Chronic sleep curtailment and adiposity

Abstract

Objectives: To examine the extent to which chronic sleep curtailment from infancy to mid-childhood is associated with total and central adiposity.

Methods: We studied 1046 children participating in a prospective cohort study. At age 6 months and yearly from age 1 to 7 years, mothers reported their children's sleep duration in a usual 24-hour period. The main exposure was a sleep curtailment score from age 6 months to 7 years. The range of the total score was 0 to 13, where 0 indicated the maximal sleep curtailment and 13 indicated never having curtailed sleep. Outcomes in mid-childhood were BMI z score, dual X-ray absorptiometry total and trunk fat mass index (kg/m(2)), and waist and hip circumferences (cm).

Results: The mean (SD) sleep score was 10.2 (2.7); 4.4% scored a 0 to 4, indicating multiple exposures to sleep curtailment between age 6 months to 7 years, 12.3% scored 5 to 7, 14.1% scored 8 to 9, 28.8% scored 10 to 11, and 40.3% scored 12 to 13. In multivariable models, children who had a sleep score of 0 to 4 had a BMI z score that was 0.48 U (95% confidence interval, 0.13 to 0.83) higher than those who had a sleep score of 12 to 13. We observed similar associations of higher total and trunk fat mass index and waist and hip circumferences, and higher odds of obesity (odds ratio, 2.62; 95% confidence interval, 0.99 to 6.97) among children who had a score of 0 to 4 vs 12 to 13.

Conclusions: Chronic sleep curtailment from infancy to school age was associated with higher overall and central adiposity in mid-childhood.

Keywords: BMI; adiposity; early childhood; fat mass index; obesity; sleep curtailment.

FIGURE 1

Multivariable adjusted associations of the sleep curtailment score with BMI z score at mid-childhood. The range of the total sleep score is 0 to 13, where 0 indicates the maximal sleep curtailment and 13 indicates never having curtailed sleep. Models are adjusted for maternal age, education, BMI, and parity; household income; child race/ethnicity; and child television-viewing at mid-childhood.

FIGURE 2

Multivariable adjusted associations of sleep curtailment at each age period with BMI z score at mid-childhood. Models of curtailed sleep in the later age periods are adjusted for curtailed sleep in earlier age periods. The models of curtailed sleep from age 3 to 4 years were adjusted for sleep duration from age 6 months to 2 years; models of curtailed sleep from age 5 to 7 years were adjusted for curtailed sleep from age 6 months to 2 years and 3 to 4 years, as well as for maternal age, education, BMI, and parity; household income; and child race/ethnicity.