Associations between cumulative risk, childhood sleep duration, and body mass index across childhood.

Background: Although associations between cumulative risk, sleep, and overweight/obesity have been demonstrated, few studies have examined relationships between these constructs longitudinally across childhood. This study investigated how cumulative risk and sleep duration are related to current and later child overweight/obesity in families across the United States sampled for high sociodemographic risk.

Methods: We conducted secondary analyses on 3690 families with recorded child height and weight within the Fragile Families and Child Well-Being Study. A cumulative risk composite (using nine variables indicating household/environmental, family, and sociodemographic risk) was calculated for each participant from ages 3-9 years. Path analyses were used to investigate associations between cumulative risk, parent-reported child sleep duration, and z-scored child body mass index (BMI) percentile at ages 3 through 9.

Results: Higher cumulative risk experienced at age 5 was associated with shorter sleep duration at year 9, b = - 0.35, p = .01, 95% CI [- 0.57, - 0.11]. At 5 years, longer sleep duration was associated with lower BMI, b = - 0.03, p = .03, 95% CI [- 0.06, - 0.01]. Higher cumulative risk at 9 years, b = - 0.34, p = .02, 95% CI [- 0.57, - 0.10], was concurrently associated with shorter sleep duration. Findings additionally differed by child sex, such that only male children showed an association between sleep duration and BMI.

Conclusions: Results partially supported hypothesized associations between child sleep duration, cumulative risk, and BMI emerging across childhood within a large, primarily low socioeconomic status sample. Findings suggest that reducing cumulative risk for families experiencing low income may support longer child sleep duration. Additionally, child sleep duration and BMI are concurrently related in early childhood for male children.