Effect of Milk Intake and Calcium-Vitamin D Supplementation on Serum Vitamin D Status

Vitamin D is important for health and disease. Milk is a good natural source of it, and calcium-vitamin D supplements are widely available over-the-counter and prescribed in clinical practice. But the effect of milk intake and calcium-vitamin D supplementation on serum vitamin D status is not known. This cross-sectional study was done to see the relationship between vitamin D status and milk intake or oral calcium-vitamin D supplementation using a structured questionnaire and carried out in a private consultation centre of Dhaka city, the capital of Bangladesh from July 2017 to March 2018. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by radioimmunoassay. Out of 259 patients, 64.1% had vitamin D deficiency defined as serum 25(OH)D level <20ng/mL. Sixty one percent of those who had serum 25(OH)D level <20ng/mL did not take milk or milk products, while 53.0% of those having 25(OH)D level ≥20ng/mL did not take milk. Approximately 89.0% of those who had serum 25(OH)D level <20ng/mL did not take oral calcium-vitamin D, whereas 72.0% of those having 25(OH)D level ≥20ng/mL did not take oral calcium-vitamin D (p=0.001). In the multiple logistic regression analysis, there were significantly increased odds of vitamin D deficiency for females as compared to males [odds ratio (OR) 2.48, 95% confidence interval (CI) 1.34-4.56] and not taking oral vitamin D as compared to taking oral vitamin D (OR 3.56, 95% CI 1.74-7.28). Vitamin D deficiency is widely prevalent. Lack of milk intake and calcium-vitamin D supplementation are more commonly associated with serum vitamin D deficiency, and calcium-vitamin D supplementation is specially important in females.