Abstract
Background:
Vitamin D deficiency estimated to affect 50% of worldwide population of different civilizations and age groups.

Aim:
This retrospective cross-sectional study aimed to determine the prevalence and associated risk factors of vitamin D deficiency among residents of the Aljabal Algharbi region in Libya.

Methods:
A total of 657 laboratory test results were analyzed from patients in six cities: Gharian, Alasabaa, Alzintan, Jadu, Nalut, and Yafrin, covering the period from 2021 to 2024. Patient demographic data, including age and gender, were collected. According to clinical records, all tests were conducted using the Elecsys Vitamin D III Total kit for quantifying serum 25-hydroxyvitamin D [25(OH)D] levels. Vitamin D deficiency was defined as a serum 25(OH)D level of <30 ng/mL, while levels between 30–100 ng/mL were considered sufficient.

Results:
Overall, 506 patients (77%) were found to be vitamin D deficient. The prevalence was significantly higher in females (80%, 366/460) than in males (71%, 140/197) (p < 0.05). Among age groups, the highest deficiency rate (85%) was observed in individuals aged 31–50 years (p < 0.05), while the lowest was recorded in children aged 0-5 years. Multivariate analysis revealed that females (OR: 1.162, 95% CI: 1.015–1.330) and individuals aged 31–50 years (OR: 3.004, 95% CI: 1.197–7.537) were at significantly higher risk of deficiency.

Conclusion:
This study highlights a critical need for targeted public health interventions in the region. A coordinated effort involving healthcare providers, policymakers, and communities is essential to improve vitamin D status and mitigate the associated health risks.

Key words: Retrospective cross-sectional; Vitamin D deficiency; Risk factors; Epidemiology; Aljabal Algharbi region; Libya.