Browsing by Subject "African ancestry"

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    Association of Circulating Renin and Aldosterone With Osteocalcin and Bone Mineral Density in African Ancestry Families
    (American Heart Association, 2016-05) Kuipers, Allison L.; Kammerer, Candace M.; Pratt, J. Howard; Bunker, Clareann H.; Wheeler, Victor W.; Patrick, Alan L.; Zmuda, Joseph M.; Medicine, School of Medicine
    Hypertension is associated with accelerated bone loss, and the renin-angiotensin-aldosterone system is a key regulator of blood pressure. Although components of this system are expressed in human bone cells, studies in humans are sparse. Thus, we studied the association of circulating renin and aldosterone with osteocalcin and bone mineral density. We recruited 373 African ancestry family members without regard to health status from 6 probands (mean family size: 62 and relative pairs: 1687). Participants underwent a clinical examination, dual-energy x-ray absorptiometry, and quantitative computed tomographic scans. Renin activity, aldosterone concentration, and osteocalcin were measured in fasting blood samples. Aldosterone/renin ratio was calculated as aldosterone concentration/renin activity. All models were analyzed using pedigree-based variance components methods. Full models included adjustment for age, sex, body composition, comorbidities, lifestyle factors, blood pressure, and antihypertensive medication. Higher renin activity was significantly associated with lower total osteocalcin and with higher trabecular bone mineral density (both P<0.01). There were also significant genetic correlations between renin activity and whole-body bone mineral density. There were no associations with aldosterone concentration in any model and results for aldosterone/renin ratio were similar to those for renin activity. This is the first study to report a significant association between renin activity and a marker of bone turnover and bone mineral density in generally healthy individuals. Also, there is evidence for significant genetic pleiotropy and, thus, there may be a shared biological mechanism underlying both the renin-angiotensin-aldosterone system and bone metabolism that is independent of hypertension.
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    Racial Differences in Predictive Capacity of Educational Polygenic Scores on Physical Limitations for Older Adults
    (Oxford University Press, 2024-12-31) Catt, Wade; Williams, Micah; Latham-Mintus, Kenzie; Medicine, School of Medicine
    This research examined whether educational polygenic scores were associated with physical limitations among older adults with European or African ancestry. In the European ancestry sample, we found that education polygenic scores were significantly associated with physical limitations in the age- and sex-adjusted models; however, education polygenic scores were no longer associated with physical limitations after adjusting for current socioeconomic status and health risk factors. In the African ancestry sample, education polygenic scores were not associated with physical limitations. Observed educational attainment was a robust predictor of physical limitations in both samples. This research demonstrates the racial inequalities in the predictive capacity of educational polygenic scores. We hypothesize that this disparity is a result of structural barriers to educational attainment by race and/or racial inequities in data collection. Both explanations stem from structural racism and highlight the limited usefulness of polygenic scores for clinical decision-making. We use these findings to explore competing theoretical explanatory frameworks of the utility and limitations of the use of polygenic scores in social and health sciences.