title: The prevalence of hypovitaminosis D and secondary hyperparathyroidism in obese Black Americans.
abstract: BACKGROUND
  Both obesity (body mass index, BMI > or = 30 kg/m2) and Black race are associated with a higher risk of vitamin D deficiency and secondary hyperparathyroidism. We hypothesized the risk of hypovitaminosis D would therefore be extraordinarily high in obese Black adults.
  
  
  OBJECTIVE
  To study the effects of race and adiposity on 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (iPTH).
  
  
  METHODS
  Cross-sectional study of 379 Black and White adults from the Washington D.C. area. BMI ranged from 19.9 to 58.2 kg/m2.
  
  
  METHODS
  Prevalence of hypovitaminosis D [25(OH)D < 37.5 nmol/l] and secondary hyperparathyroidism [25(OH)D < 37.5 nmol/l with iPTH > 4.2 pmol/l].
  
  
  RESULTS
  Obese Black subjects had lower mean 25(OH)D, 40.3 (SD, 20.3) nmol/l, compared with obese Whites, 64.5 (29.7), P < 0.001, nonobese Blacks, 53.3 (26.0), P = 0.0025 and nonobese Whites, 78.0 (33.5), P < 0.001. The prevalence of hypovitaminosis D increased with increasing BMI, and was greater (P < 0.001) in Blacks than Whites within all BMI categories examined. Among subjects with BMI > or = 35 kg/m2, 59% of Blacks vs 18% of Whites had hypovitaminosis D (odds ratio 6.5, 95% confidence interval 3.0-14.2). iPTH was negatively correlated with 25(OH)D (r = -0.31, P < 0.0001), suggesting those with hypovitaminosis D had clinically important vitamin D deficiency with secondary hyperparathyroidism. For secondary hyperparathyroidism 35.2% of Blacks met the criteria, compared to 9.7% of Whites (OR 3.6, CI 1.5-98.8).
  
  
  CONCLUSIONS
  Obese Black Americans are at particularly high risk for vitamin D deficiency and secondary hyperparathyroidism. Physicians should consider routinely supplementing such patients with vitamin D or screening them for hypovitaminosis D.
authors.affiliation: Unit on Growth and Obesity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1103, USA.
authors.forename: Lisa B
authors.initials: LB
authors.lastname: Yanoff
authors.forename: Shamik J
authors.initials: SJ
authors.lastname: Parikh
authors.forename: Amanda
authors.initials: A
authors.lastname: Spitalnik
authors.forename: Blakeley
authors.initials: B
authors.lastname: Denkinger
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Sebring
authors.forename: Pamela
authors.initials: P
authors.lastname: Slaughter
authors.forename: Theresa
authors.initials: T
authors.lastname: McHugh
authors.forename: Alan T
authors.initials: AT
authors.lastname: Remaley
authors.forename: Jack A
authors.initials: JA
authors.lastname: Yanovski
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D003430:Cross-Sectional Studies; D015930:Diet Records; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000150:complications / Q000208:ethnology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications / Q000208:ethnology*; D015995:Prevalence; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000208:ethnology*; D044465:White People
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D