Serum 1,25-dihydroxyvitamin d and the development of kidney dysfunction in a Japanese community: The hisayama study

Background: Recent evidence indicates that vitamin D deficiency is associated with an increased risk of renal impairment, but studies addressing the influence of vitamin D deficiency on the development of chronic kidney disease (CKD) in the general Asian population have been few. Methods and Results: A total of 2,417 community-dwelling individuals without CKD stage 3-5 aged ≥40 years were followed for 5 years (mean age, 60 years; women, 59.1%). The cumulative incidence of CKD stage 3-5, defined as estimated glomerular filtration rate (eGFR) <60 ml · min^-1 · 1.73 m^-2, and the rate of decline in eGFR according to quartile of serum 1,25-dihydroxyvitamin D (1,25(OH)₂D), were estimated. During follow-up, 378 subjects experienced CKD stage 3-5. The age- and sex-adjusted incidence of CKD stage 3-5 increased significantly with decreasing serum 1,25(OH)₂D (P for trend <0.001). Compared with the highest quartile, the multivariate-adjusted odds ratio for the development of CKD stage 3-5 was 1.90 in the lowest quartile and 1.74 in the second lowest quartile, after adjusting for confounding factors. Additionally, lower serum 1,25(OH)₂D was significantly associated with a greater change in eGFR 0.10ml · min^-1 · 1.73m^-2 · year^-1 per 10-pg/ml decrement in serum 1,25(OH)₂D). Conclusions: Lower serum 1,25(OH)₂D is a significant risk factor for the development of CKD stage 3-5 in the general Asian population.