Dopamine D4 receptor gene polymorphism (DRD4 VNTR) moderates real-world behavioural response to the food retail environment in children.
In plain language
The same neighborhood food environment may affect children differently
Studies of neighborhood food shops often find inconsistent relationships with diet. One possible explanation is that children differ in their responsiveness to the same surroundings. This study tested whether a variation in a dopamine receptor gene was associated with that difference.
Combining neighborhood, diet and genetic information. The analysis included 322 Montreal children aged four to twelve. Researchers mapped the proportion of local food retailers classified as healthful within three kilometers of each child’s home. They estimated dietary energy density from a food questionnaire and measured body mass index relative to age. Energy density describes how much energy a food provides for its weight, allowing the analysis to distinguish the composition of the diet from body size.
The genetic comparison concerned the seven-repeat version of DRD4, a gene involved in dopamine signaling. The study asked whether the relationship between the retail environment and children’s diet differed between carriers and non-carriers. This is a gene–environment interaction: an association with one factor depends on the other.
A dietary difference without a corresponding BMI finding. Children carrying the seven-repeat version had more energy-dense diets than non-carriers, and that difference was more pronounced in neighborhoods with proportionally more unhealthy food retailers. The analysis did not detect a comparable main or interaction effect for body mass index.
The result suggests that a dopamine-related genetic marker may identify variation in responsiveness to food surroundings. It also shows why diet and body weight should be examined separately: a behavioral association can be present without a measurable difference in body size at the same point in development.
This was an observational neighborhood study. Living near a shop does not establish that a child bought or ate food there, and the analysis cannot show that changing local retailers would produce the observed dietary difference. It provides a hypothesis to test in other populations and with more direct measures of exposure and food choice.
Original abstract
Background Evidence for the impact of the food retailing environment on food-related and obesity outcomes remains equivocal, but only a few studies have attempted to identify sub-populations for whom this relationship might be stronger than others. Genetic polymorphisms related to dopamine signalling have been associated with differences in responses to rewards such as food and may be candidate markers to identify such sub-populations. This study sought to investigate whether genetic variation of the dopamine D4 receptor gene (DRD4 exon III 48 bp VNTR polymorphism) moderated the association between local exposure to food retailers on BMI and diet in a sample of 4 to12-year-old children.
Methods Data collected from a birth cohort and a community cross-sectional study conducted in Montreal, Canada, were combined to provide DRD4 VNTR polymorphism data in terms of presence of the 7-repeat allele (DRD4-7R) for 322 children aged between 4 and 12 (M (SD): 6.8(2.8) y). Outcomes were Body Mass Index (BMI) for age and energy density derived from a Food Frequency Questionnaire. Food environment was expressed as the proportion of local food retailers classified as healthful within 3 km of participants' residence. Linear regression models adjusted for age, sex, income, cohort, and geographic clustering were used to test gene*environment interactions.
Results A significant gene*food environment interaction was found for energy density with results indicating that DRD4-7R carriers had more energy dense diets than non-carriers, with this effect being more pronounced in children living in areas with proportionally more unhealthy food retailers. No evidence of main or interactive effects of DRD4 VNTR and food environment was found for BMI.
Conclusions Results of the present study suggest that a genetic marker related to dopamine pathways can identify children with potentially greater responsiveness to unhealthy local food environment. Future studies should investigate additional elements of the food environment and test whether results hold across different populations.
Reproduced from the original publication under CC BY 4.0. Wording unchanged; layout and typography normalized.
Paquet C, Portella AK, Moore S, Ma Y, Dagher A, Meaney MJ, Kennedy JL, Levitan RD, Silveira PP, Dubé L. Dopamine D4 receptor gene polymorphism (DRD4 VNTR) moderates real-world behavioural response to the food retail environment in children. BMC Public Health. 2021;21(1):145. doi: 10.1186/s12889-021-10160-w. PMID: 33530977.
Read the original publication and abstract