Associations between each measurement of breastfeeding history and metabolic syndrome in all participants and by age group, when incorporating only covariates that preceded breastfeeding history in time.

Abbreviations: OR, odds ratio; CI, confidence interval. a, b, c Each index of breastfeeding history was measured and categorized in the same way as those in Tables 1 and 2. d Adjusted for age, residential area, educational attainment, age at first delivery, and parity. The categories of these covariates were the same as those in Table 2. (XLSX)