Breastfeeding status and key study variables. Breastfeeding information
was collected at each visit before the infants were 12 mo old by
asking parents a question explaining the definition of exclusive
breastfeeding. For the purpose of this study, ‘‘exclusive breastfeeding’’
was defined as feeding with only breast milk or expressed breast milk and
no other liquids or solids, with the exception of drops or syrups
consisting of vitamin, mineral supplements, or medicines according to
the WHO (27). Exclusive breastfeeding for