Can sleep disturbance influence changes in mental health status? Longitudinal research evidence from ageing studies in England and Japan.

BACKGROUND

Little is known about the role of sleep disturbance in relation to changes in depressive states. We used data obtained from the participants aged 65 and over in the English Longitudinal Study of Ageing (ELSA, waves four and five, N = 3108) and the Japan Gerontological Evaluation Study (JAGES, 2010 and 2013 sweeps, N = 7527) to examine whether sleep disturbance is longitudinally associated with older adults' patterns of depressive states.

METHODS

We created four patterns of depressive states (non-case, recovered, onset, repeatedly depressive) by combining responses to the measures (scoring four or more on seven items from the Center for Epidemiological Studies Depression Scale for the ELSA participants and scoring five or more for the Geriatric Depression Scale-15 for the JAGES participants) obtained at the baseline and follow-up. Sleep disturbance was assessed through responses to three questions on sleep problems. Age, sex, partnership status, household equivalised income, alcohol and cigarette use, and physical function were treated as confounders in this study. Additionally, information on sleep medication was available in JAGES and was included in the statistical models.

RESULTS

More ELSA participants were non-depressive cases and reported no sleep disturbances compared with the JAGES participants. Findings from multinomial logistic regression analysis showed that more sleep disturbance was associated with the onset group in ELSA (RRR = 2.37, 95% CI = 1.44-3.90) and JAGES (RRR = 2.41, 95% CI = 1.79-3.25) as well as the recovery (RRR = 3.42, 95% CI = 1.98-5.90, RRR = 2.71, 95% CI = 1.95-3.75) and repeatedly depressed group (RRR = 7.24, 95% CI = 3.91-13.40, RRR = 5.16, 95% CI = 3.82-6.98).

CONCLUSIONS

Findings suggest that the association between sleep disturbance and depression in older adults is complex.