Poor sleep quality and functional decline in older women.

OBJECTIVES

To determine whether objectively measured sleep quality predicts 5-year incident instrumental activity of daily living (IADL) impairment and decline in grip strength and gait speed in older women.

DESIGN

Prospective cohort.

SETTING

Participants' homes, Study of Osteoporotic Fractures sites.

PARTICIPANTS

Eight hundred seventeen women with a mean age of 82.4 at baseline.

MEASUREMENTS: Participants completed 4.1 ± 0.7 nights of wrist actigraphy at baseline and measures of IADL impairment, grip strength, and gait speed at baseline and 5-year follow-up.

RESULTS

After 5 years of follow-up, approximately 41% of participants had incident impairment in one or more IADLs. The quartile of women with the shortest total sleep time (TST) had 93% greater odds of incident IADL impairment than the longest sleepers (adjusted odds ratio (AOR) = 1.93, 95% confidence interval (CI) = 1.25-2.97). Similarly, the quartile of women with the lowest sleep efficiency (SE) had 65% greater odds of impairment than those with the highest (AOR = 1.65, 95% CI = 1.06-2.57). Women in the shortest TST quartile had twice the odds of declining grip strength as those with the longest TST (AOR = 1.97, 95% CI = 1.17-3.32). Finally, women in the quartiles with the most wake after sleep onset (WASO) and the lowest SE had approximately 90% greater odds of grip strength decline than those with the least WASO (AOR = 1.90, 95% CI = 1.11-3.24) and SE (AOR = 1.92, 95% CI = 1.12-3.29).

CONCLUSION

Findings indicate that shorter sleep duration, greater WASO, and lower SE are risk factors for functional or physical decline in older women.