The association between the serum 25-hydroxyvitamin D level and cardiovascular events in individuals with and without metabolic syndrome

BACKGROUND: Previous studies revealed that the level of 25-hydroxyvitamin D [25(OH)D] could be consider as one the risk factors for the occurrence of cardiovascular diseases (CVDs). This study aimed to evaluate the relationship between serum 25(OH)D level and CVD events in individuals with and without metabolic syndrome (MetS) in an Iranian population. METHODS: In this nested case-control study conducted as a part of the Isfahan Cohort Study (ISC), 55 patients with CVD events were selected as case group, and 55 sex- and age-matched individuals without CVD events as control group. These participants were divided into the two main groups based on the presence of MetS at baseline. RESULTS: The level of 25(OH)D in individuals with and without MetS was significantly lower among patients with CVD compared to those without CVD events at the baseline of study and after the follow-up (P = 0.036 and P = 0.039, respectively). The level of 25(OH)D significantly decreased risk of incidence of CVD events in individuals without MetS after adjusting for age, sex, nutrition, and exposure to sunlight [0.19 (0.05-0.73); P = 0.016]. There was not any significant relationship between the amount of 25(OH)D at the baseline and CVD events in individuals with MetS. CONCLUSION: In individuals with MetS, the level of 25(OH)D is not related to CVD events; as MetS directly influence the pathophysiology of mechanisms which are responsible for CVD events, and maybe this effect obscure the effect of 25(OH)D.