Increasing levels of vitamin D are associated with decreasing renal function, according to new study findings.
Jong Park, MD, PhD, and collaborators at Chosun University Medical School in Gwangju, Korea, studied the relationship between 25-hydroxvitamin D (25[OH]D and estimated glomerular filtration rate (eGFR) and albuminuria in 11,336 adults who participated in the 5th Korean National Health and Nutritional Examination Survey 2011–2012.
After adjusting for covariates and albumin-to-creatinine (ACR) values, patients in the 1st, 2nd, 3rd, and 4th quartiles of 25(OH)D levels had mean eGFR values of 93.4, 91.9, 90.9, and 90.2 mL/min/1.73 m2, respectively. The 1st, 2nd, 3rd, and 4th quartiles of 25(OH)D corresponded to 25(OH)D levels less than 13.15, 12.15–16.53, 16.54–20.49, and 20.50 ng/mL or greater, respectively.
The mean 25(OH)D value was highest at eGFR levels of 61–90 mL/mn/1.73 m2 and decreased significantly with decreasing eGFR levels. Patients who had an eGFR greater than 90, 61–90, 46–60, 31–45, and 30 mL/min/1.73 m2 or less had mean 25(OH)D values of 17.3, 17.6, 17.1, 16.2, and 13.8 ng/mL, respectively, Dr Park and colleagues reported in the Journal of Renal Nutrition (2016;26:360-366).
Additionally, after adjusting for covariates and eGFR, mean ACR values decreased significantly with increasing 25(OH)D quartiles. Patients in the 1st, 2nd, 3rd, and 4th quartiles had a mean ACR of 22.0, 20.4, 16.3, and 15.0 µg/mg, respectively, Dr Park’s group reported.
When the investigators stratified patients by age quartile (20–37, 38–51, 52–64 and older than 64 years), they found that mean eGFR values decreased significantly with increasing 25(OH)D in all except the over-64 group.