Trajectories of Short Sleep Based on Ethnicity, Gender

Early intervention is likely needed to prevent short sleep duration during adulthood, according to study results published in the American Journal of Epidemiology.

Researchers from Emory University sourced data from the National Longitudinal Study of Adolescent to Adult Health, which recruited participants from 80 high schools and 52 middle schools in the United States between 1994 and 1995. Participants (N=12,593) underwent in-home interviews at baseline, in 1996, from 2001 to 2002, in 2008, and from 2016 and 2018, respectively. Trajectories of self-reported sleep duration were evaluated on the basis of gender and ethnicity. Long sleep was defined as more than 12 hours at 6 to 12 years of age, more than 10 hours at 13 to 18 years of age, and more than 9 hours at over 18 years of age, respectively.

Participants had a mean age of 13.4 years at baseline and 38.2 years at the final follow-up. The study population comprised 3831 White men, 3236 White women, 1573 Black men, 1525 Black women, 1302 Hispanic men, and 1126 Hispanic women, respectively.

The average sleep duration was 8.1 (SD, 1.1) hours at 13.4 years of age, 7.4 (SD, 1.2) hours at 16.7 years of age, 7.3 (SD, 1.0) hours at 22.1 years of age, 7.2 (SD, 1.0) hours at 28.7 years of age, and 6.6 (SD, 1.1) hours at 38.2 years of age, respectively.

Black girls reported the shortest sleep duration (mean, 7.8 hours) and White boys reported the longest sleep duration (mean, 8.3 hours) at baseline. At the final follow-up, Black men reported the shortest sleep duration (mean, 6.3 hours) and White women reported the longest (mean, 6.7 hours) sleep duration.

Three trajectories of sleep duration were observed: consistent increasing short sleepers (67.3%), late onset short sleepers (20.2%), and early onset short sleepers (12.5%). Hispanic men were more likely to be early onset short sleepers, Black men were more likely to be consistent increasing short sleepers, and White women were more likely to be late onset short sleepers.

The major limitation of this study is the reliance of self-reported sleep duration.

Study authors concluded, “Our findings underscore the need to examine sleep within an intersectionality framework to advance sleep disparities research. The consequences of examining a single social identity may result in inaccurate documentation of sleep disparities and subsequently ineffective strategies to reduce these disparities. The findings further suggest that intervening as early as adolescence to prevent short sleep in adulthood would be particularly important given that a high proportion of the sample had an increasing likelihood of short sleep duration from early adolescence to adulthood.”