Serum 25-hydroxyvitamin D relationships to carotid intima-media thickness (cIMT) and cIMT progression in a European high-risk population

Purpose: Vitamin D deficiency has been implicated in cardiovascular disease (CVD) as well as in promoting multiple cardiovascular risk factors such as obesity, dyslipoproteinemia, type-2 diabetes and hypertension. We investigated the relationships of serum 25-hydroxyvitamin D (25(OH)D) concentration to established and emerging cardiovascular risk indicators, baseline cIMT and cIMT progression in the IMPROVE study. Methods: IMPROVE is a European, multicentre, longitudinal cohort study, which enrolled individuals aged 54 to 80 years with at least three cardiovascular risk factors and no history of CVD from 7 centers in Finland, Sweden, the Netherlands, France, and Italy. Participants underwent carotid ultrasound examination at baseline, month 15 and month 30. Blood samples, clinical data and information about life style factors collected at baseline from a total 3430 subjects were used in the present substudy of 25(OH)D. Results: Serum 25(OH)D levels were positively correlated with latitude. Subjects having deficient levels of vitamin D (defined as serum 25(OH)D below 25 nmol/L) were more often women, smokers and diabetics, were more obese, had higher blood pressure, triglyceride, blood glucose and CRP levels, had lower HDL and were less physically active. Waist circumference, diastolic blood pressure, triglycerides, HDL, LDL, current smoking and high physical activity showed significant and independent associations with 25(OH)D in multiple robust regression analyses. Overall, there were no consistent independent relationships between 25(OH)D and segment-specific or composite IMT measures (baseline or progression) when age, sex, latitude and clinical and biochemical risk indicators (the latter selected by best subset analysis) were included in multivariable linear regression models. Conclusions: Levels of 25(OH)D differed across Europe, showed multiple associations with established and emerging cardiovascular risk factors but were not independently related to cIMT or cIMT progression. This argues against an independent causal role of vitamin D in early subclinical atherosclerosis in high-risk individuals