Parental perception of child's weight status and subsequent BMIz change: the KOALA birth cohort study

Background: Parents often fail to correctly perceive their children's weight status, but no studies have examined the association between parental weight status perception and longitudinal BMIz change (BMI standardized to a reference population) at various ages. We investigated whether parents are able to accurately perceive their child's weight status at age 5. We also investigated predictors of accurate weight status perception. Finally, we investigated the predictive value of accurate weight status perception in explaining children's longitudinal weight development up to the age of 9, in children who were overweight at the age of 5. Methods: We used longitudinal data from the KOALA Birth Cohort Study. At the child's age of 5 years, parents filled out a questionnaire regarding child and parent characteristics and their perception of their child's weight status. We calculated the children's actual weight status from parental reports of weight and height at ages 2, 5, 6, 7, 8, and 9 years. Regression analyses were used to identify factors predicting which parents accurately perceived their child's weight status. Finally, regression analyses were used to predict subsequent longitudinal BMIz change in overweight children. Results: Eighty-five percent of the parents of overweight children underestimated their child's weight status at age 5. The child's BMIz at age 2 and 5 were significant positive predictors of accurate weight status perception (vs. underestimation) in normal weight and overweight children. Accurate weight status perception was a predictor of higher future BMI in overweight children, corrected for actual BMI at baseline. Conclusions: Children of parents who accurately perceived their child's weight status had a higher BMI over time, probably making it easier for parents to correctly perceive their child's overweight. Parental awareness of the child's overweight as such may not be sufficient for subsequent weight management by the parents, implying that parents who recognize their child's overweight may not be able or willing to adequately manage the overweight.