The MC4R genotype is associated with postpartum weight reduction and glycemic changes among women with prior gestational diabetes: longitudinal analysis.

The genetic variants near the Melanocortin-4 receptor gene (MC4R), a key protein regulating energy balance and adiposity, have been related to obesity and glucose metabolism. We aimed to assess whether the MC4R genotype affected longitudinal changes in body weight and glucose metabolism biomarkers among women with prior gestational diabetes mellitus (GDM). The MC4R genotype, postpartum weight reduction, and glycemic changes between after delivery and pregnancy were assessed in a cohort of 1208 Chinese women who had experienced GDM. The adiposity-increasing allele (C) of the MC4R variant rs6567160 was associated with greater postpartum increase of HbA1c (ß = 0.08%; P = 0.03) and 2-hour OGTT glucose concentrations (ß = 0.25 mmol/L; P = 0.02). In addition, we found an interaction between the MC4R genotype and postpartum weight reduction on changes in fasting plasma glucose (P-interaction = 0.03). We found that the MC4R genotype was associated with postpartum glycemic changes; and the association with fasting glucose were significantly modified by postpartum weight reduction in women who had experienced GDM.

Sugar-sweetened beverage intake, chromosome 9p21 variants, and risk of myocardial infarction in Hispanics.

BACKGROUND: Chromosome 9p21 variants are among the most robust genetic markers for coronary artery disease (CAD), and previous studies have suggested that genetic effects of this locus might be modified by dietary factors. Intake of sugar-sweetened beverages (SSBs), which are the main dietary source of added sugar, has been shown to interact with genetic factors in affecting CAD risk factors such as obesity. OBJECTIVE: We aimed to test whether SSB intake modified the association between chromosome 9p21 variants and CAD risk in Hispanics living in Costa Rica. DESIGN: The current study included 1560 incident cases of nonfatal myocardial infarction (MI) and 1751 population-based controls. Three independent single nucleotide polymorphisms (SNPs) at the chromosome 9p21 locus were genotyped. SSB intake was assessed with the use of a food-frequency questionnaire and was defined as the frequency of intake of daily servings of sweetened beverages and fruit juice. RESULTS: We showed a significant interaction between SSB intake and one of the 3 variants (i.e., rs4977574) on MI risk. The per­risk allele OR (95% CI) of rs4977574 for MI was 1.44 (1.19, 1.74) in participants with higher SSB consumption (>2 servings/d), 1.21 (1.00, 1.47) in those with average consumption (1­2 servings/d), and 0.97 (0.81, 1.16) in subjects with lower consumption (<1 serving/d; P-interaction = 0.005). A genetic risk score derived from the sum of risk alleles of the 3 SNPs also showed a significant interaction with SSB intake on MI risk (P-interaction = 0.03). CONCLUSION: Our data suggest that unhealthy dietary habits such as higher intake of SSBs could exacerbate the effects of chromosome 9p21 variants on CAD.