Objective: To describe practices related to infant formula feeding: diluting and concentrating formula, mixing formula with warm tap water, sterilizing, storing prepared formula, heating in a microwave oven, putting the baby to bed with a bottle, and adding cereal and sweeteners to formula; to analyze characteristics related to compliance with recommended practices; and to examine the relation between formula handling and infant diarrhea.
Subjects/design: Subjects were mothers who fed their infants formula (more than 1,000 subjects at each infant age). Data are from the US Food and Drug Administration's Infant Feeding Practices Study (IFPS), a national longitudinal survey with a nonprobability sample. Data were collected by mail, and formula practices were included at infant ages 2, 5, and 7 months.
Statistical analyses performed: Logistic regression was conducted and percentages and odds ratios were calculated, adjusting for instruction in preparing formula from a health care professional, education, income, age, parity, work status, and breast-feeding practices.
Results: Failure to comply with recommendations was high for several practices with clear health implications; 33% of mothers mixed formula with warm tap water and up to 48% heated bottles in a microwave oven. Mothers of 2-month-old infants who received instruction from a health care professional and who breast-fed showed increased compliance, but few demographic characteristics, such as education, were related. Diarrhea increased with ambient holding of formula for older infants.
Application: Advice from a health care professional can improve formula-handling behaviors. Dietitians and other health care professionals should provide information on proper preparation and handling of infant formula to all infant caregivers.