Objectives: To investigate factors associated with incidence and persistence of sleep complaints in an older population, with particular focus on the role of depression, subclinical depression and physical health status as predictors.
Method: An analysis was carried out of data from the Gospel Oak Study: a community survey of 656 residents within a geographic catchment area in north London, aged 65 and over who were followed up after 1 year. Subjective sleep complaint was ascertained using a single question at baseline and follow-up. Independent variables included age, sex, marital status, social class, number of physical illnesses, disability, social support deficit and depression (according to SHORT-CARE: both a categorical measure and a scale based score).
Results: Baseline prevalence of sleep complaint was 44.7%. Incidence after 1 year was 21.4%, and persistence was 66.3%. After adjustment, female sex and depression predicted incidence of sleep complaint whereas only depression caseness predicted persistence of complaint. The population attributable fractions of depression caseness for incidence and persistence of sleep complaint were 37.4 and 23.4%, respectively. Positive but weaker associations were found between sub-case depressive symptoms and these outcomes.
Conclusions: Depression was the strongest predictor of incidence and persistence of sleep complaints in this older sample. However, overall it accounted only for a minority of instances of incident/persistent symptoms.
(c) 2009 John Wiley & Sons, Ltd.