Subjective insomnia is associated with low sleep efficiency and fatigue in middle-aged women

Abstract

Objectives: Many middle-aged women are affected by sleep disturbance. We investigated how subjective insomnia is associated with objective sleep parameters and other background characteristics.

Methods: This cross-sectional study used baseline data obtained from 95 women aged 40–59 years who participated in another study assessing the effects of a dietary supplement. Participants wore an actigraph unit for 3 days to collect information concerning physical activities and objective sleep parameters and were then evaluated for body composition, cardiovascular parameters, and menopausal symptoms including insomnia and fatigue, and lifestyle factors. Stratifying Athens Insomnia Scale scores as low (0–5 points, control group) and high (≥ 6 points, subjective insomnia group), we sought to identify the parameters that are independently associated with subjective insomnia.

Results: Women with subjective insomnia (n = 30) had lower sleep efficiency than did the controls. They were also older; had more live births, lower height, higher body mass index, lower ankle brachial index, and more severe menopausal symptoms including fatigue; took more naps; smoked more cigarettes; and more of them were full-time workers. Multivariate logistic regression analysis revealed that low sleep efficiency (adjusted odds ratio, 1.44 per 1% decrease in sleep efficiency; 95% confidence interval 1.06–2.05) and fatigue assessed with Brief Fatigue Inventory (BFI) (adjusted odds ratio, 1.57 per 1-point increase in BFI score; 95% confidence interval 1.19–2.13) were independent contributors to subjective insomnia.

Conclusions: Low sleep efficiency and feeling of fatigue were found to be independently associated with subjective insomnia in middle-aged women.

Keywords:

• Sleep disorder
• actigraphy
• menopause
• menopausal symptoms

Conflict of interest

The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper.

Source of funding

M.T. received an unrestricted research grant from Kikkoman Corporation.