Association between serum vitamin A and E status and recurrent respiratory tract infections in children: a propensity score-matched study

BACKGROUND: Recurrent respiratory tract infections (RRTIs) and vitamin deficiencies are significant public health concerns in pediatrics. While the immunomodulatory effects of vitamins A and E are widely recognized, their specific roles and associations with RRTIs in children require further clarification. This study aims to evaluate differences in serum levels of vitamins vitamin A and E levels between children with RRTIs and healthy controls in Xiangtan, China. It also aims to analyse the association between deficiencies in vitamins A and E during respiratory tract infections (RTIs) in children with RRTIs. METHODS: A total of 4,782 children attending the Pediatric Department of Xiangtan Central Hospital between June 2017 and December 2020 were enrolled in the study. Of these children, 3,236 had RRTIs and 1,546 were healthy controls. Serum vitamin A and E levels were measured using high-performance liquid chromatography (HPLC). To minimize selection bias, propensity score matching (PSM) was performed at a 1:1 ratio based on age, gender, and season. The levels and deficiency rates of vitamins A and E were then compared between the matched groups, and their association with RRTIs was analyzed. RESULTS: After PSM with gender, age, and season as the matching factors, the final sample size for each group was 1,213. Subsequent analysis revealed that the vitamin A levels in the RRTIs and control groups were 0.225 mg/L ± 0.087 and 0.328 mg/L ± 0.078, respectively, and the vitamin E levels were 7.93 mg/L ± 2.58 and 9.18 mg/L ± 2.55, respectively. The detection rates of serum vitamin A marginal deficiency and deficiency in the control group of healthy children were 34.30% and 4.45% respectively, and the rates of vitamin E marginal deficiency and deficiency were 14.67% and 1.15% respectively. These rates were significantly lower than those observed in the RRTIs group for both vitamin A (40.73%, 42.04%) and vitamin E (31.90%, 8.90%) (p < 0.001). CONCLUSION: Children with RRTIs exhibit significantly lower serum Vitamin A and E levels and higher deficiency rates compared to healthy group. The presence of RRTIs or RTIs is closely associated with vitamin A and E deficiencies in children, suggesting that RRTIs may exacerbate vitamin A and E depletion.