Associations of Adiponectin with Individual European Ancestry in African Americans: the Jackson Heart Study

• Main Authors: Aurelian eBidulescu, Shweta eChoudhry, Solomon K Musani, Sarah G Buxbaum, Jiankang eLiu, Charles N Rotimi, James G Wilson, Herman A Taylor, Gary H Gibbons
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-02-01
• Series: Frontiers in Genetics
• Subjects: Adiponectin; African Americans; Insulin Resistance; Obesity; cohort study; minorities
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fgene.2014.00022/full

Background: Compared with European Americans, African Americans (AA) exhibit lower levels of the cardio-metabolically protective adiponectin even after accounting for adiposity measures. Because few studies have examined in AA the association between adiponectin and genetic admixture, a dense panel of ancestry informative markers (AIMs) was used to estimate the individual proportions of European ancestry (PEA) for the African Americans enrolled in a large community-based cohort, the Jackson Heart Study (JHS). We tested the hypothesis that plasma adiponectin and PEA are directly associated and assessed the interaction with a series of cardio-metabolic risk factors.<br/><br/>Methods: Plasma specimens from 1,439 JHS participants were analyzed by ELISA for adiponectin levels. Using pseudo-ancestral population genotype data from the HapMap Consortium, PEA was estimated with a panel of up to 1,447 genome-wide preselected AIMs by a maximum likelihood approach. Interaction assessment, stepwise linear and cubic multivariable-adjusted regression models were used to analyze the cross-sectional association between adiponectin and PEA.<br/><br/>Results: Among the study participants (62% women; mean age 48 ± 12 years), the median (interquartile range) of PEA was 15.8 (9.3)%. Body mass index (p = 0.04) and insulin resistance (p = 0.0001) modified the association between adiponectin and PEA. Adiponectin was directly and linearly associated with PEA (β = 0.62 ± 0.28, p = 0.03) among non-obese (n = 673) and insulin sensitive participants (n = 1,141; β = 0.74 ± 0.23, p = 0.001), but not among those obese or with insulin resistance. No threshold effect was detected for non-obese participants.<br/><br/>Conclusions: In a large African American population, the individual proportion of European ancestry was linearly and directly associated with plasma adiponectin among non-obese and non insulin-resistant participants, pointing to the interaction of genetic and metabolic factors influencing adiponectin levels.