Serum 25-hydroxyvitamin D concentration, established and emerging cardiovascular risk factors and risk of myocardial infarction before the age of 60 years.

Objective: We examined the relationships of serum 25-hydroxyvitamin D (25(OH)D) concentration to established and emerging cardiovascular risk factors and risk of myocardial infarction (MI) in a population-based case-control study of MI before the age of 60 years.

Methods: A total of 387 survivors of a first MI and 387 sex- and age-matched controls were included. Fasting blood samples drawn three months after the MI in cases and at the same time in the matched controls were used for biochemical analyses.

Results: Serum concentrations of 25(OH)D, adjusted for seasonal variation, were lower in cases than controls (55.0 (40.0-71.0) nmol/L vs 60.5 (47.0-75.0) nmol/L; median (interquartile range); standardized odds ratio (OR) for MI with 95% confidence interval in univariable analysis: 0.80 (0.69-0.93); p = 0.003). The 25(OH)D association with MI disappeared after adjustment for established and emerging risk factors (OR: 1.01 (0.82-1.25)). Current smoking and plasma levels of proinsulin and PAI-1 activity were independently associated with 25(OH)D in controls, whereas waist circumference, plasma triglycerides, proinsulin, PAI-1 activity and cystatin C, and non-Nordic ethnicity were independently associated with 25(OH)D in patients. Serial measurements of 25(OH)D (samples drawn <4 h and 3 months after the onset of MI) in 57 patients showed no systematic differences between sampling times.

Conclusion: Vitamin D insufficiency, which is associated with a multitude of metabolic, procoagulant and inflammatory perturbations, is not independently related to premature MI. This suggests that vitamin D insufficiency either constitutes an epiphenomenon or increases the risk of MI by promoting established risk factor mechanisms that predispose to atherothrombosis.