Association of Apolipoprotein L-1 polymorphisms with blood pressure in three multi-ethnic African studies

# Background Genetic variants in the Apolipoprotein L1 (APOL1) gene greatly increase risk for chronic kidney disease in African Americans. We hypothesized that the APOL1 renal risk alleles would be associated with higher blood pressure in Africans. # Methods We used data from three multi-ethnic, population-based studies from Kenya, Ghana, and Nigeria to examine the association between ethnic group prevalence of APOL1 risk variants and blood pressure. Using available genotype data, we were able to link ethnic group status to APOL1 risk variant frequency in 10 423 persons. # Results Age, sex, body mass index, and frequency of the APOL1 high-risk genotype (two risk alleles) were associated with mean systolic blood pressure (SBP). In the adjusted model, a 1% higher prevalence of the APOL1 risk genotype was associated with 0.18 mmHg (95% confidence interval CI 0.05-0.32) higher systolic blood pressure (SBP). # Conclusions Mean SBP was 5 mmHg higher in African ethnic groups where nearly a third of persons carry two high risk APOL1 alleles, compared with ethnic groups where homozygosity is rare. Since uncontrolled blood pressure predisposes to high risks for death and substantial disability prior to development of end-stage kidney disease, studies exploring the link between the APOL1 risk alleles and blood pressure are crucial to understanding the full implications of APOL1 genetic variation in Africa.