No association of the dopamine D2 receptor genetic bilocus score (rs1800497/rs1799732) on food addiction and food reinforcement in Chilean adults.

Purpose: Different systems regulate food intake. In the reward system, dopamine (DA) is the main neurotransmitter, and a variety of genetic variants (rs1799732 and rs1800497) are associated with addiction. Addiction is a highly polygenic disease, where each allelic variant adds a small amount of vulnerability. Polymorphisms rs1799732 and rs1800497 are associated with eating behavior and hedonic hunger, but links to food addiction remain unclear. Aim: To evaluate the association between the bilocus profile (rs1799732-rs1800497) of the dopaminergic pathway with food reinforcement and food addiction in Chilean adults. Methods: A cross-sectional study recruited a convenience sample of 97 obese, 25 overweight, and 99 normal-weight adults (18-35 years). Anthropometric measurements were performed by standard procedures and eating behavior was assessed using the: Food Reinforcement Value Questionnaire (FRVQ) and Yale Food Addiction scale (YFAS). The DRD2 genotypes were determined by TaqMan assays (rs1800497 and rs1799732). A bilocus composite score was calculated. Results: In the normal weight group, individuals who were heterozygous for the rs1977932 variant (G/del) showed higher body weight (p-value 0.01) and abdominal circumference (p-value 0.01) compared to those who were homozygous (G/G). When analyzing rs1800497, a significant difference in BMI was observed for the normal weight group (p-value 0.02) where heterozygous showed higher BMI. In the obese group, homozygous A1/A1 showed higher BMI in comparison to A1/A2 and A2/A2 (p-value 0.03). Also, a significant difference in food reinforcement was observed in the rs1800497, where homozygous for the variant (A1A1) show less reinforcement (p-value 0.01).In relation to the bilocus score in the total sample, 11% showed "very low dopaminergic signaling", 24.4% were "under", 49.7% showed "intermediate signaling", 12.7% showed "high" and 1.4% showed "very high". No significant genotypic differences were observed in food reinforcement and food addiction by bilocus score. Conclusions: The results indicate that the genetic variants rs1799732 and rs1800497 (Taq1A) were associated with anthropometric measurements but not with food addiction or food reinforcement in Chilean university students. These results suggest that other genotypes, such as rs4680 and rs6277, which affect DA signaling capacity through a multilocus composite score, should be studied. Level V: Evidence obtained from a cross-sectional descriptive study.

Association of the dopamine D2 receptor rs1800497 polymorphism with food addiction, food reinforcement, and eating behavior in Chilean adults.

PURPOSE: The regulation of food intake and body weight involves two interacting systems: (a) The homeostatic system (including biological regulators of hunger and satiety) and (b) the non-homeostatic system, (involving concepts of food reinforcement and food addiction). Studies have established a strong genetic component in eating behavior and obesity. The TaqI A1 polymorphism (rs1800497) has previously been associated with eating behavior, diminished dopamine D2 receptor (DRD2) density, higher body mass, and food reinforcement, but relations to food addiction remain unclear. AIM: To evaluate the association between the polymorphism rs1800497 with eating behavior, food reinforcement and food addiction in Chilean adults. METHODS: This cross-sectional study recruited a convenience sample of 97 obese, 25 overweight and 99 normal-weight adults (18-35 years). Anthropometric measurements were performed by standard procedures. Eating behavior was assessed using the: Yale Food Addiction Scale (YFAS), the Three Factor Eating Behavior Questionnaire and the Food Reinforcement Value Questionnaire (FRVQ). The DRD2 genotype (rs1800497) was determined by taqman assays. RESULTS: Twenty-two percentage of the participants met the criteria for food addiction. Food addiction was higher in women than men (26% vs 10.7%) and in obese compared to non-obese (40% vs 6%). There was no relationship between food addiction and DRD2 genotype. However when stratified by sex and nutritional status, obese female carriers of the A1 allele reported greater scores on emotional eating and snack food reinforcement compared to non-carriers. CONCLUSIONS: The DRD2 polymorphism is associated with some hedonic aspects of eating behavior, namely food reinforcement and emotional eating but not food addiction, and this association may be moderated by sex and obesity status, with obese women who are carriers of this genetic variant at higher risk. LEVEL OF EVIDENCE: Level V: evidence obtained from a cross-sectional descriptive study.

Development of the Ottawa Disordered Eating Screen for Youth: The ODES-Y.

OBJECTIVE: To develop a concise screening tool that allows for early identification of disordered eating in youth. STUDY DESIGN: In this 2-step classification accuracy study, questions for the Ottawa Disordered Eating Screen-Youth, a 2-question screening tool (index test), were conceptualized by clinician-scientists from tertiary care pediatric eating disorder and weight-related clinics, and was validated using retrospective data (2004-2010) from a community-based study, the Research on Eating and Adolescent Lifestyles (REAL) study. RESULTS: Analyses of contrast between the index test and the reference standard using data from 2892 (1714 females) students between grade 7 and grade 12 revealed classification statistics of 67.1% for sensitivity, 85.9% for specificity, 4.7 for positive likelihood ratio, 0.38 for negative likelihood ratio, 50.6% for positive predictive value, and 92.4% for negative predictive value for females and 61.1% for sensitivity, 93.9% for specificity, and 9.9 for positive likelihood ratio, 0.41 for negative likelihood ratio, 32.3% for positive predictive value, and 98.0% for negative predictive value for males. CONCLUSIONS: Our findings suggest that the index test has utility as a short and accurate screening tool for earlier detection of disordered eating thoughts and behaviors in youth. Additional research is needed to best determine how the index test can be administered to youth across various health care, school, public health, and surveillance settings in clinically sensitive pragmatic ways.

Physical activity and sedentary behavior in obese youth.

OBJECTIVE: To determine whether directly measured physical activity and sedentary behavior patterns of obese children presenting to a weight-management clinic differs from nationally representative samples of obese and normal-weight children. STUDY DESIGN: A cross-sectional comparison study of 3 groups of boys and girls between 8 and 18 years (mean, 13.4 years) was performed. A clinical group (n=56) seeking specialized care for obesity was compared with 2 nationally representative samples of children from the Canadian Health Measures Survey (CHMS): (1) body mass index>95th percentile (n=143); and (2) body mass index<85th percentile (n=958). RESULTS: Obese clinical and obese CHMS boys did not differ in daily moderate-to-vigorous physical activity (MVPA). Both obese groups engaged in less MVPA than normal-weight boys in the CHMS (P<.0006). Compared with normal-weight boys, obese boys had fewer days in which they accrued 60 or 30 minutes of MVPA (P=.006 and .01, respectively). Daily MVPA did not differ among the 3 groups of girls. Light activity in clinical boys was lower than in the normal weight CHMS boys, whereas clinical girls engaged in less light activity than both CHMS comparators. No differences were observed between groups for sedentary behavior. CONCLUSIONS: Obese youth, whether in clinic or the community, were not more sedentary than their normal-weight CHMS comparators. Although obese youth were less active, overall MVPA was low in all groups. This finding highlights the need for health professionals to target both physical activity and sedentary behavior in all children, rather than focusing on only children with obesity.