Skinfold thickness and blood pressure across C-344T polymorphism of CYP11B2 gene

To ascertain whether body adiposity is associated with the C-344T polymorphism of the CYP11B2 gene codifying for aldosterone synthase.

A cross-sectional epidemiological evaluation of a highly homogeneous unselected general population of Caucasians.

Lifestyle, medical history, anthropometrics, subscapular, triceps and suprailiac skinfold thickness, lying blood pressure and biochemical measures were recorded in a population-based study among 1386 unselected subjects (56.5% women) living in a secluded valley. All were genotyped for C-344T allele status. Continuous variables were compared across genotypes with analysis of covariance and correlations evaluated using the Pearson method. Odds ratios (OR) were calculated for the TT and CT genotype versus the CC homozygotes and compared with the T-carriers with a logistic model.

The C-344T genotypic frequency did not deviate from Hardy-Weinberg equilibrium. In women, higher values of triceps and subscapular skinfold thickness were found in the CC homozygotes than in the T-carriers. In this sex, skinfold thickness also directly correlated with both systolic and diastolic blood pressure in the T-carriers only. The logistic regression for the dependent variable arterial hypertension showed an influence of triceps [OR 1.07, 95% confidence interval (CI) 1.02-1.12, P=0.006], subscapular (OR 1.13, 95% CI 1.06-1.20, P<0.0001) and suprailiac (OR 1.08, 95% CI 1.01-1.15, P=0.03) skinfold in T-carrier women only. These relationships were not detectable in men. The aldosterone-to-renin ratios were comparable across genotypes and sexes.

The C-344T polymorphism of the CYP11B2 gene seems to exert a sex-specific influence on body adiposity, independent of adrenal aldosterone.