Association between sleep duration from midlife and the risk of physical frailty in late life

Sleep duration has been contemporaneously associated with physical frailty, but their prospective association remains unclear. In this study, we used data from 10,792 participants in the Singapore Chinese Health Study who were followed up over 20 years. Sleep durations were recorded at baseline (mean age: 52y), second follow-up (mean age: 64y) and third follow-up (mean age: 72y). Physical frailty was assessed using a modified frailty phenotype at the third follow-up. Compared to 7h/day, short sleep durations of ≤5h/day at baseline and second follow-up were associated with increased likelihood of physical frailty [ORs (95% CIs): 1.43 (1.14-1.79) and 1.29 (1.04-1.60)]. Long sleep durations of ≥9h/day at baseline and second follow-up were also associated with increased likelihood of physical frailty [ORs (95% CIs): 1.62 (1.26-2.08) and 1.27 (1.06-1.53)]. Compared to those who maintained 6-8h/day of sleep at both time-points, baseline short sleepers who prolonged their sleep by ≥2h at second follow-up, as well as baseline long sleepers who shortened their sleep by ≥2h at second follow-up, still had increased likelihood of physical frailty at third follow-up. In this cohort, both short and long sleep durations at midlife, irrespective of changes thereafter, were associated with increased likelihood of physical frailty in late life.