Fig. 1

Flow chart of the sample selection process. Notes: Fig. 1 demonstrates the sample selection process. The final sample contains two parts: children who had ceased breastfeeding, which was 2261 (280 infants were never breastfed), and children who had not, namely censored observation. Six hundred seventy-seven children were under censored observation, including 155 lost to follow-up and 522 that continued breastfeeding after the end of the observation time. Thirty children were excluded due to lack of breastfeeding information. Our final sample size was 2938