Poster #106 - Links Between Physical Activity and Adiposity Across the Transition from Infancy to Early Childhood

• In Event: 2-110 - Poster Session 07
  In Poster Session: PS 07 Section - Health, Growth, Injury

Integrative Statement

Toddlers who are overweight are at risk of remaining so as they age, thereby highlighting the importance of identifying potential targets of intervention in early childhood. The National Academies of Science Committee on Obesity Prevention Policies for Young Children has identified physical activity (PA) as a key factor that can influence risk for obesity in early childhood. However, although there is some evidence that PA has preventative effects in older children, this has not been explored in early childhood. The present study examined the within and across-age associations between PA and tri-ponderal mass index (TMI), a measure of body fatness, in toddlers at ages 2 and 3 years.

Procedure:
The sample 627 children (Nmales=331, Nfemales=296) assessed within 2 weeks of their 2nd and 3rd birthdays. At each age, actigraphs were attached one per limb and worn in the home for 48-hours. A daytime PA measure was formed by averaging activity counts across the 4 limbs for the hours between 7 am and 9 pm. Children were weighed in light indoor clothing and stocking feet. Height was measured using a stadiometer. TMI was computed as weight in kilograms divided by height in meters cubed. Cross-lagged panel models were fit to the data using Mplus. Covariates included sex on both PA and TMI and season of assessment on PA.

Results:
The cross-lagged model (Figure 1) provided a good fit to the data (X2= 4.44, df=6, p=.61; RMSEA=.00, CI:.00-.044; CFI=1.0). Sex was a significant covariate indicating that males were more active and had more body fat than females at age 2. There was also a seasonal effect on activity. Above and beyond these effects, PA and TMI were stable across age and were negatively correlated within each age, rAge2=-.13 (-.22;-.04); rAge3=-.12 (-.22;-.01). The cross-lagged effect for TMI at age 2 predicting PA at age 3 was significant, but the reciprocal effect for PA at age 2 predicting later TMI was not. The covariance between novel effects on PA and TMI at age 3 was nonsignificant, indicating that the negative correlation between PA and TMI at this latter age is largely due to effects that were transmitted from age 2.

Conclusion:
Physical activity and adiposity are negatively associated in early childhood, however, the current study suggests the direction of effects is from early adiposity impacting later levels of physical activity. While these results do not support the notion of habitual physical activity as a protective factor for risk of being overweight in toddlerhood, given that early physical activity is associated with motor development and that childhood physical activity levels track to adulthood, it may be that early adiposity is a risk factor for nonoptimal physical fitness.

Authors

• Kimberly Saudino, Boston University
  Presenting Author

• Jody Ganiban, George Washington University
  Non-Presenting Author