Gene-Environment Interaction for Blood Pressure among African American Women across Generations

African American women have the highest prevalence of hypertension and obesity of any group in the United States. African American girls have the highest incidence of obesity of any groups of children in the nation, and diagnoses of hypertension have been rising among this group. Because both genetic heredity and body mass index (BMI) are important risk factors for hypertension, this study examined the gene-BMI interaction for hypertension across the lifespan in two generations of African American women. Participants comprised of 868 African American women in the parent cohort and 322 in the offspring cohort from the Hypertension Genetic Epidemiology Network (HyperGEN) study, part of the Family Blood Pressure Program (FBPP). A total of 115 single-nucleotide polymorphisms (SNPs) were evaluated among the parent cohort and 491 among the offspring cohort for tests of SNP-BMI interaction using methods of false discovery rate (FDR; <.20) and examination of minor allele frequency (MAF; >.05) and Hardy-Weinberg equilibrium (>.10). One SNP (located in the CAPN 13 gene, rs1879282) passed adjustments for the multiple testing mentioned above and had a significant (p < .01) gene-BMI interaction on both systolic blood pressure (SBP) and diastolic blood pressure (DBP) among African American female offspring. The rs1879282 SNP is located on chromosome 2 on the calpain (CAPN) 13 gene, which is part of a family of cytosolic calcium-activated proteases involved in apoptosis, cell division, modulation of integrin-cytoskeletal interactions, and synaptic plasticity. This SNP was not available for testing in the African American parent cohort.