A recent study published by the North American Journal of Medical Sciences showed that vitamin D status is inversely related to chronic stable angina.
Coronary artery disease (CAD) is the most common form of heart disease, responsible for about one in every five deaths in developing countries. In about 50% of individuals, chronic stable angina is the first indicator of CAD. Chronic stable angina results from poor blood flow to the heart, causing chest pain or discomfort during exercise or times of stress.
Vitamin D receptors are located in the cardiac cells, as well as vascular endothelial cells, indicating that vitamin D plays an important role in cardiac function. Research continues to support this theory, with evidence showing that vitamin D may improve endothelial function and decrease inflammation in cases of heart disease.
The population in Northern India experiences an increased rate of vitamin D deficiency. Additionally, due to the relatively limited resources in this region, preventative action is crucial in decreasing the risk of cardiovascular complications. With the limited number of studies examining the relationship between vitamin D and CAD in Northern India to date, researchers recently aimed to determine if vitamin D may act as an independent risk factor for the development of chronic stable angina.
The study was conducted at the Sher-i-Kashmir Institute of Medical Sciences (SKIMS). It included a total of 100 patients with chronic stable angina and 100 matched controls were included in the study. Those who had a history of cancer in the last 5 years, who supplemented with vitamin D or calcium or who had parathyroid disease were excluded from the study.
The following diagnostic tools were utilized:
- A comprehensive medical history was gathered on all patients, including blood work.
- All patients with angina received a 12 LEAD ECG, a standard tool in the diagnoses of CAD, along with a chest x-ray.
- For those suspected to have chronic stable angina and were fit for exercise, a treadmill test was performed (TMT). A positive TMT indicates an abnormal heart rate, blood pressure and breathing while exercise.
- Coronary angiography (CAG), in which dye is injected into the coronary arteries to look for blockage, was done on all patients with chronic stable angina and presented a positive TMT.
Here is what the researchers found:
- A total of 75% of those with chronic stable angina were vitamin D deficient (<20ng/ml), while only 10% of healthy controls were deficient.
- The difference in 25(OH)D levels were significantly different between the two groups (p <0001), with the mean vitamin D levels of cases and controls at 15.5 ng/ml and 40.9 ng/ml, respectively.
- Disease severity was not significantly related to vitamin D status.
- Increased age was associated with lower vitamin D levels (p = 0.027).
The researchers concluded,
“Our study indicates a correlation between vitamin D deficiency and chronic stable angina. Low levels may be an independent, potentially modifiable cardiovascular risk factor.”
These findings are consistent with past research that has evaluated the relationship between vitamin D status and coronary angiography, showing that 80% of those with an abnormal CAG were vitamin D deficient and only 7% were within the healthy range. However, due to the current study’s observational design, causation cannot be proven. Additionally, the limited number of vitamin D deficient controls, despite the elevated prevalence of vitamin D deficiency in the region, indicates that the study may have been subject to selection bias. Therefore, clinical trials are needed in order to determine if vitamin D may prevent or treat chronic stable angina.
Sturges, M. & Cannell, JJ. Vitamin D status linked to chronic stable angina. The Vitamin D Council Blog & Newsletter, 2016.