[Association between timing of introducing complementary foods and anemia of infants aged 6-11 months in four provinces of China]

Objective: To analyze the anemia status of infants aged 6-11 months in Beijing, Shanxi, Jiangxi and Zhejiang of China, and to explore the association between timing of introducing complementary foods and hemoglobin level, anemia of infants aged 6-11 months.

Methods: Data was from National Nutrition and Health Systematic Survey for 0-18 Years Old Children in China. A total of 1404 infants aged 6-11 months from Beijing, Shanxi, Jiangxi and Zhejiang were enrolled in this study. Demographic characteristics, socioeconomic status, birth status and complementary feeding information were collected through questionnaire survey. HemoCue Hb201+ hemoglobin analyzer was used to measure hemoglobin value. The exposure variables in this study were timing of introducing complementary foods(≤5 months, 6 months and ≥7 months), and the outcome variables were hemoglobin level and anemia rate. The association between timing of introducing complementary foods and hemoglobin level was analyzed by using multivariate linear regression model, and the association between timing of introducing complementary foods and anemia rate was analyzed by using multivariate Logistic regression model.

Results: The hemoglobin levels of infants aged 6-11 months were(114.8±11.0)g/L, (115.5±10.5)g/L in urban areas and(114.1±11.5) g/L in rural areas. The anemia rate was 28.2%, 24.0% in urban areas and 32.9% in rural areas. The hemoglobin levels of infants introducing complementary foods at ≤5 months, 6 months and ≥7 months were(114.0±11.1), (115.2±10.9) and(114.5±10.7) g/L, respectively. After adjusting for potential confounding factors, there was no significant difference in hemoglobin level between the ≤5 months group and 6 months group(F=2.37, P=0.124), and no significant difference between the ≥ 7 months group and the 6 months group(F=0.09, P=0.770). The anemia rate of infants introducing complementary foods at ≤5 months, 6 months and ≥7 months were 32.3%, 27.9% and 22.7%, respectively. After adjusting for potential confounding factors, there was no significant difference in anemia rate between the ≤5 months group and 6 months group(OR=1.26(95%CI 0.86-1.83)), and no significant difference between the ≥7 months group and the 6 months group(OR=0.65(95%CI 0.35-1.20)).

Conclusion: Anemia remains a serious problem for infants aged 6-11 months in Beijing, Shanxi, Jiangxi and Zhejiang. Timing of introducing complementary foods may not be related with hemoglobin level and anemia rate of infants aged 6-11 months.