Sleep disturbance and its correlates among elderly Japanese.

Although sleep disturbance is a major public health problem in the elderly, few studies have examined the association between sleep disturbance and other related factors in Japan. We examined correlates of sleep disturbance among Japanese elderly. Participants in this cross-sectional study (255 men and 263 women) were those enrolled in a population-based health examination for 65 year-old residents in N City, Japan in 1996 and 1997. Epidemiological data were collected by a self-administered questionnaire. Sleep disturbances were assessed by three common symptoms: difficulty in falling asleep, frequent awakening at night and not feeling rested in the morning. The mean sleep duration was longer in men than in women (7.2 vs 6.8 h, P<0.01), and women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, P<0.05). Sleep disturbances were associated with low educational attainment, retirement from work, higher body mass index (BMI), irregular bedtime, history of cardiovascular disease, arthritis or joint pain and prostatic hypertrophy, and lower subjective well-being in men, and the use of sleeping pills and depression in both genders, but not with marital status, residential status, smoking habits, exercise, limited instrumental activity of daily living, and past episode of such chronic diseases as hypertension and stroke. Our study suggests a close association of sleep disturbances among elderly Japanese with several medical/psychiatric health problems that are usually more prevalent in such an age group. Our findings emphasize the realistic need for clinicians to take underlying health problems into consideration when their patients complain of sleep-related symptoms.