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Short and long daily sleep duration and hypnotic use are risk factors for dementia and death in Japanese elderly adults.

BackgroundThis study aimed to examine the associations between time spent in prolonged and non-prolonged sedentary bouts and the development of metabolic syndrome.MethodsWe 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.ResultsDuring 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.ConclusionsSedentary 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3570-3) contains supplementary material, which is available to authorized users.

BackgroundSedentary behavior has been reported to be associated with metabolic and vascular health independent of moderate-to-vigorous physical activity (MVPA). In order to select appropriate options to measure sedentary behavior in practice and research settings, it is worthwhile to characterize the extent to which objective and subjective measures of sedentary behavior quantify adverse health risks in the same population. This cross-sectional analysis compared accelerometer-derived and self-reported sedentary time to identify their association with cardio-metabolic risk factors.MethodsCross-sectional analysis was conducted using data from 661 Japanese workers (145 women) aged 20–64 years. Participants wore a tri-axial accelerometer device for 10 consecutive days and completed the Japan Atherosclerosis Longitudinal Study Physical Activity Questionnaire. Data on body mass index, waist circumference, resting blood pressure, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, total:HDL cholesterol ratio, blood glucose, and glycosylated hemoglobin (HbA1c) were obtained from annual health examinations.ResultsBoth accelerometer-derived and self-reported sedentary time were deleteriously associated with triglycerides, HDL-cholesterol, total:HDL ratio, and HbA1c after adjustment for potential confounders including MVPA. There were no significant differences in regression coefficients between the two measures. Thus, the magnitude of the associations of both measures with cardio-metabolic risk factors was similar, despite poor agreement between them. Occupational sedentary time was correlated with both measures of total sedentary time, and more consistently associated with cardio-metabolic risk factors than sedentary leisure time.ConclusionsBoth accelerometer and self-report measurements are similarly associated with cardio-metabolic risk factors in a Japanese working adult population. Subjective and objective measures of sedentary behaviors appear to capture different aspects of behaviors. Further efforts to establish data processing methods integrating objective and subjective measures are needed to more effectively assess sedentary time’s relationship to health outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2458-14-1307) contains supplementary material, which is available to authorized users.

We investigated the long-term influence of physical activity on the risk of dementia in an elderly Japanese population. A total of 803 community-dwelling elderly Japanese individuals without dementia aged ≥65 years were followed prospectively for 17 years. Physically active status was defined as engaging in exercise at least one or more times per week during leisure time, and participants were divided into an active group and an inactive group by the presence or absence of such physical activity. The risk estimates of physical activity on the development of all-cause dementia and its subtypes were computed using a Cox proportional hazards model. During the follow-up, 291 participants developed all-cause dementia. Of these, 165 had Alzheimer's disease (AD), 93 had vascular dementia (VaD), and 47 had other dementia. Compared with the inactive group, the active group showed significantly lower crude incidence of AD (21.8 vs. 14.2 per 1000 person-years, p = 0.01), but no significant differences were observed for all-cause dementia (35.6 vs. 30.5, p = 0.17), VaD (11.3 vs. 9.8, p = 049), and other dementia (4.6 vs. 7.1, p = 0.15). After adjusting for potential confounders, the relationship between physical activity and risk of AD remained significant (adjusted hazard ratio 0.59, 95% confidence interval 0.41-0.84, p = 0.003). Our findings suggest that physical activity reduces the long-term risk of dementia, especially AD, in the general Japanese population.

BackgroundEpidemiologic evidence has emerged to reveal an association of albuminuria and low estimated glomerular filtration rate (eGFR) with dementia, but the findings are inconsistent. In addition, there are limited studies addressing the association between albuminuria and Alzheimer disease (AD).Methods and ResultsA total of 1562 community‐dwelling Japanese subjects aged ≥60 years without dementia were followed up for 10 years. The outcomes were incidence of all‐cause dementia and its subtypes, namely, AD and vascular dementia (VaD). The hazard ratios for the outcomes were estimated according to urine albumin–creatinine ratio (UACR) and eGFR levels using a Cox proportional hazards model. During the follow‐up, 358 subjects developed all‐cause dementia (238 AD and 93 VaD). Higher UACR level was significantly associated with greater multivariable‐adjusted risks of all‐cause dementia (hazard ratios [95% confidence intervals]: 1.00 [reference], 1.12 [0.78–1.60], 1.65 [1.18–2.30], and 1.56 [1.11–2.19] for UACR of ≤6.9, 7.0–12.7, 12.8–29.9, and ≥30.0 mg/g, respectively), AD (1.00 [reference], 1.20 [0.77–1.86], 1.75 [1.16–2.64], and 1.58 [1.03–2.41], respectively), and VaD (1.00 [reference], 1.03 [0.46–2.29], 1.94 [0.96–3.95], and 2.19 [1.09–4.38], respectively). On the other hand, lower eGFR level was marginally associated with greater risk of VaD, but not AD. Subjects with UACR ≥12.8 mg/g and eGFR of <60 mL/min per 1.73 m2 had 3.3‐fold greater risk of VaD than those with UACR <12.8 mg/g and eGFR of ≥60 mL/min per 1.73 m2.ConclusionsAlbuminuria is a significant risk factor for the development of both AD and VaD in community‐dwelling Japanese elderly. Moreover, albuminuria and low eGFR are mutually associated with a greater risk of VaD.

Our findings suggest that handgrip strength levels in midlife and late life are inversely associated with the risks of all-cause and non-cancer death in the general Japanese population.