Utilization of serum vitamin A testing and vitamin A deficiency in Korea

Vitamin A deficiency remains a clinically relevant nutritional issue, yet data on real-world testing patterns and vitamin A status in Korea are limited.

We conducted a retrospective observational study analyzing serum vitamin A (retinol) test results performed for diagnostic purposes at a large referral laboratory in Korea between 2016 and 2024. Vitamin A deficiency (< 0.70 µmol/L) and testing patterns were evaluated by age, sex, calendar year, and referring institution type, and factors associated with deficiency were examined using multivariable logistic regression; population-level prevalence was additionally assessed using weighted data from KNHANES 2016-2018.

A total of 15,042 serum vitamin A measurements from 9,608 individuals were analyzed. The overall prevalence of vitamin A deficiency was 7.6%. In the GC Labs population, vitamin A deficiency showed a U-shaped age distribution, with higher prevalence in younger age groups and in older adults, particularly those aged ≥ 80 years, who had the highest risk (adjusted odds ratio 9.52). Male sex and testing at public health centers were also independently associated with deficiency. In the KNHANES 2016-2018 population, the weighted prevalence of vitamin A deficiency was low (0.76%); however, a similar U-shaped age distribution was observed, with relatively higher prevalence in adolescents and older adults.

Although vitamin A deficiency does not represent a major public health burden in Korea, older adults and specific high-risk groups may be vulnerable. These findings provide a real-world overview of vitamin A testing practices and support targeted clinical and nutritional assessment in selected populations.