Normal sleep in African-Americans and Caucasian-Americans: A meta-analysis

Objective: This meta-analysis was designed to estimate the average magnitude of ethnic differences between African-Americans and Caucasian-Americans in normal sleep and to identify moderators of these differences. Methods: Included studies had to have (1) sufficient information to estimate the difference between African-Americans and Caucasian-Americans on measures of subjective or objective sleep, (2) adult samples, and (3) samples of normal sleepers. Fourteen studies representing 1010 African-Americans and 3156 Caucasian-Americans aged 18. years and older met these criteria. Results: Significant ethnic differences were found, with mean effect sizes ranging from -.23 to .57. African-Americans had poorer sleep continuity and duration, less slow wave sleep, and a greater proportion of stage 2 sleep. Differences in sleep continuity and duration variables were moderated by several biopsychosocial factors, whereas sleep architecture differences were not influenced by any examined moderating factor. Conclusions: African-Americans slept worse objectively and subjectively than Caucasian-Americans. Sleep continuity and duration were moderated by biopsychosocial factors whereas sleep architecture was not. Implications and future research are discussed.