Vitamin D deficiency among Ethiopian adults: current evidence, determinants, and policy implications.

Vitamin D deficiency, commonly defined as a serum 25-hydroxyvitamin D [25(OH)D] level below 20 ng/mL (50 nmol/L), is a hidden but potentially high-impact public health problem in Ethiopian adults, despite the country's abundant year-round sunlight. Emerging studies indicate that certain populations, including pregnant women, patients with tuberculosis or HIV, and urban residents, experience high rates of deficiency, yet nationally representative data are virtually nonexistent. The lack of robust prevalence data, combined with limited laboratory capacity and low clinical awareness, has left this issue largely invisible in Ethiopia's health policy agenda. This narrative review synthesizes the existing evidence on vitamin D deficiency among Ethiopian adults through a literature search of PubMed/PMC, Web of Science, Google Scholar, and African Journals Online (AJOL). It identifies key determinants, including reduced sun exposure, dietary insufficiency, and dark skin pigmentation, and examines potential health consequences, such as impaired bone health, increased fracture risk, and altered immune and metabolic function. Drawing on successful fortification and supplementation programs from other sub-Saharan African countries, the review also outlines feasible, context-specific strategies for Ethiopia, including staple food fortification, targeted supplementation for high-risk groups, and public health campaigns promoting safe sun exposure. The review also highlights important evidence gaps, particularly the need for population-based surveys, standardized vitamin D assays, and longitudinal studies to better define the burden of deficiency and inform national policy. These findings provide an evidence-informed foundation for future research, clinical practice, and public health planning in Ethiopia.