Sedentary bout durations and metabolic syndrome among working adults: a prospective cohort study.

BACKGROUND: This study aimed to examine the associations between time spent in prolonged and non-prolonged sedentary bouts and the development of metabolic syndrome. METHODS: We used data from a prospective study of Japanese workers. Baseline examination was conducted between 2010 and 2011. A total of 430 office workers (58 women) aged 40-64 years without metabolic syndrome were followed up by annual health checkups until 2014. Metabolic syndrome was defined as having ≥ 3 out of 5 diagnostic criteria from the Joint Interim Statement 2009 definition. Sedentary time was assessed using a tri-axial accelerometer. Time spent in total, prolonged (accumulated ≥ 30 min) and non-prolonged sedentary bouts (accumulated < 30 min) was calculated. Cox proportional hazards models were used to estimate the risk of developing metabolic syndrome. RESULTS: During a median follow-up of 3 years, 83 participants developed metabolic syndrome. After adjustment for age, sex, education, smoking, and family income, positive associations were observed between time spent in prolonged sedentary bouts and the development of metabolic syndrome. After additional adjustment for moderate-to-vigorous physical activity, those in the three highest quartiles of time spent in prolonged sedentary bouts showed higher risk of metabolic syndrome compared to the lowest quartile group, with adjusted hazard ratios (95 % confidence intervals) of 2.72 (1.30 - 5.73), 2.42 (1.11 - 5.50), and 2.85 (1.31 - 6.18), respectively. No associations were seen for time spent in total and non-prolonged sedentary bouts. CONCLUSIONS: Sedentary behavior accumulated in a prolonged manner was associated with an increased risk of metabolic syndrome. In devising public health recommendations for the prevention of metabolic disease, the avoidance of prolonged uninterrupted periods of sedentary behavior should be considered.

The Impact of Sleep Timing, Sleep Duration, and Sleep Quality on Depressive Symptoms and Suicidal Ideation amongst Japanese Freshmen: The EQUSITE Study.

Aim. The aim of this study was to identify the impact of bedtime, wake time, sleep duration, sleep-onset latency, and sleep quality on depressive symptoms and suicidal ideation amongst Japanese freshmen. Methods. This cross-sectional data was derived from the baseline survey of the Enhancement of Q-University Students Intelligence (EQUSITE) study conducted from May to June, 2010. A total of 2,631 participants were recruited and completed the following self-reported questionnaires: the Pittsburgh Sleep Quality Index (PSQI), the Center for Epidemiologic Studies Depression Scale (CES-D), and the original Health Support Questionnaires developed by the EQUSITE study research team. Results. Of 1,992 participants eligible for analysis, 25.5% (n = 507) reported depressive symptoms (CES-D total score ≥ 16), and 5.8% (n = 115) reported suicidal ideation. The present study showed that late bedtime (later than 01:30), sleep-onset latency (≥30 minutes), and poor sleep quality showed a marginally significant association with depressive symptoms. Poor sleep quality was seen to predict suicidal ideation even after adjusting for depressive symptoms. Conclusion. The current study has important implications for the role of bedtime in the prevention of depressive symptoms. Improving sleep quality may prevent the development of depressive symptoms and reduce the likelihood of suicidal ideation.

Association between participation in social activity and physical fitness in community-dwelling older Japanese adults.

Purpose This study aimed to examine the relationship between participation in social activity and both, composite and individual measures of physical fitness in community-dwelling older adults.Methods This study was conducted using baseline data from the Sasaguri Genkimon Study (SGS), a longitudinal cohort study conducted in 2011. Participants were 1,365 community-dwelling men and women aged 65 years or above, who did not require certified nursing care and who resided in Sasaguri, a town located east of the Fukuoka metropolitan area. Participation in social activity was assessed by asking participants whether they engaged in any of eight social activities. Physical fitness tests assessed participants' handgrip strength and knee extension strength as measures of muscle strength, and their one-leg standing time, 5-m maximum gait speed, and 5-repetition sit-to-stand rate as measures of their physical performance. Multiple linear regression and logistic regression analyses were conducted to assess the relationship between participation in social activity and each measure of physical fitness, adjusting for sex; age; body mass index; socioeconomic status; solitary living; exercise, habitual drinking and smoking; accelerometer-measured, moderate-to-vigorous physical activity; cognitive function; instrumental activities of daily living; distress; social network; and comorbidities.Results A total of 83.6% of the participants were engaged in at least one social activity. After adjusting for potential confounders, engagement in social activity was positively associated with a higher composite physical fitness score, faster gait speed and 5-repetition sit-to-stand rate, and longer one-leg standing time (P=0.008, P=0.030, P=0.034, and P=0.009, respectively).Conclusion Participation in social activity was significantly associated with physical fitness, specifically those related to locomotive function. These associations were independent of various confounders including socioeconomic status, and comorbidities.

Associations of Sedentary Time and Breaks in Sedentary Time With Disability in Instrumental Activities of Daily Living in Community-Dwelling Older Adults.

BACKGROUND: This cross-sectional study was performed to examine associations of objectively measured sedentary time (ST) and breaks in sedentary time (BST) with instrumental activities of daily living (IADL) disability in Japanese community-dwelling older adults. METHODS: The sample comprised 1634 older adults (mean age: 73.3 y, men: 38.4%). Sedentary behavior was measured using a triaxial accelerometer. Disability was defined as inability in at least 1 of the IADL tasks using the Tokyo Metropolitan Institute of Gerontology Index of Competence. RESULTS: After adjusting for potential confounders and moderate-to-vigorous physical activity (MVPA), longer ST was significantly associated with higher likelihood of IADL disability, whereas a greater number of BST was associated with lower likelihood of IADL disability. ST and BST remained statistically significant after mutual adjustment with odds ratio of 1.30 (95% confidence interval [CI)], 1.00-1.70) and 0.80 (95% CI, 0.65-0.99), respectively. CONCLUSIONS: This study first demonstrated that shorter ST and more BST were associated with lower risk of IADL disability independent of MVPA and that the association for ST was independent of BST and vice versa. These findings suggest not only total ST but also the manner in which it is accumulated may contribute to the maintenance of functional independence in older adults.

Screening for frailty phenotype with objectively-measured physical activity in a west Japanese suburban community: evidence from the Sasaguri Genkimon Study.

BACKGROUND: The low physical activity domain of the frailty phenotype has been assessed with various self-reported questionnaires, which are prone to possible recall bias and a lack of diagnostic accuracy. The primary purpose of this study was to define the low physical activity domain of the frailty phenotype using accelerometer-based measurement and to evaluate the internal construct validity among older community-dwellers. Secondly, we examined potential correlates of frailty in this population. METHODS: We conducted a cross-sectional study of 1,527 community-dwelling older men and women aged 65 and over. Data were drawn from the baseline survey of the Sasaguri Genkimon Study, a cohort study carried out in a west Japanese suburban community. Frailty phenotypes were defined by the following five components: unintentional weight loss, low grip strength, exhaustion, slow gait speed, and low physical activity. Of these criteria, physical activity was objectively measured with a tri-axial accelerometer. To confirm our measure's internal validity, we performed a latent class analysis (LCA) to assess whether the five components could aggregate statistically into a syndrome. We examined the correlates of frailty using multiple stepwise logistic regression models. RESULTS: The estimated prevalence of frailty was 9.3% (95% confidence intervals, CI, 8.4-11.2); 43.9% were pre-frail (95% CI, 41.5-46.4). The percentage of low physical activity was 19.5%. Objectively-assessed physical activity and other components aggregated statistically into a syndrome. Overall, increased age, poorer self-perceived health, depressive and anxiety symptoms, not consuming alcohol, no engagement in social activities, and cognitive impairment were associated with increased odds of frailty status, independent of co-morbidities. CONCLUSIONS: This study confirmed the internal construct validity of the frailty phenotype that defined the low energy expenditure domain with the objective measurement of physical activity. Accelerometry may potentially standardize the measurement of low physical activity and improve the diagnostic accuracy of the frailty phenotype criteria in primary care setting. The potential role of factors associated with frailty merits further studies to explore their clinical application.