Elucidating pathways to pediatric obesity: a study evaluating obesity polygenic risk scores related to appetitive traits in children

BACKGROUND/OBJECTIVES

Obesity polygenic risk scores (PRS) explain substantial variation in body mass index (BMI), yet associations between PRSs and appetitive traits in children remain unclear. To better understand pathways leading to pediatric obesity, this study aimed to assess the association of obesity PRSs and appetitive traits.

SUBJECTS/METHODS

This study included 248 unrelated children aged 9-12 years. DNA from the children was genotyped (236 met quality control thresholds) and four weighted polygenic risk scores from previous studies were computed and standardized: a 97 SNP PRS, 266 SNP pediatric-specific PRS, 466 SNP adult-specific PRS, and ~2 million SNP PRS. Appetitive traits were assessed using a parent-completed Child Eating Behavior Questionnaire, which evaluated food approach/avoidance traits and a composite obesogenic appetite score. BMI was directly measured and standardized by age and sex. Three associations were evaluated with linear regression: (1) appetitive traits and BMI, (2) PRSs and BMI, and (3) PRSs and appetitive traits, the primary association of interest.

RESULTS

Expected positive associations were observed between obesogenic appetitive traits and BMI and all four PRSs and BMI. Examining the association between PRSs and appetitive traits, all PRSs except for the 466 SNP adult PRS were significantly associated with the obesogenic appetite score. Each standard deviation increase in the 266 SNP pediatric PRS was associated with an adjusted 2.1% increase in obesogenic appetite score (95% CI: 0.6%, 3.7%, p = 0.006). Significant partial mediation of the PRS-BMI association by obesogenic appetite score was found for these PRSs; for example, 21.3% of the association between the 266 SNP pediatric PRS and BMI was explained by the obesogenic appetite score.

CONCLUSIONS

Genetic obesity risk significantly predicted appetitive traits, which partially mediated the association between genetic obesity risk and BMI in children. These findings build a clearer picture of pathways leading to pediatric obesity.

Associations between behavioral self-regulation and external food cue responsiveness (EFCR) in preschool-age children and evidence of modification by parenting style

Decreased behavioral regulation is hypothesized to be a risk factor for excess weight gain among children, possibly via reduced appetite-specific regulation. Little research has specifically focused on behavioral regulation and food cue responsiveness, a conditioned precursor to eating, at a young age. This study examined the association between behavioral regulation and external food cue responsiveness among preschool-age children and explored if a more structured parenting style moderated that association. Baseline data from a prospective study on media use among preschool-age children (n = 83) in Northern New England were used. Parents reported on three domains of children's behavioral regulation (attentional focusing, inhibitory control, and emotional self-regulation), the children's external food cue responsiveness (EFCR), and their parenting styles (authoritative and permissive) via validated questionnaires. Mean age among children was 4.31 (SD 0.91) years, 57% of children were male, 89% were non-Hispanic white, and 26.2% had overweight or obesity. In a series of adjusted linear regression models, lower attentional focusing (standardized β, βs = -0.35, p = 0.001), inhibitory control (βs = -0.30, p = 0.008), and emotional self-regulation (standardized beta, βs = -0.38, p < 0.001) were each significantly associated with greater EFCR. In exploratory analyses, a more structured parenting style (more authoritative or less permissive) mitigated the associations between inhibitory control and EFCR (Bonferroni-adjusted p-interaction < 0.017). Findings support that lower attentional focusing, inhibitory control, and emotional self-regulation relate to greater ECFR in preschool-age children. The association between inhibitory control and EFCR may be modified by parenting style. Further research is needed to understand if children's responsiveness to external food cues may account for reported associations between lower behavioral regulation and adiposity gain over time.

Corrigendum: Differential neural reward reactivity in response to food advertising medium in children

[This corrects the article DOI: 10.3389/fnins.2023.1052384.].

Differential neural reward reactivity in response to food advertising medium in children

Introduction

Food cues including food advertisements (ads) activate brain regions related to motivation and reward. These responses are known to correlate with eating behaviors and future weight gain. The objective of this study was to compare brain responses to food ads by different types of ad mediums, dynamic (video) and static (images), to better understand how medium type impacts food cue response.

Methods

Children aged 9-12 years old were recruited to complete a functional magnetic resonance imaging (fMRI) paradigm that included both food and non-food dynamic and static ads. Anatomical and functional images were preprocessed using the fMRIPrep pipeline. A whole-brain analysis and a targeted region-of-interest (ROI) analysis for reward regions (nucleus accumbens, orbitofrontal cortex, amygdala, insula, hypothalamus, ventral tegmental area, substantia nigra) were conducted. Individual neural responses to dynamic and static conditions were compared using a paired t-test. Linear mixed-effects models were then constructed to test the differential response by ad condition after controlling for age, sex, BMI-z, physical activity, and % of kcal consumed of a participant's estimated energy expenditure in the pre-load prior to the MRI scan.

Results

A total of 115 children (mean=10.9 years) completed the fMRI paradigm. From the ROI analyses, the right and left hemispheres of the amygdala and insula, and the right hemisphere of the ventral tegmental area and substantia nigra showed significantly higher responses for the dynamic food ad medium after controlling for covariates and a false discovery rate correction. From the whole-brain analysis, 21 clusters showed significant differential responses between food ad medium including the precuneus, middle temporal gyrus, superior temporal gyrus, and inferior frontal gyrus, and all regions remained significant after controlling for covariates.

Discussion

Advertising medium has unique effects on neural response to food cues. Further research is needed to understand how this differential activation by ad medium ultimately affects eating behaviors and weight outcomes.

Measurement of external food cue responsiveness in preschool-age children: Preliminary evidence for the use of the external food cue responsiveness scale

BACKGROUND

Conditioned eating in response to external food cues may contribute to obesity risk in young children.

OBJECTIVES

To develop a brief, parent-reported scale to measure external food cue responsiveness for preschool-age children.

METHODS

Focus groups with parents of preschool-age children were conducted to create an initial pool of items reflecting children's behavioral responses to external food cues. Items were included in a nationally-distributed online survey of parents of preschool-age children (n = 456). Factor analysis was used to reduce the initial item pool, the scale's psychometric properties were assessed, and scores were correlated with reported snacking behaviors.

RESULTS

Nine items met inclusion criteria in the final scale, which had high internal consistency (alpha = 0.86). Final scores were the mean across the nine items. External food cue responsiveness was greater among children with, versus without, usual TV advertisement exposure. Furthermore, greater external food cue responsiveness mediated the relationship between children's usual TV advertisement exposure and snacking during TV viewing. Findings remained statistically significant when adjusted for food responsiveness as measured with the Child Eating Behavior Questionnaire.

CONCLUSIONS

Findings provide preliminary evidence that external food cue responsiveness is measurable by parental report in preschool-age children.

FTO genotype and weight status among preadolescents: Assessing the mediating effects of obesogenic appetitive traits

Polymorphisms in the Fat Mass and Obesity Associated (FTO) gene are robustly associated with overweight and obesity among children, although the underlying mechanisms are poorly understood. We tested if appetitive traits partially mediated the association between FTO genotype and increased BMI among a sample of US preadolescents. Data were from 178 unrelated 9-10 year olds who participated in an experimental study between 2013 and 2015. Children's DNA was isolated from buccal swabs, and the rs9939609 SNP in the FTO gene was genotyped. Children's age- and sex-adjusted BMI z-scores were computed using height and weight measured at the laboratory. Parents completed the Child Eating Behavior Questionnaire that includes three validated scales of habitual appetitive traits related to drive and regulation: satiety responsiveness, enjoyment of food and food responsiveness. Structural equation modeling was used to assess if those traits mediated the relationship between FTO and BMI z-score. The sample of children was 48.9% male and 91.0% non-Hispanic white. FTO distribution was in Hardy Weinberg equilibrium, and 16.3% of participants were homozygous for the high-risk allele. Mean BMI z-score was greatest among those with the high-risk genotype (ANOVA P < 0.01). In separate structural equation models adjusted for the child's sex and maternal education, decreased satiety responsiveness and increased food responsiveness each partially mediated the positive association between the high-risk genotype and increased BMI z-score (P-value for each indirect effect <0.05). Continued research is needed to better understand how other known genetic obesity risk factors may impact appetitive traits among children.

Randomized Exposure to Food Advertisements and Eating in the Absence of Hunger Among Preschoolers

BACKGROUND

Preschoolers in the United States are heavily exposed to unhealthy food advertisements. Whether such exposure promotes cued eating has not been documented in this age group.

METHODS

Randomized experiment among 60 children, aged 2 to 5 years, recruited in 2015-2016 from New Hampshire and Vermont. Children completed the experiment at a behavioral laboratory. Children were provided with a healthy snack to consume upon arrival then randomized to view a 14-minute TV program embedded with advertisements for either a food or a department store. Children were provided 2 snack foods to consume ad libitum while viewing the TV program; 1 of those snacks was the food advertised. Eating in the absence of hunger (EAH) was operationalized as the kilocalories of snack foods consumed. t tests were used to compare EAH by advertisement condition; linear regression models assessed effect modification by the child's age, sex, BMI percentile, and parental feeding restriction.

RESULTS

Mean age was 4.1 (SD 0.9) years, 55% of children were male, 80% were non-Hispanic white, and 20% were overweight or obese. There were no differences in child or socioeconomic characteristics by advertisement condition. Child BMI was not related to EAH. Mean kilocalories consumed during the EAH phase was greater among children exposed to the food advertisements (126.8, SD: 58.5) versus those exposed to the nonfood advertisements (97.3, SD: 52.3; P = .04), an effect driven by greater consumption of the advertised food (P < .01). There was no evidence of effect modification.

CONCLUSIONS

Findings suggest that food advertisement exposure may encourage obesogenic-eating behaviors among the very young.

Television food advertisement exposure and FTO rs9939609 genotype in relation to excess consumption in children

BACKGROUND/OBJECTIVE

Exposure to food advertisements may cue overeating among children, especially among those genetically predisposed to respond to food cues. We aimed to assess how television food advertisements affect eating in the absence of hunger among children in a randomized trial. We hypothesized that the Fat Mass and Obesity Associated Gene (FTO) rs9939609 single nucleotide polymorphism would modify the effect of food advertisements.

SUBJECTS/METHODS

In this randomized experiment, 200 children aged 9–10 years old were served a standardized lunch and then shown a 34-minute television show embedded with either food or toy advertisements. Children were provided with snack food to consume ad libitum while watching the show and we measured caloric intake. Children were genotyped for rs9939609 and analyses were conducted in the overall sample and stratified by genotype. A formal test for interaction of the food ad effect on consumption by rs9939609 was conducted.

RESULTS

172 unrelated participants were included in this analysis. Children consumed on average 453 (SD=185) kCals during lunch and 482 (SD=274) kCals during the experimental exposure. Children who viewed food advertisements consumed an average of 48 kCals (95% CI: 10, 85; P=0.01) more of a recently advertised food than those who viewed toy advertisements. There was a statistically significant interaction between genotype and food advertisement condition (P for interaction = 0.02), where the difference in consumption of a recently advertised food related to food advertisement exposure increased linearly with each additional FTO risk allele, even after controlling for BMI percentile.

CONCLUSIONS

Food advertisement exposure was associated with greater caloric consumption of a recently advertised food, and this effect was modified by an FTO genotype. Future research is needed to understand the neurological mechanism underlying these associations.

Understanding eating in the absence of hunger among young children: a systematic review of existing studies

BACKGROUND

Eating in the Absence of Hunger (EAH), or consuming highly palatable foods when satiated, is one behavioral pathway that may lead to childhood obesity. EAH is an objective, laboratory-based measure. A more comprehensive understanding of potential determinants of EAH could inform childhood obesity programs outside of a laboratory setting.

OBJECTIVE

Systematic review of EAH experiments to identify individual, familial, and societal-level correlates of EAH among children 12 years of age or younger.

DESIGN

1487 studies were retrieved from five electronic databases (Medline [PubMed], Web of Science, Cochrane Library, CINAHL, PsycINFO). Eligible studies were those that measured EAH as initially operationalized in a laboratory setting enrolling children ≤12 years or reporting age-specific results for children ≤12 years. Only articles written in English were included.

RESULTS

12 cross-sectional, six prospective, and one behavioral-intervention studies were included in the review. EAH was observable among boys and girls; absolute levels of EAH increased with age; and maternal feeding styles were associated with EAH among girls. The most consistent evidence supported increased levels of EAH among overweight and obese versus normal weight children, both cross-sectionally and prospectively. Two studies supported a genetic component to EAH.

CONCLUSIONS

Studies enrolling independent samples support a positive association between weight status and EAH among children; studies addressing causality are needed. Other various individual, genetic, and familiar characteristics were associated with EAH, yet studies among more heterogeneous sample populations are needed to confirm findings. Studies addressing societal-level factors related to EAH were absent.