Prospective data on sleep complaints and associated risk factors in an older cohort

The purpose of this study is to provide data on the prevalence of insomnia and hypersomnia among older persons, the stability of these sleep complaints over time, and factors associated with disturbed sleep, in particular age.

Data on symptoms of insomnia and hypersomnia were examined for the 1994 to 1995 cohort of the Alameda County Study. In addition to age, the effects of gender, education, marital status, chronic medical conditions, functional impairment, life events, financial strain, and mood disturbance were examined using multiple logistic analyses.

Prevalence in 1994 was 23.4% for insomnia and 6.8% for hypersomnia. There was moderate concordance between sleep complaints in 1994 and 1995 (kappa=.43). There was a tendency for insomnia and hypersomnia to increase with age in 1995, but not in 1994. Only gender, mood disturbance, and chronic health problems predicted insomnia. Life events, mood disturbance, and chronic conditions predicted hypersomnia. Age, net of the effects of other factors, was not associated with risk of either insomnia or hypersomnia.

The results contribute to the expanding body of evidence concerning the important roles of psychological and somatic dysfunction in sleep disturbance. Age in and of itself is not a risk factor for insomnia or hypersomnia. That is, after adjustment for an array of putative risk factors for sleep problems, it seems the association between sleep difficulties and age is primarily due to depressed mood and physical health problems.