Objective  To analyze the relationship between breast feeding and metabolic syndrome (MS).

  Methods  Cluster sampling and cross-sectional survey were adopted to retrospectively analyze the data of 6 250 women in the database of REACTION institute. According to the breast feeding situation, all the subjects were divided into breast feeding group (n=5 786) and non breast feeding group (n=464), and the breast feeding group was further divided into ≤ 6 months group (n=243), >6 to 12 months group (n=4 612), >12 to <18 months group (n=691) and ≥ 18 months group (n=240). Correlation between breast feeding and the risk of MS was analyzed.

  Results  After adjusting potential confounding factors such as age, previous history of MS, alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamyl transpeptidase (GGT), number of pregnancies, number of abortions, number of surviving fetuses, fetal gender, gestational hypertension and gestational diabetes mellitus, women with breast feeding had a lower risk of MS than those without breast feeding (OR=0.69, 95%CI was 0.59 to 0.98). Compared to women with breast feeding less than 6 months, women with breast feeding of >6 to 12 months (OR=0.81, 95%CI was 0.76 to 1.09), >12 to <18 months (OR=0.75, 95%CI was 0.68 to 1.00) and ≥ 18 months (OR=0.78, 95%CI was 0.65 to 0.97) had a lower risk of MS.

  Conclusion  Breast feeding plays a protective role in reducing the risk of postpartum MS, and breast feeding for one year to one year and a half can reduce the risk of MS to the greatest extent.