Determinants of plasma vitamin D levels in patients with acute coronary syndromes

Background: Vitamin D is implicated in various biological functions ranging from cellular proliferation to immunity. Vitamin D deficiency is associated with an increased risk of several diseases including coronary atherosclerosis.

Materials and methods: We measured plasma 25(OH)D3 level in 224 patients with acute coronary syndromes (ACS) and 209 control individuals by ELISA. We genotyped the study populations for 11 single nucleotide polymorphisms (SNPs) in seven genes involved in vitamin D biosynthesis and metabolism by 5' nuclease assays.

Results: The mean and median plasma 25(OH)D3 levels were not significantly different between patients with ACS and controls (median: 22·06 vs. 22·24 ng mL(-1) , respectively, P = 0·618). Plasma 25(OH)D3 level was < 20 ng mL(-1) in 175/433 (40%) and < 30 ng mL(-1) in 333/433 (77%) participants. Only four individuals had plasma 25(OH)D3 levels of above 60 ng mL(-1) . African-American and Hispanic populations, women and those with diabetes mellitus had significantly lower plasma 25(OH)D3 levels. In multivariable regression analysis, age, sex, diabetes mellitus, body weight, rs2762933 (CYP24A1) and rs6055987 (PLCB1) SNPs were independent predictors of plasma 25(OH)D3 level in the Caucasian population.

Conclusions: We found no difference in mean plasma vitamin D levels between patients with ACS and controls. Differences in population characteristics between the two study groups including medications use and the lack of data on vitamin D, calcium and multivitamin supplements intake as well as the relatively small sample size of the populations could confound the results. Ethnic background, sex, age, body weight and SNPs in CYP24A1 and PLCB1 were independent determinants of plasma vitamin D levels.