Polymorphisms of leptin (G2548A) and leptin receptor (Q223R and K109R) genes and blood pressure during pregnancy and the postpartum period: A cohort

Abstract

BACKGROUND The genetic component related to blood pressure (BP) changes during pregnancy is still not elucidated. Thus, the aim of the study was to evaluate the association between leptin and leptin receptor polymorphisms and systolic (SBP) and diastolic BP (DBP) variation during pregnancy and the postpartum period. METHODS Prospective cohort of 146 women followed at a Public Health Center in Rio de Janeiro, Brazil, during pregnancy and the postpartum. SBP and DBP (mm Hg) were measured using an automatic sphygmomanometer. DNA was extracted by phenol-chloroform protocol and leptin (G2548A) and leptin receptor genes (Q223R and K109R) polymorphisms were genotyped using real-time PCR method. Statistical analyses included longitudinal linear mixed-effect models. RESULTS Adjusted longitudinal models showed that women carrying the G-allele of leptin gene's polymorphism began pregnancy with higher BP levels compared to the AA genotype and their levels remained higher throughout pregnancy and the postpartum period (βSBP = 4.5; 95% confidence interval (CI) = 1.0-8.0; P = 0.012; βDBP = 2.9; 95% CI = 0.1-5.8; P = 0.040). There was a significant interaction between leptin gene polymorphism and body mass index (BMI), in which the effect of BMI on increasing BP was steeper in women homozygous for the A-allele, compared with those who had at least one G-allele (βG-allele#BMI = -0.8; 95% CI = -1.5 to -0.1; P = 0.022). We did not find significant associations between leptin receptor polymorphisms and BP changes. CONCLUSIONS The G-allele of leptin gene polymorphism (G2548A) was associated with increased BP levels during pregnancy and the postpartum. Furthermore, leptin polymorphism genotypes seem to modify the wellknown effect of BMI on BP.