Abstract
Coronary artery disease and vitamin D deficiency are both widespread conditions with a high incidence worldwide. Coronary artery disease is a complex illness with variable manifestation and pathogenesis. It often involves the development of atherosclerosis, and it frequently has serious or even fatal consequences for the patient. Vitamin D receptor expression is found in many tissues throughout the body, which results in a broad effect of the vitamin. Studies have found correlations between vitamin D deficiency and the development of coronary artery disease as well as other cardiovascular diseases, such as hypertension. This review will discuss randomized controlled trials conducted from 2020 forward, aiming to elucidate whether vitamin D supplements have the potential to be used as an add-on treatment for coronary artery disease. The randomized controlled trials all used vitamin D as intervention and tested a population suffering from coronary artery disease or the risk of developing it. Even though animal studies found evidence that vitamin D can regulate inflammation, lipid profile, foam cell formation, vessel reactivity, and blood pressure, which are all mediators in the development of atherosclerosis, the results from the randomized controlled trials were ambiguous. The general older population did not seem to benefit from the treatment, but different subgroups such as patients with type 2 diabetes and patients with more developed coronary artery disease exhibited some positive effects from the treatment. Furthermore, vitamin D showed cardioprotective effects following coronary artery bypass surgery, which make it a possible add-on treatment before invasive coronary intervention. The question in focus still needs further research and a more focused approach on subgroups that may benefit from treatment.