[Nutritional status and influencing factors of breast milk vitamin A among lactating women in three regions of Chin].

Objective: To evaluate the nutritional status of vitamin A (VitA) in breast milk and its influencing factors among lactating women in the Weihai, Yueyang, and Baotou of China.

Methods: From May to July 2014, 403 lactating mothers at (42±7) d postpartum were recruited from three Chinese cities, Weihai in Shandong Province, Yueyang in Hunan Province, and Baotou in Inner Mongolia. Basic information of lactating women and newborns and fish intake information of the lactating women in the last month were collected. The concentration of retinol in breast milk was collected and measured using high-performance liquid chromatography to determine the levels of VitA. According to the breast milk retinol concentration, the nutritional status of breast milk VitA among the lactating women was divi-ded into deficiency (< 1.05 μmol/L) and sufficient (≥1.05 μmol/L). The multivariate quantile regression was used to calculate the adjusted breast milk retinol concentrations. The Kruskal-Wallis H test and the Mann-Whitney U test were used to test the difference of breast milk retinol concentration according to the characteristics of the lactating women. The Logistic regression was used to analyze the effect of characteristics of lactating women on breast milk VitA deficiency.

Results: The M (P₂₅, P₇₅) of breast milk retinol concentration among the Chinese lactating women was 1.15 (0.83, 1.49) μmol/L. Multivariate analysis showed that the adjusted breast milk retinol concentration was related to the regions, maternal age, ethnicity, education levels, body mass index (BMI), parity, gestational age, delivery modes, breastfeeding practice, fish intake and birth weight of the infants. The prevalence of VitA deficiency in breast milk among all the lactating women was 41.9%. In Weihai, Yueyang, and Baotou, the prevalence rates were 34.8%, 39.6%, and 51.5%, respectively. Compared with the women in Weihai, the adjusted OR for breast milk VitA deficiency among the women in Baotou was 1.75 (95%CI: 1.05-2.92). Compared with the women having college and above education, the adjusted OR for breast milk VitA deficiency among those having junior high school and below education were 2.16 (95%CI: 1.10-4.24). Compared with women with low fish intake, the adjusted OR for breast milk VitA deficiency among those with high fish intake were 0.55 (95%CI: 0.36-0.84).

Conclusion: The prevalence of breast milk VitA deficiency among the Chinese lactating women was 41.9%, suggesting that breast milk VitA deficiency in lactating women and inadequate VitA intake for infants were common in China. The women in Baotou, low educational status and low fish intake increased the risk of breast milk VitA deficiency, suggesting that attention should be paid to the nutritional status of lactating women in underdeveloped regions such as inland region, and education for health should be enhanced and food containing VitA such as fish intake should be increased.