Teenagers Increasingly Sleep-Deprived

Janis C. Kelly

February 16, 2015

US adolescents became progressively more sleep-deprived after 1990, researchers report in an article published online February 16 in Pediatrics. Girls were more likely to be affected than boys, as were racial/ethnic minorities, city dwellers, and those from poor families. Teenagers from racial/ethnic minorities and from poor families were likely to think they were getting enough sleep even when they were not.

Katherine M. Keyes, PhD, assistant professor of epidemiology at Columbia University's Mailman School of Public Health in New York City, and colleagues analyzed data from 1991 through 2012 on 272,077 adolescents from Monitoring the Future, a nationally representative cross-sectional survey of adolescent birth cohorts. Participants were asked how often they got at least 7 hours of sleep per night, and how often they got less sleep than they should. The National Sleep Foundation recommends 9 hours of sleep per night for adolescents.

The researchers report that sleep consistently decreased for all age groups in all periods, with the exception of the relatively small number of 19-year-olds included in this high school sample. The largest sleep decreases occurred between 1991 to 1995 and 1996 to 2000. Fifteen-year-olds were hit hardest, with adequate sleep dropping from 71.5% in 1991 to 63.0% in 2012.

"There was consistent evidence of a period effect whereby sleep was decreasing regardless of age in more recent years for all subgroups, and some evidence of a positive cohort effect (ie, increase) for those born in the early 1990s, but only for self-perceived adequate sleep and only in some subgroups," the authors write.

Girls were less likely than boys at all time periods to report adequate sleep, with odds ratios of 0.68 in 1996 to 2000 and 0.66 in 2011 to 2012.

Black and Hispanic adolescents were increasingly less likely than white adolescents to report sleeping at least 7 hours per night, and this disparity increased in more recent periods. "[R]acial/ethnic minorities and adolescents in lower [socioeconomic] strata are simultaneously less likely to get ≥7 hours of sleep per night but more likely to report regularly getting adequate sleep; these findings suggest a mismatch exists between actual sleep and perceptions of adequate sleep," the authors write.

Among the possible contributing factors might be "racial and socioeconomic differences in attitudes toward sleep, sleep patterns within families, and social activities at night that interfere with sleep, suggesting that cultural norms regarding sleep adequacy may in part underlie the mismatch between actual self-reported hours of sleep and self-reported adequacy of sleep," the authors suggest.

The hope that a school-based sleep education program for adolescents might mitigate some of these problems was largely dashed by randomized trial data from Yun Kwok Wing, FRCPsych, and colleagues from the Chinese University of Hong Kong SAR, China, published online February 16 in Pediatrics. In findings unlikely to surprise parents of teenagers, the researchers observed that the education program increased the students' textbook knowledge about sleep but did not change how much they slept.

Dr Wing and colleagues write, "Even when they realized the importance of sleep, the subjects' propensity to change was low given the highly packed daily life schedule among this age group."

Students randomly assigned to the intervention (seminar, workshops, slogan competition, brochure, educational website) had reduced consumption of caffeine-containing energy drinks by about half and improved on some measure of mental health status compared with those assigned to the "no intervention" group. There was no placebo control.

Dr Keyes and coauthors have disclosed no relevant financial relationships. Dr Wing has received sponsorship from Lundbeck Export A/S, Servier Hong Kong Ltd, and Celki Medical Company and was a part-time paid consultant for Renascence Therapeutics Ltd. A coauthor on Dr Wing's article has received honoraria for consultancy or giving lectures from AstraZeneca, Pfizer, Sanofi, Novo Nordisk, Eli Lilly, Merck Serono, and Nestlé. The other authors have disclosed no relevant financial relationships.

Pediatrics. Published online February 16, 2015. Keyes abstract, Wing abstract


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