The temporal relationship between parental concern of overeating and childhood obesity considering genetic susceptibility: longitudinal results from the IDEFICS/I.Family study.

Background: Many genes and molecular pathways are associated with obesity, but the mechanisms from genes toobesity are less well known. Eating behaviors represent a plausible pathway, but because the relationships of eatingbehaviors and obesity may be bi-directional, it remains challenging to resolve the underlying pathways. A longitudinalapproach is needed to assess the contribution of genetic risk during the development of obesity in childhood.In this study we aim to examine the relationships between the polygenic risk score for body mass index (PRS-BMI),parental concern of overeating and obesity indices during childhood.Methods: The IDEFICS/I.Family study is a school-based multicenter pan-European cohort of children observed for6 years (mean ± SD follow-up 5.8 ± 0.4). Children examined in 2007/2008 (wave 1) (mean ± SD age: 4.4 ± 1.1, range:2-9 years), in 2009/2010 (wave 2) and in 2013/2014 (wave 3) were included. A total of 5112 children (49% girls) participatedat waves 1, 2 and 3. For 2656 children with genome-wide data we constructed a PRS based on 2.1 million singlenucleotide polymorphisms. Z-score BMI and z-score waist circumference (WC) were assessed and eating behaviorsand relevant confounders were reported by parents via questionnaires. Parental concern of overeating was derivedfrom principal component analyses from an eating behavior questionnaire.Results: In cross-lagged models, the prospective associations between z-score obesity indices and parental concernof overeating were bi-directional. In mediation models, the association between the PRS-BMI and parental concern ofovereating at wave 3 was mediated by baseline z-BMI (? = 0.16, 95% CI: 0.10, 0.21) and baseline z-WC (? = 0.17, 95%CI: 0.11, 0.23). To a lesser extent, baseline parental concern of overeating also mediated the association between thePRS-BMI and z-BMI at wave 3 (? = 0.10, 95% CI: 0.07, 0.13) and z-WC at wave 3 (? = 0.09, 95% CI: 0.07, 0.12).Conclusions: The findings suggest that the prospective associations between obesity indices and parental concernof overeating are likely bi-directional, but obesity indices have a stronger association with future parental concern ofovereating than vice versa. The findings suggest parental concern of overeating as a possible mediator in the geneticsusceptibility to obesity and further highlight that other pathways are also involved. A better understanding of thegenetic pathways that lead to childhood obesity can help to prevent weight gain.