Abstract
Introduction:
Infant sleep problems have been defined using a variety of definitions. No study has assessed the association between infant sleep problems and childhood overweight or obesity using different definitions of sleep problems.
Hypothesis:
We assessed the hypothesis that the effect of infant sleep problems on childhood overweight or obesity would differ based on the definition of sleep problems used.
Methods:
In the multi-site study of Early Child Care and Youth Development of the National Institute of Child Health and Human Development, sleep problems were assessed using Lozoff and colleagues (night waking occurring more than 3 times per week accompanied by parental report of disturbance), Richman and colleagues (waking 5 or more nights per week for the past 3 months in addition to one of the following: co-sleeping with parents, waking 3 or more times per night, or waking event lasting at least 20 minutes), and Zuckerman and colleagues (waking 3 or more times per night, waking event lasting at least 1 hour, or parental report of severe disturbance) definitions. Infants (<24 months of age) with sleep problems (ever versus never) were included in this analysis. Childhood weight status (normal: BMI 5th-< 85th percentile; being overweight: BMI 85th-<95th percentile; or being obese: BMI ≥95th percentile) was defined according to 2000 Centers for Disease Control and Prevention cut-offs (N=895). Multinomial logistic regression was used to examine the association between sleep problems during infancy and the odds of childhood overweight or obesity at grade 6 after adjusting for birth weight, race, sex, breastfeeding, maternal poverty, family structure, and maternal education.
Results:
The prevalence of childhood overweight and obesity at grade 6 was 15.6% and 19.0%, respectively. The prevalence of having sleep problems during infancy was 24.9% (Zuckerman definition), 12.6% (Richman definition), and 20.6% (Lozoff definition), per different definitions used. Infants with history of having sleep problems were found more likely to be overweight at grade 6 using either Zukerman’s (Odds ratio (OR) = 1.68; 95% Confidence interval (CI) = 1.11-2.55) or Richman’s definition (OR = 1.76; 95% CI = 1.05-2.97), but not using Lozoff’s definition of sleep problems.
Conclusion:
Infant sleep problems increased the odds of childhood overweight (but not obesity) at grade 6. However, the observed associations varied according to the definition of sleep problems used. More research is needed to construct a single definition of infant sleep problems in order to more accurately predict overweight or obesity later in life.