Sleep duration and progression to sarcopenia in Japanese community-dwelling older adults: a 4 year longitudinal study

Background Identifying factors that contribute to the development of sarcopenia in older adults is a public health priority. Although several studies have examined the association between sleep duration and sarcopenia, additional evidence is needed to reveal the causality of this association, especially from a longitudinal study. The purpose of the present study was to examine whether sleep duration was associated with the progression to sarcopenia and its subcomponents among community-dwelling older adults in Japan. Methods A total of 3918 older community-dwelling people (mean age: 73.2 +/- 6.0 years, 51.8% female) included in the National Center for Geriatrics and Gerontology Study of Geriatric Syndromes were analysed. Sleep duration was assessed using a self-reported questionnaire. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of progression of sarcopenia at Wave 2 (4 years later), according to the three categories of sleep duration [short: <= 6.0 h, medium: 6.1-8.9 h (control), & long: >= 9.0 h)] at Wave 1. Results The numbers in each group in the second wave among the total sample were as follows: short 403 (10.3%), medium 2877 (73.4%), and long 638 (16.3%). Significant associations with the progression of sarcopenia were found in the long sleep duration group compared with the medium one, even after adjustment for other covariates (OR 1.66, 95% CI: 1.02-2.69, P = 0.040). Long sleep duration was significantly associated with slow gait (OR: 1.55, 95% CI: 1.17-2.06, P = 0.002) and low grip strength (OR: 1.34, 95% CI: 1.00-1.78, P = 0.047) but was not associated with low muscle mass (OR: 1.33, 95% CI: 0.74-2.38, P = 0.343). Conclusions This study revealed that long sleep duration was associated with an increased risk of progression to sarcopenia among older adults.