Dyslipidaemia
While the hypothesis of a possible link between hypovitaminosis
D and CVD seems evident, data on the role of
vitamin D in regulating blood lipid concentrations (one of
the major risk factors for CVD) are still inconsistent
[17e20]. Moreover, the few intervention trials available
were not able to clearly demonstrate consistent effects of
vitamin D treatment on plasma lipids
A study specifically designed to clarify the relationship
between vitamin D status and metabolic risk factors of CVD,
in healthy individuals without diabetes, showed that serum
25(OH)D levels were inversely associated with multiple
metabolic risk factors including serum low density lipoprotein
cholesterol (LDL-C) levels [24], regardless of body
mass index (BMI), but only in male subjects. Similar results
were obtained by Chiu et al. [25] and by Carbone et al. [20]
Supplementation with calcium and vitamin D showed no
changes in lipid parameters in short-term treatment in
healthy post-menopausal women [17] and in more than 5
years of treatment in the Women’s Health Initiative [21]. By
contrast, a similar study (confounded by a concomitant
weight loss programme) found that calcium and vitamin D
supplementation resulted in significantly decreased serum
LDL-C levels [26], while a randomised controlled trial (RCT)
[21] in overweight subjects found that over 12 months of
vitamin D supplementation resulted in a significant
decrease in serum triglyceride concentrations, but not in
serum LDL-C levels. By contrast, Zittermann et al. [22]
showed in 200 overweight subjects that vitamin D supplementation
was associated with increased LDL levels but
decreased triglycerides. From all the above-reported
studies, it is evident that only large, specifically designed
RCT will be able to clarify possible effects of vitamin D on
plasma lipids.