Albuminuria, Vitamin D Linked
Decreasing levels of vitamin D are associated with increases in the prevalence in albuminuria, according to an epidemiologic study.
Ian H. de Boer, MD, MS, of the
All underwent measurement of serum 25-hydroxyvitamin D and urine albumin and creatinine. Circulating 25-hydroxyvitamin D levels reflect total intake of vitamin D from dietary and cutaneous sources, Dr. Boer's team noted. Subjects were divided into vitamin D quartiles: 3.5-17.6, 17.7-24.1, 24.2-32.0, and 32.0-97.6 ng/mL (reference).
The study population had a mean 25-hydroxyvitamin D level of 29.5 ng/mL and an overall prevalence of albuminuria of 11.6%. The prevalence of micro- and macroalbuminuria was 10.6% and 1.0%, respectively.
With decreasing quartiles of vitamin D level, the prevalence of albuminuria—either micro- or macroalbuminuria—was 8.9%, 11.5%, 13.7%, and 15.8%, the researchers reported in the American Journal of Kidney Diseases (2007;50:69-77). Each quartile of decreasing vitamin D level was associated with a 4.8% greater mean ACR. The researchers defined albuminuria as a urine albumin-creatinine ratio (ACR) of 25-2,999 mg/g for women and 17 to 2,999 mg/g for men.
Compared with reference vitamin D levels, levels of 24.2-32.0, 17.7-24.1, and 3.5-17.6 ng/mL were associated with a 12%, 22%, and 31% increased risk of albuminuria, respectively, after adjusting for age, sex, race and ethnicity, region of the United States, season, smoking status, BMI, estimated glomerular filtration rate (GFR), BP, and diabetes.