Very low vitamin D levels linked to asymptomatic CAD in high-risk patients
MedWire News: Study results show that very low levels of vitamin D are associated with subclinical coronary artery disease (CAD) in patients with Type 2 diabetes.
Christel Joergensen (Steno Diabetes Center, Gentofte, Denmark) presented the results at the European Association for the Study of Diabetes 46th annual meeting in Stockholm, Sweden.
Joergensen reported results from a cross-sectional study of 200 Danish patients with Type 2 diabetes and micro- or macroalbuminuria who did not have clinical signs of CAD. The patients were being treated with hypoglycemic, antihypertensive, and lipid-lowering medication.
The team measured vitamin D levels using high-performance liquid chromatography or tandem mass spectrometry. Severe vitamin D deficiency was defined as a level of plasma 25-hydroxy-vitamin D below 12.5 nmol/l.
Although admitting that the level chosen was unusually low, Joergensen explained: "We chose the level for severe vitamin D deficiency according to national guidelines just published in Denmark this year... and also the test that we used when analyzing our blood samples defined severe vitamin D deficiency as a level below 12.5 nmol/l."
Low levels of vitamin D are highly prevalent worldwide and have previously been linked with Type 2 diabetes and other cardiometabolic disorders. They have also been shown to predict cardiovascular (CV) mortality in patients with Type 2 diabetes.
In this study, a total of 133 patients with a coronary calcium score (CCS) above 400 and an N-terminal precursor of brain natriuretic peptide (NT-proBNP) level above 45.2 ng/l were considered to be at high risk for CAD, whereas those with lower levels were considered as low risk (n=67). The patients underwent further examination using one or a combination of the following: myocardial perfusion imaging (MPI; n=109), CT angiography (CTA; n=20) and coronary angiography (CAG; n=86).
The participants had a median vitamin D level of 36.9 nmol/l, and 19 (9.5%) patients had severe vitamin D deficiency. Of these, 14 (11.0%) were at high and five (8.0%) at low CAD risk.
Overall, 70 (35%) patients had CAD demonstrated by CAG and/or MPI. Of those with vitamin D levels below 12.5 nmol/l, 53% had CAD compared with only 33% of those with higher levels.
Following adjustment for age, gender, total cholesterol, plasma creatinine, blood pressure, vibratory perception threshold, heart rate variability, and NT-proBNP, the risk for asymptomatic CAD was increased 2.8-fold in diabetics with severe vitamin D deficiency compared with those with normal levels.
In addition, those with severe vitamin D deficiency were a significant 4.9-fold more likely to have a CCS above 400 than were individuals with higher vitamin levels.
Although the link between CAD and a high CCS and severe vitamin D deficiency remained significant after adjusting for all possible confounders, Joergensen and colleagues found that there were no significant associations with either moderate vitamin D deficiency (12.5-25.0 nmol/l) or vitamin D insufficiency (25.0-50.0 nmol/l).
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By Helen Albert