title: Interactions with the MC4R rs17782313 variant, mental stress and energy intake and the risk of obesity in Genome Epidemiology Study.
abstract: BACKGROUND
  The melanocortin-4 receptor (MC4R) regulates metabolism by modulating eating behavior and MC4R variants (rs17782313 and rs571312) are associated with obesity in Asians and Caucasians. However, the impact of their interactions with nutritional and lifestyle factors on obesity are poorly described. Therefore, we investigated the interaction of MC4R variants and dietary patterns on the risk of obesity in Korean middle-aged adults.
  
  
  METHODS
  Data collected included, genetic variations, anthropometric and biochemical measurements, dietary and lifestyle habits, and food intake. Data were obtained from the 8830 adults aged 40-69 years in the Ansung and Ansan cohort of the Korean Genome Epidemiology Study.
  
  
  RESULTS
  The MC4R rs18882313 minor allele had a higher frequency in the obese group (P < 0.01). MC4R genotypes were not associated with differences in daily energy and macronutrient intakes. However, the intakes of processed foods and fat (as percentages of energy) were significantly higher and intake of fruits were significantly lower in subjects with MC4R minor alleles (P < 0.05). Interestingly, there was a positive interaction between MC4R variants and mental stress levels that were associated with the risk of obesity after adjusting for age, gender, residence area, daily energy intake, smoking status and physical activity (interaction P = 0.0384). Only in subjects with high stress were MC4R minor alleles associated with higher BMIs after adjusting for confounders. The association was present without modulating energy and nutrient intake. In the group with energy intakes higher than estimated energy requirement (EER), subjects with MC4R minor alleles had higher BMIs than those with the major alleles (P < 0.001).
  
  
  CONCLUSIONS
  The interactions of mental stress and energy intakes with the MC4R minor allele genotype might be associated with increased risk of obesity in Korean adults. This research might identify subjects with a specific MC4R minor alleles as a human subset of people with a low metabolic tolerance for excessive energy intake, especially when under stress.
authors.affiliation: Department of Food and Nutrition, Obesity/Diabetes Research Center, Hoseo University, 165 Sechul-Ri, BaeBang-Yup, Asan-Si, Chung Nam-Do 336-795 South Korea.
authors.forename: Sunmin
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of R&D, Daily Manufacturing Inc., Rockwell, NC USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Daily
authors.affiliation: Department of Food and Nutrition, Obesity/Diabetes Research Center, Hoseo University, 165 Sechul-Ri, BaeBang-Yup, Asan-Si, Chung Nam-Do 336-795 South Korea.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Science, Hoseo University, Asan, South Korea.
authors.forename: Hyun Seok
authors.initials: HS
authors.lastname: Jin
authors.affiliation: Center for Biomedical Science, Korea National Institute of Health, Cheongju, South Korea.
authors.forename: Hye Ja
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Nanobiomechatronics, Hoseo University, Asan, South Korea.
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Lee
keywords: Dietary intake; Food preference; Genotype; Korean Genome Epidemiology Study; Melanocortin-4 receptor