Purpose: Little is known about population determinants of short sleep duration. The authors examined associations between short sleep duration and income, education and race/ethnicity, and assessed changes over time in relative disparities.
Methods: Questionnaire data from the Alameda County Health and Ways of Living Study (ACS) was obtained at five time-points (1965, 1974, 1983, 1994, and 1999) for short sleep duration (<7 hours sleep per night). Household income, education level, and race/ethnicity were assessed at baseline (n = 6,928). Odds ratios were computed to examine short sleep duration across income, education and race/ethnicity, adjusting for age, sex and time-varying covariates, and to assess changes over time.
Results: Prevalence of short sleep at baseline was 15.2%. The (age-adjusted) odds of short sleep was increased for the lowest household income quintile (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.34-1.94), those with less than high school education (OR, 1.51; 95% CI, 1.30-1.75), and among African Americans (OR, 1.97; 95% CI, 1.68-2.30). Relative disparities increased over time for African-American and Hispanic, compared with white, participants.
Conclusions: Socioeconomic position is a robust determinant of short sleep duration, even after adjusting for health-related characteristics linked to short sleep duration.