Insomnia with short sleep duration and mortality: the Penn State cohort

Abstract

Study objectives: Because insomnia with objective short sleep duration is associated with increased morbidity, we examined the effects of this insomnia subtype on all-cause mortality.

Design: Longitudinal.

Setting: Sleep laboratory.

Participants: 1,741 men and women randomly selected from Central Pennsylvania.

Measurements: Participants were studied in the sleep laboratory and were followed-up for 14 years (men) and 10 years (women). "Insomnia" was defined by a complaint of insomnia with duration > or = 1 year. "Normal sleeping" was defined as absence of insomnia. Polysomnographic sleep duration was classified into two categories: the "normal sleep duration group" subjects who slept > or = 6 h and the "short sleep duration group" subjects who slept < 6 h. We adjusted for age, race, education, body mass index, smoking, alcohol, depression, sleep disordered breathing, and sampling weight.

Results: The mortality rate was 21% for men and 5% for women. In men, mortality risk was significantly increased in insomniacs who slept less than 6 hours compared to the "normal sleep duration, no insomnia" group, (OR = 4.00, CI 1.14-13.99) after adjusting for diabetes, hypertension, and other confounders. Furthermore, there was a marginally significant trend (P = 0.15) towards higher mortality risk from insomnia and short sleep in patients with diabetes or hypertension (OR = 7.17, 95% CI 1.41-36.62) than in those without these comorbid conditions (OR = 1.45, 95% CI 0.13-16.14). In women, mortality was not associated with insomnia and short sleep duration.

Conclusions: Insomnia with objective short sleep duration in men is associated with increased mortality, a risk that has been underestimated.