Abstract Body (Do not enter title and authors here): Background: Despite a higher prevalence of coronary heart disease risk factors, people of African genetic ancestry have less coronary atherosclerosis than whites. In part, this is thought to be due to the less atherogenic lipoprotein profile observed in people with African genetic ancestry, characterized by lower triglycerides (trig) and higher HDL cholesterol. However, many of these studies primarily focus on African Americans, which have more European admixture and lie within a unique sociodemographic context, compared to other African-descendant populations, like Afro-Caribbeans.
Research Question: Hence, we tested the association of African genetic ancestry with lipid profiles in men of African ancestry living in the Caribbean.
Methods: The Tobago Health Study (THS) is a population-based observational study of Afro-Caribbean men aged 40+ years living on the island of Tobago. Genetic ancestry was derived from 119 ancestry informative markers genotyped using the Sequenom mass array panel. Fasting lipid profiles, including HDL, LDL, trig, and total cholesterol, were measured in 1762 men not on lipid-lowering medication using standard techniques. Dyslipidemia was defined as having any of the following: HDL<40mg/dL, trig≥200mg/dL, or LDL-C≥160mg/dL. Hypertriglyceridemia was defined as trig≥200mg/dL. Linear and logistic regression were used to assess African genetic ancestry’s relationship with lipid profiles adjusted for age.
Results: In these THS men the mean age was 58.8 years (SD=10.3), and mean BMI was 27.35kg/m² (SD=4.8). Mean lipoproteins were HDL=49.8mg/dL (SD=13.0), LDL=132.8 mg/dL (SD=40.1), trig=110.9 mg/dL (SD=56.9), and total cholesterol=204.8mg/dL (SD=43.7), resulting in 13% dyslipidemia and 6.4% hypertriglyceridemia. After age-adjustment, a 1 SD greater African genetic ancestry was associated with 2.9% lower serum triglycerides (P=0.033) and 19% lower odds of having hypertriglyceridemia (P=0.027), but was not associated with general dyslipidemia or HDL, LDL, or total cholesterol levels (all P>0.05).
Discussion: These results in an Afro-Caribbean population further confirm prior research that suggests African genetic ancestry is associated with lipoprotein profiles. These results underlie the importance of understanding the limitations of lipid profile benchmarks in the context of African genetic ancestry. Further studies are needed to identify the genetic loci that control triglyceride levels in individuals with African genetic ancestry.