Insomnia symptoms, sleep duration, and disability pensions: a prospective study of Swedish workers.

BACKGROUND Previous studies have found insomnia and long sleep duration to be independently associated with subsequent disability pension (DP). However, the issue of a possible gender-based pattern in this context has received little attention. PURPOSE This study aims to assess the impact of insomnia symptoms and sleep duration on the DP rates among Swedish women and men during a 12-year follow-up period. METHOD The participants, from the general population of Malmö, Sweden, were enrolled from 1992 to 1994 (n = 4,319; participation rate 41 %), aged 45-64, healthy, and employed ≥30 h per week. Baseline inquiry data concerning psychosocial circumstances and self-reported sleep habits were compared with official register-based DP rates. RESULTS Five hundred and nine persons were granted a DP. Insomnia symptoms, affirmed by 33 % of the men and 41 % of the women, were associated with receiving a DP; the hazard ratios in the fully adjusted model were 1.4 for both men [95 % confidence interval (CI) 1.1, 1.9] and women (95 % CI 1.1, 1.7). The fully adjusted hazard ratio for women sleeping ≥9 h was 7.8 (95 % CI 3.7, 16.6) for DP due to a mental disorder. In the age-adjusted analyses, the sub-domain "difficulties falling asleep" was related to DP due to mental disorders in men and DP due to cardiovascular diseases in women. CONCLUSION The findings suggest that preventing and treating insomnia symptoms could reduce DP and that disease mechanisms linking sleep disturbances to DP may differ by gender.