Objective: Vitamin D deficiency is a global health problem. The present study aimed to investigate the vitamin D status and its associated factors in rural subjects in Nakhon Si Thammarat province, Southern Thailand.

Materials and Methods: A cross-sectional study of 839 healthy volunteers, aged 18 to 94 years in Southern Thailand was performed. Demographic variables including age, body mass index [BMI], gender, area of residence, religion, the use of multivitamin supplements, sunscreen used, and behavioral lifestyles were recorded. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured by electrochemiluminescent immunoassay.

Results: The prevalence of vitamin D deficiency and insufficiency were 6.91% and 43.74%, respectively. Women showed a significantly higher in vitamin D deficiency than men (8.05% versus 2.38%, p<0.001). Logistic regression analysis demonstrated that vitamin D deficiency and/or hypovitaminosis D were associated with being Muslim, women, living inland, alcohol consumption, obesity, the use of sunscreen, and advancing age.

Conclusion: The prevalence of vitamin D insufficiency is high in rural subjects in Nakhon Si Thammarat. The lifestyle modification such as increasing sun exposure, increasing outdoor activity, increasing vitamin D intake, avoiding alcohol intake, and reducing weight, should be implemented to prevent vitamin D deficiency and hypovitaminosis D.

Keywords: Vitamin D deficiency, Vitamin D insufficiency, Risk factors, Prevalence