Interactions among the β2- and β3- adrenergic receptor genes and total body fat and abdominal fat level in the HERITAGE Family Study

OBJECTIVE AND SUBJECTS: Interactions between markers in the β2- and β3-adrenergic receptor (ADR) genes and total body fat and computerized tomography-measured abdominal fat phenotypes were studied in the HERITAGE Family Study cohort of Black (n=205; 81 males and 124 females) and White (n=415; 198 males and 217 females) subjects before and after an endurance training program. RESULTS: In Black subjects, β2- and β3-ADR gene variants showed evidence of interactions on changes in total body fat mass and abdominal fat area (P<0.005 and =0.010, respectively). Black subjects who were carriers of both β2-ADR Arg16 and β3-ADR Arg64 alleles had a greater decrease in total fat mass as well as abdominal total and subcutaneous, but not visceral fat areas in response to endurance training than subjects with other genotype combinations (P from 0.011 to 0.047). After correction for multiple tests, the findings remained essentially unchanged for total body fat mass and abdominal fat area, but became nonsignificant for subcutaneous fat area. The changes in abdominal fat correlated positively with the changes in fat mass (P<0.0001). The interactions between β2 and β3-ADR gene markers accounted for a maximum of 3% of the variances in the response of total fat mass and abdominal fat area to endurance training in Black subjects but it was not significant in White subjects. CONCLUSION: Interactions between sequence variants in the β2-β3-ADR gene contributed to the changes in fat mass and abdominal adiposity in response to endurance training in Black subjects.