Vitamin D Status in North Batinah, Oman: Prevalence and Temporal Trends (2018-2022)

Abstract

Background: Vitamin D plays a critical role in skeletal health and has important functions in immune regulation and chronic disease prevention. Despite abundant sunlight in the Middle East, vitamin D deficiency and insufficiency remain widely reported, with limited population-based data available from Oman. This study aimed to evaluate the prevalence and temporal trends of vitamin D status in North Batinah, Oman, and to identify demographic groups at increased risk of insufficiency and deficiency. Methods: A retrospective cross-sectional study was conducted using laboratory and clinical data from Suhar Hospital, the central referral laboratory in North Batinah. The study included 3,081 individuals of all ages who underwent serum 25-hydroxyvitamin D testing between January 2018 and November 2022. Vitamin D status was classified as deficient (<30 nmol/L), insufficient (30–50 nmol/L), or sufficient (>50 nmol/L). Demographic variables and vitamin D levels were analyzed, and temporal trends were assessed over the five-year period. Results: The overall mean vitamin D level was 82.5 ± 28.0 nmol/L. Vitamin D sufficiency was observed in 88.2% of adults and 89.0% of the pediatric population, while deficiency was rare (<1%). Insufficiency was more prevalent among females, particularly those aged 18–38 years (14.9%), and among adolescents aged 10–15 years (15.7%). Males had significantly higher vitamin D levels than females (p < 0.001). Temporal analysis demonstrated a significant decline in sufficiency from 93.1% in 2018 to 79.9% in 2021, followed by recovery to 91.0% in 2022 (p < 0.001), corresponding with reduced outdoor activity during the coronavirus pandemic period. Conclusion: Vitamin D sufficiency was high in this population, contrasting with commonly reported regional trends. However, insufficiency remains a clinically relevant concern, particularly among women and adolescents. These findings support a shift toward targeted, risk-based screening and highlight the importance of sustained public health strategies to maintain optimal vitamin D status.