Risk Factors for Obesity: Further Evidence for Stronger Effects on Overweight Children and Adolescents Compared to Normal-Weight Subjects

Andreas Beyerlein,Rüdiger Von Kries,André M Toschke,Angelika Schaffrath Rosario

doi:10.1371/journal.pone.0015739

Andreas Beyerlein, Rüdiger Von Kries + Show 2 more

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https://doi.org/10.1371/journal.pone.0015739

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Abstract

BackgroundWe recently showed that in preschoolers risk factors for overweight show stronger associations with BMI in children with high BMI values. However, it is unclear whether these findings might also pertain to adolescents.MethodsWe extracted data on 3–10 year-old (n = 7,237) and 11–17 year-old (n = 5,986) children from a representative cross-sectional German health survey (KiGGS) conducted between 2003 and 2006 and calculated quantile regression models for each age group. We used z-scores of children's body mass index (BMI) as outcome variable and maternal BMI, maternal smoking in pregnancy, low parental socioeconomic status, exclusive formula-feeding and high TV viewing time as explanatory variables.ResultsIn both age groups, the estimated effects of all risk factors except formula-feeding on BMI z-score were greatest for children with the highest BMI z-score. The median BMI z-score of 11–17 year-old children with high TV viewing time, for example, was 0.11 [95% CI: 0.03, 0.19] units higher than the median BMI z-score of teenage children with low TV viewing time. This risk factor was associated with an average difference of 0.18 [0.06, 0.30] units at the 90th percentile of BMI z-score and of 0.20 [0.07, 0.33] units at the 97th percentile.ConclusionsWe confirmed that risk factors for childhood overweight are associated with greater shifts in the upper parts of the children's BMI distribution than in the middle and lower parts. These findings pertain also to teenagers and might possibly help to explain the secular shift in the upper BMI percentiles in children and adolescents.

Highlights

All over the world, increasing prevalences of childhood overweight have been reported [1,2,3] which appear to be based mainly on a shift of the upper parts of the body mass index (BMI) distribution rather than a shift of the BMI in the whole population [4,5].In a previous study using data from the Bavarian school entry examinations [6], we observed that risk factors for overweight are associated with stronger effects on higher BMI percentiles than on average BMI values, suggesting that incremental exposure to those risk factors would primarily result in more extreme values of BMI or body weight
The mean BMI z-score was almost equal in 3–10 and 11–17 year old children, children from the teenage group were more likely (p,0.05) to be exposed to high maternal BMI or exclusive formula-feeding and less likely to have been exposed to maternal smoking in pregnancy compared to the younger children in the dataset
The adjusted quantile regression coefficients were positive for almost any BMI z-score percentile, with significant (p,0.05) associations for all percentiles at or above the median, except for exclusive formulafeeding and low parental Socioeconomic status (SES)

Summary

Introduction

In a previous study using data from the Bavarian school entry examinations [6], we observed that risk factors for overweight are associated with stronger effects on higher BMI percentiles than on average BMI values, suggesting that incremental exposure to those risk factors would primarily result in more extreme values of BMI or body weight. We recently showed that in preschoolers risk factors for overweight show stronger associations with BMI in children with high BMI values It is unclear whether these findings might pertain to adolescents

Methods

Results

Conclusion