[Association between timing for introducing complementary foods and body composition of children aged 3-5 years in five provinces of China].

OBJECTIVE

To explore the association between different timing of introducing complementary foods during infancy and the body composition of children aged 3-5 years.

METHODS

The data was from National Nutrition and Health Systematic Survey for 0-18 Years Old Children in China. A face-to-face interview to caregivers of children was conducted to retrospectively collect timing of introducing complementary foods of children aged 3-5 years. The bioelectrical impedance analysis was used to measure the body composition of children by professionally trained investigators. The exposure variable of the study was the timing of introducing complementary foods(≤5 months old, 6 months old and ≥7 months old). The outcome variables were the fat-free mass, fat-free mass index, body fat mass, body fat mass index, and percentage of body fat. According to age stratification, a multivariate linear regression model was used to calculate the mean, mean difference and 95% CI after adjusting for potential confounders.

RESULTS

After adjusting for potential confounders, there were no statistically significant difference in body fat mass, body fat mass index, percentage of body fat and fat-free mass index among different groups of timing for introducing complementary foods for children aged 3-5 years old. For children aged 3-5 years, after adjusting for potential confounders, the difference of fat free mass was statistically significant among children with different timing for introducing of complementary foods(3 years old: 12.89 kg vs. 12.66 kg vs. 12.94 kg, F=4.42, P=0.013; 5 years old: 16.27 kg vs. 16.23 kg vs. 16.66 kg, F=5.40, P=0.005). The fat free mass of children aged 3 years was lower when introducing complementary foods during 6 months of age than at ≤5 months of age(mean difference=-0.23 kg(95% CI-0.45--0.02 kg)). The fat free mass of children aged 5 years was higher when introducing complementary foods at ≥7 months of age than at≤5 months of age(mean difference=0.39 kg(95% CI 0.08-0.70 kg)).

CONCLUSION

It is found that the association between timing for introducing complementary foods during infancy and the fat mass indicators of children aged 3 to 5 years was not statistically significant, and the association between timing for introducing complementary foods and fat-free mass may be inconsistent for different fat-free mass indicators.