[Study on vitamin A nutritional status of 6- to 17-year-old urban children and adolescents between 2010 and 2012 in China].

Objective: To investigate the vitamin A nutritional status of 6- to 17-year-old urban children and adolescents by analyzing serum retinol level, between 2010 and 2012 in China. Methods: Data were obtained from the China Nutrition and Health Survey in 2010-2012. Using multi-stage stratified sampling and the population proportional stratified random sampling method, 6 617 children aged 6-17 years from 32 metropolis and 41 middle-sized and small cities of China were selected. The questionnaire survey was used to collect demographic information. Blood samples were analyzed using high-performance liquid chromatography to determine serum retinol concentration, and the World Health Organization guidelines were used to evaluate the nutritional status of vitamin A. Vitamin A levels, vitamin A deficiency, and marginal vitamin A deficiency in children with different characteristics were compared. Results: A total of 3 785 cases with valid samples were obtained. The overall mean serum retinol concentration level was (1.49±0.71) μmol/L; the mean serum retinol concentration was (1.55±0.69) μmol/L for metropolis and (1.49±0.75) μmol/L for middle-sized and small cities (P>0.05). The mean serum retinol concentration was (1.52±0.78) μmol/L for boys and (1.47±0.68) μmol/L for girls (P>0.05). The mean serum retinol concentration level was (1.46±0.70) μmol/L for 6- to 11-year-old children and (1.54±0.65) μmol/L for 12- to 17-year-old children (P<0.05). The total vitamin A deficiency rate and marginal vitamin A deficiency rate was 7.69% (291/3 785) and 18.57% (703/3 785), respectively. The vitamin A deficiency rate was 8.00% (36/450) for metropolis and 7.64% (65/3 335) for middle-sized and small cities; 8.12% (155/1 908) for boys and 7.25% (136/1 877) for girls; and 8.04% (171/2 115) for 6- to 11-year-old children and 7.18% (120/1 670) for 12- to 17-year-old children. No significant differences were observed for region, sex, or age (P>0.05). The marginal vitamin A deficiency rate was 19.11% (86/450) for metropolis and 18.50% (617/3 335) for middle-sized and small cities; 18.19% (347/1 908) for boys and 18.97% (356/1 877) for girls, with no significant differences observed (P>0.05). The marginal vitamin A deficiency rate was 16.54% (350/2 115) for 6- to 11-year-old children and 21.13% (353/1 670) for 12- to 17-year-old children (P<0.05). Conclusion: The vitamin A nutritional status of 6- to 17-year-old Chinese urban children and adolescents between 2010 and 2012 has improved, and the gap between cities is narrowing. However, vitamin A deficiency overall remains high, especially in younger children, and requires specific attention.