Gender specific associations of the Trp64Arg mutation in the β3-adrenergic receptor gene with obesity-related phenotypes in a Mediterranean population:: interaction with a common lipoprotein lipase gene variation

Objective. To investigate the association between the Trp64Arg beta (3)-adrenergic receptor (ADRB3) mutation and obesity-related phenotypes in a Mediterranean Spanish population considering the effect of other genetic and environmental factors. Design and subject. Cross-sectional study in 1063 (476 men and 587 women) randomly selected from this population (aged: 18-68 years). Measurements. Anthropometric (weight, height and waist-to-hip ratio), blood pressure, biochemical (lipids, fasting glucose, and uric acid), life-style variables, and the Trp64Arg, HindIII-Lipoprotein lipase (LPL) and apolipoprotein E polymorphism. Results. Frequency of the Arg64 allele was low (0.051; 95% CI: 0.042-0.060). We found gender-specific associations between the Trp64Arg mutation and obesity related phenotypes. In men, carriers of the Arg64 variant had higher body mass index (BMI) (27.63 +/-3.81 vs. 26.34 +/-3.57 kg m(-2) P=0.049) and total cholesterol (5.85 +/-1.45 vs. 5.28 +/-1.06 mmol L-1; P=0.011) compared with wild-type individuals. Logistic regression analysis, revealed that the risk of overweight was two times higher in mate carriers of the Arg64 allele. In women, the Arg64 variant was only associated with higher fasting glucose (P=0.031). These genotype effects persisted after adjustment for age, genetic and life-style variables, For the LPL polymorphism, the H-/H- genotype was associated with lower BMI and with lower risk of overweight (OR: 0.49, 95% CI: 0.30-0.81) in both men and women. However, after adjustment for covariates, these associations only remained statistically significant (P<0.02) in women. Moreover, in women, a statistically significant interaction (P=0.026) between the LPL and the ADRB3 gene loci in determining BMI was found. Thus, the Arg64 allele was associated with a higher BMI only in H+/H+ women. Conclusions. The Trp64Arg mutation was associated with BMI and lipids in men. In women, an additional gone-gene interaction with the LPL-HindIII polymorphism may explain the results.