Vitamin D deficiency and its associated risk factors in normal adult population of Birjand, Iran

Background: Vitamin D is required for calcium absorption, bone growth, and regulation of the immune system. Geographical location determines the intensity of the solar ultraviolet (UV) light as a significant determinant of vitamin D status in the many studies. This study was conducted to determine the status of vitamin D deficiency and its associated factors in adults of Birjand city, Iran (latitude: 32.87; longitude: 59.22).

Methods: This descriptive-analytic study was performed by random stratified sampling on 400 subjects over 40 years of age in Birjand, who signed the consent form for participation. Data were collected in winter within one month from eight municipal health centers. Information regarding demographic characteristics, blood pressure, and anthropometric indices were collected, and blood samples were collected to measure 25-hydroxyvitamin D concentration.

Results: The mean serum concentration of 25-OHD was 45.4 nmol/L. Twenty-six percent of subjects had vitamin D deficiency, 45.2% had insufficiency, and 28.8% of the subjects were healthy. The results of the multiple logistic regression showed that age (OR: 0.92, 95% CI = 0.89-0.96) and serum calcium concentration (OR: 0.52, 95% CI = 0.28-0.94) had a significant correlation with 25-OHD deficiency.

Conclusion: A high percentage of adults in the city of Birjand are suffering from vitamin D deficiency, which implies a need for extensive training and food enrichment programs, promoting healthy lifestyles, and exercise and walking.