Can vitamin D deficiency cause diabetes and cardiovascular diseases?

Present evidence and future perspectives

G. Muscogiuria, giovanna.muscogiuri at edu.rm.unicatt.it
G.P. Soricea,
R. Ajjanb,
T. Mezzaa,
S. Pilzc,
A. Priolettaa,
R. Scraggd,
S.L. Volpee,
M.D. Withamf,
A. Giaccaria
a Endocrinologia e Malattie del Metabolismo, Università Cattolica, Rome, Italy
b Division of Cardiovascular and Diabetes Research, University of Leeds, UK
c Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria
d Epidemiology & Biostatistics, School of Population Health, University of Auckland, New Zealand
e Department of Nutrition Sciences, Drexel University, Philadelphia, PA, USA
f Ageing and Health, Centre for Cardiovascular & Lung Biology, University of Dundee, UK

Received 17 August 2011. Revised 4 October 2011. Accepted 2 November 2011. Available online 20 January 2012.
Nutrition, Metabolism and Cardiovascular Diseases Jan 2012
http://dx.doi.org/10.1016/j.numecd.2011.11.001, How to Cite or Link Using DOI

Several studies have shown that vitamin D may play a role in many biochemical mechanisms in addition to bone and calcium metabolism. Recently, vitamin D has sparked widespread interest because of its involvement in the homeostasis of the cardiovascular system. Hypovitaminosis D has been associated with obesity, related to trapping in adipose tissue due to its lipophilic structure. In addition, vitamin D deficiency is associated with increased risk of cardiovascular disease (CVD) and this may be due to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which it might modulate cardiovascular risk are not fully understood.

Given this background, in this work we summarise clinical retrospective and prospective observational studies linking vitamin D levels with cardio-metabolic risk factors and vascular outcome. Moreover, we review various randomised controlled trials (RCTs) investigating the effects of vitamin D supplementation on surrogate markers of cardiovascular risk.

Considering the high prevalence of hypovitaminosis D among patients with high cardiovascular risk, vitamin D replacement therapy in this population may be warranted; however, further RCTs are urgently needed to establish when to begin vitamin D therapy, as well as to determine the dose and route and duration of administration.
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Blurry (but free!) image from the web appears to show a considerable change of risk ratio with vitamin D level

from a previous Cochrane study of 5 random controlled trials.

Figure 1. Forest plot of relative risks of coronary heart disease associated with the lowest 25 hydroxyvitamin D (25(OH)D) category compared with the highest (or reference) in cohort studies.

Adapted from: Review Manager (RevMan) Computer program. Version 5.1. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration. 2011.