Association between Vitamin A and Anemia in Chinese Children: A Matched Case-Control Study
Year: 2026
Type: article
Study design: Observational Study
Abstract: Background Vitamin A plays an important role in the development of anemia, providing a new perspective on improving anemia. Objective To investigate the dose-response relationship between serum vitamin A and anemia risk, and evaluate its clinical applicability with adjustment for covariates. Methods A 1:3 matched case-control study (202 cases, 606 controls) was conducted, matching for sex and age (±2 years). Assess matching balance using the standardized mean difference (SMD). Anemia was defined according to WHO criteria. Unconditional logistic regression was used to assess the effect of vitamin A after adjusting for confounders. Variable adjustment was informed by a directed acyclic graph (DAG), with the primary model adjusting for age, sex, body mass index(BMI), and serum zinc(Zn). A restricted cubic spline (RCS) was applied to analyze the dose-response relationship. Subgroup analysis and interaction tests were used to examine the association across sexes. Model discrimination was evaluated using the receiver operating characteristic curve(ROC) and its area under the curve (AUC). Model calibration was evaluated using calibration plots, the Hosmer-Lemeshow test, and the Brier score. Results The case group exhibited significantly lower levels of BMI, vitamin D, vitamin A, total cholesterol, zinc, and serum ferritin (all P < 0.05). After adjusting for age, sex, BMI, and Zn, each 0.1 μg/mL increase in serum vitamin A was associated with a 27% reduction in anemia risk (OR = 0.73, 95%CI: 0.62-0.87, P <0.001). RCS analysis confirmed a linear dose-response relationship ( P for nonlinearity=0.922). Sex-stratified analysis using unconditional logistic regression suggested a numerically stronger association in males (OR=0.55, 95%CI: 0.38-0.78, P <0.001) than in females (OR=0.82, 95%CI: 0.67-1.00, P =0.053); “sex x vitamin A” interaction was statistically significant ( P =0.019). The prediction model including vitamin A improved AUC to 0.63 (ΔAUC=0.11, P <0.001) and demonstrated good calibration (Brier score=0.180; Hosmer-Lemeshow P =0.636). Conclusions Serum vitamin A demonstrates a significant, independent, and linear inverse association with anemia risk in children and adolescents. This association was more pronounced in males, indicating a potential role for vitamin A in sex-specific anemia prevention strategies. Statement of Significance This study quantifies a linear inverse dose-response relationship between serum vitamin A and anemia risk in Chinese children, providing evidence that the association spans the physiological range beyond clinical deficiency. It is the first to report a statistically significant “sex x vitamin A” interaction, revealing a notably stronger inverse association in males than in females. This novel finding highlights the need for further research into potential sex-specific biological pathways and may inform the design of more nuanced epidemiological and public health investigations.
Source: Journal of Nutrition
Authors: Yan Sun, Hong-jiang Long, Hua Guo, Yi-ya Liu
Institution: Guizhou Center for Disease Control and Prevention
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $5,200
OpenAlex ID: W7129480879