Determinants of 25-hydroxyvitamin D levels in African-American and Caucasian male veterans.
CONCLUSIONS
Among 307 males seen in VA Medical Center, independent determinants (p < 0.01 for all) of serum 25-hydroxyvitamin D [25(OH)D] levels included race, vitamin D supplements, BMI, dietary calcium intake and smoking, but not age. Negative association between 25(OH)D and parathyroid hormone (PTH) was similar for Caucasian and African-American men.


BACKGROUND
In this prospective cohort study, we examined determinants of serum 25-hydroxyvitamin D [25(OH)D] levels and the relationship between 25(OH)D and PTH levels and body mass index (BMI).


METHODS
Male veterans (n = 307) were recruited at a VA Medical Center. Serum levels of PTH and 25(OH)D were obtained. Surveys and chart reviews were completed. Vitamin D insufficiency was defined as 25(OH)D <30 ng/ml. Univariate and multivariate regression analyses were performed.


RESULTS
Among 232 African-American (AA) men (mean +/- SD), 25(OH)D level (21.4 +/- 10.4 ng/ml) was lower and prevalence of insufficiency (80%) was higher than among 75 Caucasians (C; 28.5 +/- 11.1 ng/ml and 53%, respectively, p < 0.01 for both). In multivariate regression analysis, independent determinants (p < 0.01 for all) of 25(OH)D levels included AA race, vitamin D supplements, BMI, dietary calcium intake, and smoking. Despite lower 25(OH)D levels in African-Americans, PTH levels were similar to those seen in Caucasians. There was a significant (p < 0.02) negative linear association between 25(OH)D and PTH in African-American (r(2) = 0.05) and Caucasian (r(2) = 0.08) men, and there was no difference between the slopes of the relationship.


CONCLUSIONS
25(OH)D levels are determined by modifiable risk factors such as vitamin D supplementation in both AA and C males. The negative association between 25(OH)D and PTH is similar between the two races.
Benjamin
A
A
Section of Endocrinology and Metabolism, Department of Medicine, University of Illinois Medical Center, MC 640, 1819 West Polk Street, Chicago, IL 60612, USA.
Moriakova
A
A
Akhter
N
N
Rao
D
D
Xie
H
H
Kukreja
S
S
Barengolts
E
E
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D015992:Body Mass Index; D002136:Calcium, Dietary / Q000008:administration & dosage; D002641:Chicago / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D011446:Prospective Studies; D012907:Smoking / Q000097:blood / Q000208:ethnology; D014728:Veterans / Q000706:statistics & numerical data; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000208:ethnology; D044465:White People / Q000706:statistics & numerical data*
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D