Admixture Mapping of Obesity‐related Traits in African Americans: The Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Obesity is an important cause of morbidity and mortality worldwide. In the United States, the prevalence of obesity is higher in African Americans than whites, even after adjustment for socioeconomic status (SES). This leads to the hypothesis that differences in genetic background may contribute to racial/ethnic differences in obesity‐related traits. We tested this hypothesis by conducting a genome‐wide admixture mapping scan using 1,350 ancestry‐informative single‐nucleotide polymorphisms (SNPs) in 3,531 self‐identified blacks from the Atherosclerosis Risk in Communities (ARIC) study. We used these markers to estimate the overall proportions of European ancestry (PEAs) for each individual and then scanned for the association between PEA and obesity‐related traits (both continuous and dichotomous) at each locus. The median (interquartile range) PEA was 0.151 (0.115). PEA was inversely correlated with continuous BMI, weight, and subscapular skinfold thickness, even after adjusting for socioeconomic factors. In contrast, PEA was positively correlated with BMI‐adjusted waist circumference. Using admixture mapping on dichotomized traits, we identified a locus on 2p23.3 to be suggestively associated with BMI (locus‐specific lod = 4.11) and weight (locus‐specific lod = 4.07). After adjusting for global PEA, each additional copy of a European ancestral allele at the 2p23.3 peak was associated with a BMI decrease of ∼0.92 kg/m2 (P = 2.9 × 10−5). Further mapping in this region on chromosome 2 may be able to uncover causative variants underlying obesity, which may offer insights into the control of energy homeostasis.

Race-Related Differences in Left Ventricular Structural and Functional Remodeling in Response to Increased Afterload

“…(27) Briefly, genotyping was performed on stored DNA from visit 1 using the Illumina BeadLab platform at the Center for Inherited Disease Research (Johns Hopkins University, Baltimore). (28) Blind duplicate genotypes were performed, as part of a quality control program, and had a mismatch rate of 0.1%.…”

Relationship between diabetes risk and admixture in postmenopausal African-American and Hispanic-American women

“…However, these studies have examined relatively small participant sets (<1000 participants) and have reported substantial confounding by socioeconomic factors. For AFA populations, although several studies have examined the correlation between AFR (or EUR) admixture and adiposity measures [5, 8, 18, 19], investigations on the admixture–diabetes association have been limited. To our knowledge, only one study addressed this issue and reported that a higher AFR admixture was observed in AFAs with diabetic end-stage renal disease [20].…”

Lipoprotein lipase variants interact with polyunsaturated fatty acids for obesity traits in women: Replication in two populations

“…Obesity in the US has reached an overall prevalence of nearly 34% [1], with greater prevalence in some ethnic minorities [2], which might be related to differences in genetic background and behavioral factors [3–5]. The investigation of genetic variants for obesity in conjunction with behavioral factors, especially diet, may benefit development of more specific strategies to ameliorate susceptibility to weight gain.…”