Vit D and parathyroid for AA
Clin Endocrinol (Oxf). 2009 Jul 28. [Epub ahead of print]
Relationship of vitamin D and parathyroid hormone to obesity and body composition in African Americans.
Valiña-Tóth AL, Lai Z, Yoo W, Abou-Samra A, Gadegbeku CA, Flack JM.
Department of Physiology, Wayne State University, School of Medicine, Detroit, MI, USA.
Background: Obesity disproportionately affects African Americans (AA) (especially women), and is linked to depressed 25-hydroxyvitamin D (25-OH D) and elevated parathyroid hormone (PTH). The relationship of 25-OH D and PTH to body composition and size in AA is not well known. Objective: To determine the relationship of 25-OH D and PTH levels with body composition and anthropometric measures. Design: A cross-sectional study was conducted in 98 healthy, overweight, adult AA enrolled in an NIH/NIEHS-sponsored weight loss/salt sensitivity. Measurements: Multivariable linear regression analyses were used to explore the relationship of 25-OH D and PTH with body composition, determined by dual-energy X-ray absorptiometry, and anthropometric measures. Body composition and size were contrasted across vitamin D/PTH groups using general linear models: 1) normal (25-OH D > 50 nmol/l, PTH </= 65 pg/ml), 2) low 25-OH D and normal PTH, and 3) low 25-OH D and high PTH. Results: Age, sex and season-adjusted regression analyses showed that PTH was directly correlated with total (p=0.02), truncal (p=0.03) and extremity (p=0.03) fat mass while 25-OH D was related inversely to truncal fat mass (p=0.02). Total fat mass in groups 1-3, respectively, was 30.0, 34.0, to 37.4 kg (p=0.008); truncal fat mass was 13.4, 15.9 and 17.6 kg (p=0.006) and extremity fat mass was 15.8, 16.9 and 19.7 kg (p=0.02). Lean mass did not differ across the 3 groups. Conclusions: Our findings show that lower 25-OH D and raised PTH are both correlated, though in opposite directions, with fat mass, fat distribution and anthropometric measures in adult AA.

PMID: 19656160 [PubMed - as supplied by publisher]