Risk factors for and protective factors against breastfeeding interruption before 2 years: a birth cohort study

Background Little is known about the factors associated with the World Health Organization (WHO) recommendation of breastfeeding for at least 2 years. The objective of this study was to identify risk factors for and protective factors against breastfeeding interruption before 2 years of age. Methods In this live birth cohort, mother and infant dyads were followed for 2 years. Data collection was performed at the maternity ward and subsequently at the children's homes, monthly during the first 6 months of life and then at 9, 12, 18, and 24 months. The outcome of interest was breastfeeding interruption before 2 years of age. Median duration of breastfeeding was estimated using Kaplan-Meier's survival analysis, and the associations were tested using Cox's hierarchical multivariate model. Significance was set at 5%. Results Data from a total of 1344 dyads were assessed. Median breastfeeding duration was 385 days. The following risk factors for breastfeeding interruption were identified: white skin color (adjusted hazard ratio [HRa]: 1.31; 95% confidence interval [95%CI]: 1.10-1.56), primiparity (HRa: 1.21; 95%CI: 1.05-1.40), working outside the home (HRa: 1.52; 95%CI: 1.30-1.77), child sex male (HRa: 1.18; 95%CI: 1.03-1.35) and use of a pacifier (HRa: 3.46; 95%CI: 2.98-4.01). Conversely, the following protective factors were identified: lower family income (HRa: 0.81; 95%CI: 0.71-0.94), mother-infant bed-sharing (HRa:0.61, 95%CI: 0.52-0.73), on-demand breastfeeding in the first month (HRa: 0.64; 95%CI: 0.47-0.89) and exclusive breastfeeding at 4 months (HRa: 0.58, 95%CI: 0.48-0.70). Conclusions The findings allowed to identify both risk factors for and protective factors against breastfeeding interruption before 2 years of age. Knowledge of these factors may help prevent this event and aid in the development of programs that help women maintain breastfeeding for at least 2 years, as recommended by the WHO.