To test the association between sleep duration and telomere length in a pediatric population.

We analyzed cross-sectional data for 1567 children from the age 9 study wave of the Fragile Families and Child Wellbeing Study, a population-based birth cohort of children born between 1998 and 2000 in large American cities (population >200 000). We measured telomere length using quantitative polymerase chain reaction, and children's typical nightly sleep duration was reported by their primary caregivers. Using linear regression, we estimated the association between sleep duration and telomere length both in unadjusted models and adjusting for a number of covariates.

We found that children with shorter sleep durations have shorter telomeres than children with longer sleep durations. Each hour less of nightly sleep duration is associated with having telomeres that are 0.015 log-kilobases per chromosome shorter (P < .05). We found no difference in this association by race, sex, or socioeconomic status.

We provide preliminary evidence that children with shorter sleep durations have shorter telomeres. This finding is consistent with a broader literature indicating that suboptimal sleep duration is a risk for increased physiological stress and impaired health. Future research should address the limitations of our study design by using longitudinal study designs and telomere measurements, measuring sleep duration via polysomnography or actigraphy, and assessing the intermediate biological mechanisms of the link between sleep and telomere dynamics.