Vitamin D and cardiometabolic health: a review of the evidence

Abstract

The cardiometabolic syndrome (MetS) is a clustering of related metabolic abnormalities including abdominal adiposity, insulin resistance, hypertension, dyslipidaemia and increased inflammatory and thrombotic markers, which is linked to increased risk of type 2 diabetes, CVD and overall mortality. Several cross-sectional and prospective studies have shown an association between low vitamin D status, as indicated by concentrations of serum 25-hydroxyvitamin D (s25(OH)D), and increased prevalence of the MetS and individual CVD risk factors. These epidemiological observations are supported by mechanistic studies but experimental data are limited. The available data from intervention studies are largely confounded as most vitamin D supplementation trials were mainly carried out to explore the role of Ca in CVD and include Ca in the treatment arms. Inadequate consideration of seasonal effects on s25(OH)D concentrations is also a common design flaw in most studies. Further complications arise from shared risk factors such as adiposity and ageing, which predispose individuals to exhibit both a more pronounced risk profile and relatively lower s25(OH)D concentrations. In conclusion, while epidemiological associations are promising and a rationale for low vitamin D status as a potentially modifiable risk factor for CVD is supported by mechanistic data, suitable experimental data from appropriately designed trials are just beginning to emerge. As yet, this body of literature is too immature to draw firm conclusions on the role of vitamin D in CVD prevention. Carefully controlled vitamin D trials in well-described population groups using intervention doses that are titrated against target s25(OH)D concentrations could yield potentially valuable outcomes that may have a positive impact on CVD risk modification.

Low 25(OH)D3 levels are associated with total adiposity, metabolic syndrome, and hypertension in Caucasian children and adolescents

“…Vitamin D status has been associated with dyslipidemia in some instances, but the literature is conflicting and the evidence base is still gathered (1). Vitamin D is thought to be essential for maintaining adequate levels of apolipoprotein A-1 (the main component of HDL).…”

“…Several cross-sectional and prospective studies have shown an association between low vitamin D status, as indicated by concentrations of serum 25-hydroxyvitamin D (25(OH)D), and increased prevalence of the metabolic syndrome (MetS) and individual cardiovascular disease (CVD) risk factors (1). A recent systematic review and meta-analysis, using data from eight crosssectional studies, showed that the prevalence of the MetS was reduced by w50% (odds ratio (OR), 0.49; 95% confidence intervals (CIs), 0.38-0.64)) for those with high 25(OH)D concentration (2).…”

A review of vitamin D status and CVD

“…The mechanistic evidence on the effect of vitamin D status on myocardial diseases and CVD risk factors has been expertly reviewed elsewhere (6,7,(18)(19)(20)(21) . To aid the reader, these will only be briefly highlighted here, and interested readers are referred to these comprehensive reviews for detailed explanations.…”

“…These have been reviewed elsewhere in detail (6,7,(18)(19)(20)(21) . In relation to the latter two, recent data on genetic variants in vitamin D metabolism-related genes and those of the BMI (22)(23)(24) , seem to suggest that obesity contributes to vitamin D deficiency and not that vitamin D deficiency causes obesity.…”

“…Epidemiological studies of different designs have reported reduced serum/plasma 25(OH)D concentrations and increased risk of MI and early mortality due to CVD (for reviews, see (6,7,(18)(19)(20)(21)28,29) ). In particular, these include at least twenty population-based follow-up studies of the association of 25(OH)D and cardiovascular events and mortality (details of these studies have been provided recently in a meta-analysis by Wang et al (30) ).…”