Vitamin D deficiency in Sri Lankan adults: A scoping review

Background: Vitamin D deficiency (VDD) is a major global public health problem. Sri Lanka, a tropical island nation located between 6–9°N latitude and receiving year-round ultraviolet B solar radiation, paradoxically has a high burden of VDD, driven by sun-avoidance behaviour, low dietary intake of vitamin D-rich foods, and the absence of national food fortification or supplementation policies. Objectives: To map published data on vitamin D status in Sri Lankan adults, describe the prevalence, determinants, and reported health associations of VDD, compare findings with regional and global data, and identify evidence gaps and locally grounded public health priorities.
Methods: A scoping review was conducted following the Arksey and O’Malley framework, using PubMed, Google Scholar, and the Sri Lanka Journals Online database. Studies reporting serum 25-hydroxy vitamin D [25(OH)D] concentrations in Sri Lankan populations were included. Regional and global systematic reviews and meta-analyses were used for comparative analysis. Consistent with scoping methodology, studies were charted descriptively without formal quality appraisal or quantitative synthesis.
Results: Reported vitamin D inadequacy ranges from 57.6% among premenopausal women to 90.2% in an urban cohort in Colombo. The most rigorous population-based study found VDD (<50 nmol/L) in 67.6% of adults in Colombo, with women more affected than men (72.6% vs 61.7%). Key determinants included sun avoidance, Fitzpatrick skin types IV–V, low dietary vitamin D intake, and obesity. Sri Lanka reports the lowest pooled VDD prevalence (48%) in South Asia but remains highly deficient in urban settings. Countries with mandatory food fortification achieve substantially lower deficiency burdens.
Conclusions: VDD is highly prevalent in urban Sri Lanka, particularly among women and working-age adults. Based on the available evidence, population-level measures, including mandatory fortification of staple foods, promotion of safe sun exposure, public education, and a national surveillance strategy, are priorities in Sri Lanka.