Australian Centre for Precision Health, Allied Health and Human Performance, University of South Australia, Adelaide, SA, Australia.
Faculté des Sciences de L'Administration, Université Laval, Québec, QC, Canada.
BMC Public Health. 2021 Feb 3;21(1):145. doi: 10.1186/s12889-021-10160-w.
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.
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.
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.
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.
有关食品零售环境对食品相关和肥胖结果影响的证据仍然存在争议，但只有少数研究试图确定这种关系可能比其他关系更强的亚人群。与多巴胺信号传导相关的遗传多态性与对食物等奖励的反应差异有关，可能是识别此类亚人群的候选标志物。本研究旨在调查多巴胺 D4 受体基因（DRD4 外显子 III 48bpVNTR 多态性）的遗传变异是否调节了当地食品零售商对 BMI 和饮食的暴露与 4 至 12 岁儿童样本之间的关联。
从加拿大蒙特利尔进行的一项出生队列研究和一项社区横断面研究中收集的数据进行了合并，为 322 名 4 至 12 岁（M（SD）：6.8（2.8）y）儿童提供了 DRD4VNTR 多态性存在 7 个重复等位基因（DRD4-7R）的数据。结果是基于食物频率问卷得出的年龄和能量密度的体重指数（BMI）。食品环境用参与者居住地 3 公里范围内分类为健康的当地食品零售商的比例来表示。使用调整年龄、性别、收入、队列和地理聚类的线性回归模型来测试基因*环境相互作用。
发现能量密度存在显著的基因*食品环境相互作用，结果表明，DRD4-7R 携带者的饮食比非携带者的能量密度更高，这种影响在居住在比例上不健康食品零售商较多的地区的儿童中更为明显。未发现 DRD4VNTR 和食品环境的主要或交互作用对 BMI 有影响。
本研究结果表明，与多巴胺途径相关的遗传标志物可以识别对不健康当地食品环境潜在反应更大的儿童。未来的研究应调查食品环境的其他要素，并检验结果在不同人群中是否成立。
