality among Japanese elderly people with pre-existing disease.

Do bonding and bridging social capital have differential effects on self-rated health? A community based study in Japan

Background Few studies have examined the potential difference in the relationship between bonding versus bridging social capital and health outcomes. We sought to examine the association between these different types of social capital and self-rated health in a population-based study. Methods In February 2009, 4000 residents of Okayama City (aged 20–80 y) were randomly selected for a survey on social capital and health. The survey asked about participation in six different types of associations: Parents and Teachers Association, sports clubs, alumni associations, political campaign clubs, citizens groups and community associations. We distinguished between bonding and bridging social capital by asking participants about their perceived homogeneity (with respect to gender, age and occupation) of the groups they belonged to. ORs and 95% CIs for poor health were calculated. Results Bridging social capital (ie, participation in groups involving people from a diversity of backgrounds) was inversely associated with poor health in both sexes and women appeared to benefit more than men. Compared to those who reported zero participation, high bridging social capital was associated with a reduced odds of poor health (OR 0.25, 95% CI 0.11 to 0.55) in women after controlling for demographic variables, socioeconomic status, smoking habit and overweight. By contrast, bonding social capital was not consistently associated with better health in either gender. Conclusions The present study suggests that bonding and bridging social capital have differential associations with health and that the two forms of social capital need to be distinguished in considering interventions to promote health.

Does social capital promote physical activity? A population-based study in Japan.

BACKGROUND To examine the association between individual-level social capital and physical activity. METHODOLOGY/PRINCIPAL FINDINGS In February 2009, data were collected in a population-based cross-sectional survey in Okayama city, Japan. A cluster-sampling approach was used to randomly select 4,000 residents from 20 school districts. A total of 2260 questionnaires were returned (response rate: 57.4%). Individual-level social capital was assessed by an item inquiring about perceived trust of others in the community (cognitive dimension of social capital) categorized as low trust (43.0%), mid trust (38.6%), and high trust (17.3%), as well as participation in voluntary groups (structural dimension of social capital), which further distinguished between bonding (8.9%) and bridging (27.1%) social capital. Using logistic regression, we calculated the odds ratios (ORs) and 95% confidence intervals (CIs) for physical inactivity associated with each domain of social capital. Multiple imputation method was employed for missing data. Among total participants, 68.8% were physically active and 28.9% were inactive. Higher trust was associated with a significantly lower odds of physical inactivity (OR = 0.58, 95% CI = 0.42-0.79) compared with low trust. Both bridging and bonding social capital were marginally significantly associated with lower odds of physical inactivity (bridging, OR = 0.79, 95% CI = 0.62-1.00; bonding, OR = 0.71, 95% CI = 0.48-1.03) compared with lack of structural social capital. CONCLUSIONS/SIGNIFICANCE Low individual-level social capital, especially lower trust of others in the community, was associated with physical inactivity among Japanese adults.

Thyroid Cancer Detection by Ultrasound Among Residents Ages 18 Years and Younger in Fukushima, Japan: 2011 to 2014

Background: After the Great East Japan Earthquake and Tsunami in March 2011, radioactive elements were released from the Fukushima Daiichi Nuclear Power Plant. Based on prior knowledge, concern emerged about whether an increased incidence of thyroid cancer among exposed residents would occur as a result. Methods: After the release, Fukushima Prefecture performed ultrasound thyroid screening on all residents ages ⩽18 years. The first round of screening included 298,577 examinees, and a second round began in April 2014. We analyzed the prefecture results from the first and second round up to December 31, 2014, in comparison with the Japanese annual incidence and the incidence within a reference area in Fukushima Prefecture. Results: The highest incidence rate ratio, using a latency period of 4 years, was observed in the central middle district of the prefecture compared with the Japanese annual incidence (incidence rate ratio = 50; 95% confidence interval [CI] = 25, 90). The prevalence of thyroid cancer was 605 per million examinees (95% CI = 302, 1,082) and the prevalence odds ratio compared with the reference district in Fukushima Prefecture was 2.6 (95% CI = 0.99, 7.0). In the second screening round, even under the assumption that the rest of examinees were disease free, an incidence rate ratio of 12 has already been observed (95% CI = 5.1, 23). Conclusions: An excess of thyroid cancer has been detected by ultrasound among children and adolescents in Fukushima Prefecture within 4 years of the release, and is unlikely to be explained by a screening surge.

Green tea consumption and mortality among Japanese elderly people: the prospective Shizuoka elderly cohort.

PURPOSE To investigate the association between green tea consumption and mortality from all causes, cancer, and cardiovascular disease (CVD) among elderly people. METHODS In a population-based, prospective cohort study, a total of 14,001 elderly residents (aged 65-84 years), randomly chosen from all 74 municipalities in Shizuoka, Japan, completed questionnaires that included items about frequency of green tea consumption. They were followed for up to 6 years, from December 1999 to March 2006. Consequently, 12,251 subjects were analyzed to estimate the hazard ratios (HRs) for all-cause mortality, cancer, and CVD. RESULTS Among 64,002 person-years, 1,224 deaths were identified (follow-up rate, 71.6%). The multivariate HRs and 95% confidence intervals (CIs) for CVD mortality compared those who consumed seven or more cups per day with those who consumed less than one cup per day, were 0.24 (0.14-0.40), 0.30 (0.15-0.61), and 0.18 (0.08-0.40) for total participants, men, and women, respectively. Although green tea consumption was not inversely associated with cancer mortality, green tea consumption and colorectal cancer mortality were inversely associated with a moderate dose-response relationship. CONCLUSIONS Green tea consumption is associated with reduced mortality from all causes and CVD. This study also suggests that green tea could have protective effects against colorectal cancer.

Long-term exposure to traffic-related air pollution and mortality in Shizuoka, Japan

Objectives The number of studies investigating the health effects of long-term exposure to air pollution is increasing, however, most studies have been conducted in Western countries. The health status of Asian populations may be different to that of Western populations and may, therefore, respond differently to air pollution exposure. Therefore, we evaluated the health effects of long-term exposure to traffic-related air pollution in Shizuoka, Japan. Methods Individual data were extracted from participants of an ongoing cohort study. A total of 14 001 older residents, who were randomly chosen from all 74 municipalities of Shizuoka, completed questionnaires and were followed from December 1999 to March 2006. Individual nitrogen dioxide exposure data, as an index for traffic-related exposure, were modelled using a land use regression model. We assigned participants an estimated concentration of nitrogen dioxide exposure during 2000–2006. We then estimated the adjusted HR and their CI for a 10 μg/m3 increase in exposure to nitrogen dioxide for all-cause or cause-specific mortality. Results The adjusted HR for all-cause mortality was 1.02 (95% CI 0.96 to 1.08). Regarding cause-specific mortality, the adjusted HR for cardiopulmonary mortality was 1.16 (95% CI 1.06 to 1.26); in particular the adjusted HR for ischaemic heart disease mortality was 1.27 (95% CI 1.02 to 1.58) and for pulmonary disease mortality it was 1.19 (95% CI 1.02 to 1.38). Furthermore, among non-smokers, a 10 μg/m3 increase in nitrogen dioxide was associated with a higher risk for lung cancer mortality (HR 1.30, 95% CI 0.85 to 1.93). Conclusion Long-term exposure to traffic-related air pollution, indexed by nitrogen dioxide concentration, increases the risk of cardiopulmonary mortality, even in a population with a relatively low body mass index and increases the risk of lung cancer mortality in non-smokers.

Workplace Social Capital and All-Cause Mortality: A Prospective Cohort Study of 28 043 Public-Sector Employees in Finland

OBJECTIVES We examined the association between workplace social capital and all-cause mortality in a large occupational cohort from Finland. METHODS We linked responses of 28 043 participants to surveys in 2000 to 2002 and in 2004 to national mortality registers through 2009. We used repeated measurements of self- and coworker-assessed social capital. We carried out Cox proportional hazard and fixed-effects logistic regressions. RESULTS During the 5-year follow-up, 196 employees died. A 1-unit increase in the mean of repeat measurements of self-assessed workplace social capital (range 1-5) was associated with a 19% decrease in the risk of all-cause mortality (age- and gender-adjusted hazard ratio [HR] = 0.81; 95% confidence interval [CI] = 0.66, 0.99). The corresponding point estimate for the mean of coworker-assessed social capital was similar, although the association was less precisely estimated (age- and gender-adjusted HR = 0.77; 95% CI = 0.50, 1.20). In fixed-effects analysis, a 1-unit increase in self-assessed social capital across the 2 time points was associated with a lower mortality risk (odds ratio = 0.81; 95% CI = 0.55, 1.19). CONCLUSIONS Workplace social capital appears to be associated with lowered mortality in the working-aged population.

Evaluation of an internet-based self-help program for better quality of sleep among Japanese workers: a randomized controlled trial.

Evaluation of an Internet‐Based Self‐Help Program for Better Quality of Sleep among Japanese Workers: A Randomized Controlled Trial: Etsuji Suzuki, et al. Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences—The effectiveness of Internet‐based self‐help programs for insomnia is still unclear. A randomized controlled trial was conducted to evaluate the effect of an Internet‐based self‐help program for better quality of sleep among adult workers. Forty‐three volunteers were recruited and randomly assigned to either an intervention group (n=21) or a waiting‐list group (n=22). The intervention group participated in a two‐week Internet‐based program, including selecting and daily practicing sleep‐related target behaviors and monitoring those behaviors along with sleep quality. At the same time, each participant received automatically generated, personalized messages and reports both daily and weekly. A total of 12 intervention group participants and 18 waiting‐list group participants completed questionnaires at baseline, post‐intervention, and at a 3‐wk follow‐up. Subjective sleep quality was measured by a self‐reported questionnaire developed for this study. The sleep quality score increased in the intervention group at post‐intervention, with a significant interaction effect [F(1,28)=5.19, p=0.031]. Sleep‐related behaviors also greatly increased in the intervention group at post‐intervention, with a significant interaction effect [F(1,28)=7.14, p=0.012]. Sleep‐onset latency reduced in the intervention group at follow‐up, with a marginally significant effect [F(1,28)=3.52, p=0.071]. The Internet‐based self‐help program improves subjective sleep quality and sleep‐onset latency among adult workers.

Multi-level, cross-sectional study of workplace social capital and smoking among Japanese employees

BackgroundSocial capital is hypothesized to be relevant to health promotion, and the association between community social capital and cigarette smoking has been examined. Individual-level social capital has been found to be associated with smoking cessation, but evidence remains sparse on the contextual effect of social capital and smoking. Further, evidence remains sparse on the association between smoking and social capital in the workplace, where people are spending an increasing portion of their daily lives. We examined the association between workplace social capital and smoking status among Japanese private sector employees.MethodsWe employed a two-stage stratified random sampling procedure. Of the total of 1,800 subjects in 60 companies, 1,171 (men/women; 834/337) employees (65.1%) were identified from 46 companies in Okayama in 2007. Workplace social capital was assessed in two dimensions; trust and reciprocity. Company-level social capital was based on inquiring about employee perceptions of trust and reciprocity among co-workers, and then aggregating their responses in order to calculate the proportion of workers reporting mistrust and lack of reciprocity. Multilevel logistic regression analysis was conducted using Markov Chain Monte Carlo methods to explore whether individual- and company-level social capital was associated with smoking. Odds ratios (ORs) and 95% credible intervals (CIs) for current smoking were obtained.ResultsOverall, 33.3% of the subjects smoked currently. There was no relationship between individual-level mistrust of others and smoking status. By contrast, one-standard deviation change in company-level mistrust was associated with higher odds of smoking (OR: 1.25, 95% CI: 1.06-1.46) even after controlling for individual-level mistrust, sex, age, occupation, educational attainment, alcohol use, physical activity, body mass index, and chronic diseases. No clear associations were found between lack of reciprocity and smoking both at the individual- and company-level.ConclusionsCompany-level mistrust is associated with higher likelihood of smoking among Japanese employees, while individual perceptions of mistrust were not associated. The link between lack of reciprocity and smoking was not supported either at the individual- or company-level. Further studies are warranted to examine the possible link between company-level trust and smoking cessation in the Japanese workplace.