oa Relationship between plasma vitamin D level and cardiometabolic disease risk factors

Background and Objectives: Vitamin D is thought to modulate cardiometabolic disease risk through effects on an array of disease-associated pathways, such as glucose and lipid metabolism and inflammation. Although vitamin D insufficiency is thought to play a role in the susceptibility to cardiometabolic disease, the association between the two conditions is yet to be investigated in both men and women from the general population. Methods: Subjects (n= 1,928, age range 16-79 yrs) from Canada were examined. Plasma 25-hydroxyvitamin D [25(OH)D] by month of clinic visit were plotted for men and women to examine the monthly fluctuation patterns. Linear regression models adjusted for sex, waist circumference, physical activity, hormone use, and season of clinic visit examined the linear associations between 25(OH)D and cardiometabolic biomarkers [glucose, insulin, HOMA-IR, triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total:HDL-C ratio, apolipoprotein(apo)A1, apoB] and biomarkers of inflammation [C reactive protein (CRP), fibrinogen, and homocysteine]. Analyses were repeated separately for men and women. Results: Monthly variation in 25(OH)D was noted for both men and women, with mean levels fluctuating more widely throughout the year in men (50 to 80 nmol/L) than in women (60 to 75 nmol/L). Significant inverse associations with 25(OH)D were noted for insulin (β= -0.16, p=0 .003), HOMA-IR (β= -0.18, p= 0.002), triglycerides (β= -0.21, p= 0.004), total cholesterol (β= -0.31, p= 0.046), LDL-C (β= 0.09, p= 0.02), and total:HDL-C ratio (β= -0.09, p= 0.004). When the population was stratified by sex, significant inverse associations with 25(OH)D were observed for insulin (β= -0.21, p= 0.002), HOMA-IR (β= -0.24, p= 0.002), and triglycerides (β= -0.26, p= 0.01) among men, and insulin (β= 0.13, p= 0.05), HOMA-IR (β= -0.14, p= 0.03), total cholesterol (β= -0.34, p= 0.05), LDL-C (β= -0.10, p= 0.02), and total:HDL-C ratio (β= -0.10, p= 0.001) among women. Conclusions: Plasma 25(OH)D levels vary month-to-month, and fluctuate more widely in men than in women. Vitamin D may modulate multiple processes related to the cardiometabolic biomarkers and disease risk and may, thereby, play a role in disease prevention.