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.

Influence of gender on arrhythmia characteristics and outcome in the Multicenter UnSustained Tachycardia Trial.

INTRODUCTION: Previous studies have demonstrated gender differences in risk of sudden death in patients with ischemic heart disease. The Multicenter UnSustained Tachycardia Trial (MUSTT) evaluated the ability of therapy guided by electrophysiologic (EP) testing to reduce mortality in patients with coronary disease, ejection fraction < or =40%, and spontaneous nonsustained ventricular tachycardia. METHODS AND RESULTS: We analyzed the influence of gender on results of EP testing and outcome of patients enrolled in MUSTT. Women made up 14% of the overall MUSTT population and were less likely than men to have inducible sustained randomizable ventricular arrhythmias (24% vs 36%, P < 0.001). Baseline characteristics differed between men and women. In randomized patients, women were older, more likely to have had an infarction within 6 months, more likely to have a history of heart failure, and more likely to have recent angina prior to enrollment than men (P < 0.05). In the EP-guided therapy group, there was no difference in implantable cardioverter defibrillator implantation rate in men and women (45% vs 53%, P = 0.38). There also were no significant gender influences on risk of arrhythmic death or cardiac arrest (2-year event rate 9% in women and 12% in men, adjusted hazard ratio 0.88) or overall mortality (2-year event rate 32% in women vs 21% in men, adjusted hazard ratio 1.51). CONCLUSION: The outcome and benefit of EP-guided therapy in this trial did not appear to be influenced by gender. However, due to the small numbers of women in the trial, small differences in outcome may not be apparent. Plans for future primary prevention trials should include careful risk stratification of women who less often have inducible sustained ventricular arrhythmias and better left ventricular function despite more frequent heart failure.