The Sunshine Paradox: Unraveling Risk Factors for Low Vitamin D Status Among Non-Pregnant Women in Lebanon

Background/Objectives: Vitamin D-crucial for bone health, immune function, and hormone regulation-is deficient worldwide, affecting around half the population, particularly women. The study aims to determine the prevalence and risk factors of vitamin D deficiency and hypovitaminosis D in non-pregnant women in Lebanon. Methods: A national cross-sectional survey sampled households across Lebanon, covering 2803 non-pregnant women aged 15 to 49. Demographic information and dietary habits were collected, and anthropometric measurements and serum analyses, including 25-hydroxyvitamin D (25(OH)D) concentrations, were conducted. Multivariable Poisson regressions were constructed to calculate the adjusted prevalence ratio (aPR) for vitamin D deficiency and hypovitaminosis D of variables. Results: The prevalence of vitamin D deficiency (<30 nmol/L) among non-pregnant women in Lebanon was 37.9%, while 69.2% had hypovitaminosis D (<50 nmol/L). Wearing a veil (hijab) was identified as the most significant risk factor for both vitamin D deficiency (aPR = 3.76) and hypovitaminosis D (aPR = 1.47). Additionally, olive skin and dark skin were both associated with an increased prevalence of vitamin D deficiency (olive skin: aPR = 1.14; dark skin: aPR = 1.28), while only dark skin color was associated with hypovitaminosis D (aPR = 1.10). In contrast, protective factors against vitamin D deficiency and hypovitaminosis D included daily sun exposure exceeding one hour (aPR = 0.83-0.91) and vitamin D supplementation (aPR = 0.30-0.55). Anemia, folate deficiency, and vitamin B12 deficiency were significantly associated with a higher prevalence of vitamin D deficiency, hypovitaminosis D, or both. BMI was not significantly associated with vitamin D deficiency; however, women with underweight (aPR = 1.13) and obesity (aPR = 1.12) exhibited a higher prevalence of hypovitaminosis D. Conclusions: Vitamin D deficiency and hypovitaminosis D affect a significant portion of non-pregnant women in Lebanon, with veiling (hijab wearing), limited sun exposure, and lack of supplementation as primary risk factors. Future work should focus on tailoring recommendations for vitamin D supplementation, sun exposure, and food fortification to effectively address the diverse risk factors in the population.