Weight loss is associated with increased serum 25(OH)vitamin D in overweight or obese women

Cheryl L. Rock1, Dennis D. Heath1, Shirley W. Flatt1, Njeri Karanja2, Bilge Pakiz1, Nancy E. Sherwood3 and Cynthia A. Thomson4
1 UCSD, La Jolla, CA
2 Kaiser Permanente, Center for Health Research, Portland, OR
3 Univ. of Minnesota, Minneapolis, MN
4 University of Arizona, Tucson, AZ
FASEB Journal 917.2

Circulating 25(OH)D concentration has been linked with differential risk and progression of disease. Obese individuals have lower circulating 25(OH)D, possibly due to sequestration in body fat. The objective of this study was to examine the effect of weight loss on 25(OH)D concentration in overweight or obese women in a clinical trial of a diet and lifestyle modification program. Study participants (n=442) were 44(10) (meanSD) yrs, with BMI 33.8(3.4) kg/m2, weight 92.1(10.7) kg, and waist circumference 108.6(9.6) cm. One year data are available for 92% of participants (n=406), and weight loss averaged – 9.7(7.7) kg for women assigned to intervention and – 2.8(6.8) kg for control groups, a relative weight loss of – 11% and – 3%, respectively. Total serum 25(OH)D was measured via chemiluminescent DiaSorin assay; 25(OH)D2 and 25(OH)D3 were separated and quantified with reversed phase HPLC methodology. Baseline 25(OH)D was 21(10) ng/mL, significantly associated with degree of obesity and race/ethnicity.

In women who lost ?10% of body weight at 12 mos, 25(OH)D increased to 23(10) ng/mL.

In multivariate analysis, change in 25(OH)D over one year was significantly associated with degree of weight loss (P<.0001), adjusted for baseline level, age, and race/ethnicity.

These findings suggest that weight loss promotes increased serum 25(OH)D in overweight or obese women. Funded by Jenny Craig, Inc.