Cardiovascular disorders:
Vitamin D receptors and its metabolizing enzymes are present in the whole cardiovascular system (67). The VDR knock-out mice showed severe impairments in cardiovascular system including cardiac hypertrophy (68). Many observational studies and results of meta-analyses showed vitamin D deficiency is associated with the cardiovascular disorders (69, 70, 71, 72, 73). The studies to probe the association of vitamin D deficiency with cardiovascular events in Pakistani population are very few. A study conducted in patients with first acute myocardial infarction (AMI) showed association between vitamin D deficiency and a genetic variant in the vitamin D binding protein with this event (74). However, another study conducted to evaluate the role of vitamin D and calcium deficiency with hypertension showed weak correlation of these two factors with mean, systolic and diastolic blood pressures (75).
Vitamin D deficiency was also studied with the relevance of cardio metabolic syndrome and found that it was significantly associated with hypertension in Pakistani population (76). High levels of parathyroid hormone (PTH) could be responsible for the development of hypertension (77, 78). One study conducted in Pakistani population showed that PTH levels were significantly associated with variation (R990G) of calcium sensing gene in the vitamin D deficient subjects (79). However, blood pressure was not monitored in this study.