25-hydroxyvitamin D Levels and chronic kidney disease in the AusDiab (Australian Diabetes, Obesity and Lifestyle) study
1 Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, 3168, Victoria, Australia
2 Monash University, Wellington Rd, Clayton, 3168, Victoria, Australia
3 Baker IDI Heart and Diabetes Institute, 75 Commerical Rd, Melbourne, 3004, Victoria, Australia
4 School of Exercise and Nutrition Sciences, Deakin University, Burwood Hwy, Burwood, 3125, Victoria, Australia
5 Centre de recherche du CHUQ, 2325, rue de l'Université, Québec (Québec), Quebec G1V, 0A6, Canada
6 Melbourne Pathology, 103 Victoria Parade, Collingwood, 3066, Victoria, Australia
7 NorthWest Academic Centre, University of Melbourne, Western Health, 176 Furlong Road, St Albans, 3021, Victoria, Australia
8 Department of Nephrology and Transplantation, Royal Prince Alfred Hospital, Missenden Road, Camperdown, 2005, NSW, Australia
9 Sydney Medical School, University of Sydney, Sydney, 2006, NSW, Australia
BMC Nephrology 2012, 13:55 doi:10.1186/1471-2369-13-55Published: 3 July 2012
Low 25-hydroxy vitamin D (25(OH)D) levels have been associated with an increased risk of albuminuria, however an association with glomerular filtration rate (GFR) is not clear. We explored the relationship between 25(OH)D levels and prevalent chronic kidney disease (CKD), albuminuria and impaired GFR, in a national, population-based cohort of Australian adults (AusDiab Study).
10,732 adults ≥25 years of age participating in the baseline survey of the AusDiab study (1999–2000) were included. The GFR was estimated using an enzymatic creatinine assay and the CKD-EPI equation, with CKD defined as eGFR <60 ml/min/1.73 m2. Albuminuria was defined as a spot urine albumin to creatinine ratio (ACR) of ≥2.5 mg/mmol for men and ≥3.5 for women. Serum 25(OH)D levels of <50 nmol/L were considered vitamin D deficient. The associations between 25(OH)D level, albuminuria and impaired eGFR were estimated using multivariate regression models.
30.7% of the study population had a 25(OH)D level <50 nmol/L (95% CI 25.6-35.8). 25(OH)D deficiency was significantly associated with an impaired eGFR in the univariate model (OR 1.52, 95% CI 1.07-2.17), but not in the multivariate model (OR 0.95, 95% CI 0.67-1.35). 25(OH)D deficiency was significantly associated with albuminuria in the univariate (OR 2.05, 95% CI 1.58-2.67) and multivariate models (OR 1.54, 95% CI 1.14-2.07).
Vitamin D deficiency is common in this population, and 25(OH)D levels of <50 nmol/L were independently associated with albuminuria, but not with impaired eGFR. These associations warrant further exploration in prospective and interventional studies.