Association Between DRD2 Genotypes And Exercise Habits

PURPOSE: Exercise is important to maintain human health and prevent non-communicable diseases. Twin studies have indicated that genetic factors play an important role in physical activity and the exercise habit. However, there have been very few reports on the relationship between specific genes and exercise habit in humans. This study investigated the association between exercise habits and several polymorphisms of the dopamine D2 receptor (DRD2) gene, which plays a role in movement control as well as in reward mechanisms. METHODS: Seven-hundred twenty one healthy adults (men: 188, women: 533) aged 24-85 participated in this study. Exercise habits in the past year and in the period from childhood to adolescence were assessed using a questionnaire. Ten SNPs (rs1800497, rs6279, rs6277, rs6275, rs1076560, rs1076562, rs2471857, rs4936270, rs7131056, rs11214611) were selected based on PubMed searches and HapMap Projects. These SNPs were then genotyped via the TaqMan SNP genotyping assay. RESULTS: The percentages of individuals that exercised in the past year and in the period from childhood to adolescence were 50.3% and 66.0%, respectively. There was no significant association between the DRD2 genotypes and exercise habits in the past year. However, there were significant associations between six SNPs (rs1800497, rs6279, rs6275, rs1076560, rs1076562, rs2471857) and exercise habits in the period from childhood to adolescence. The rs1076560 (C>T) showed the smallest p-value for association with exercise habit (p = 0.001). For this SNP, the percentages of individuals that exercised and that did not exercise in this period are as follows: CC- 34.2% vs 47.3%, CA-49.8% vs 42.9%, AA-16.0% vs 9.9%. Based on the Haploview analysis, 6 SNPs associated with exercise habits were included in same LD block. CONCLUSIONS: Six SNPs in the same LD block were associated with exercise habits in the period from childhood to adolescence. Especially, the SNP of rs1076560 was suggested to be responsible for exercise habits. Further functional studies and/or replication studies are necessary to confirm these findings.