Readability of infant formula preparation instructions is universally poor, which may result in inaccurate infant feeding. Given that inaccurate formula dispensing can lead to altered infant growth and increased adiposity, there is an increased need for easy to follow instructions for formula preparation. We hypothesize that altering infant formula instruction labels using feedback from iterative focus groups will improve the preparation accuracy of powdered infant formula in a randomized controlled trial. Participants were recruited from the community, 18 years of age or older, willing to disclose demographic information for focus group matching, and willing to participate freely in the first (n = 21) or second (n = 150) phase of the study. In the second phase, participants were randomized to use the standard manufacturer instructions or to use the modified instructions created in the first phase. Accuracy was defined as the percent error between manufacturer-intended powder formula quantity and the amount dispensed by the participant. Participants who were assigned to the modified instructions were able to dispense the powdered formula more accurately than participants who used the standard manufacturer instructions (-0.67 ± 0.76 vs. -4.66 ± 0.74% error; p < 0.0001). Accuracy in powdered formula dispensing was influenced by bottle size (p = 0.02) but not by body mass index (p = 0.17), education level (p = 0.75), income (p = 0.7), age (p = 0.89) or caregiver status (p = 0.18). Percent error of water measurement was not different between the groups (standard: -1.4 ± 0.6 vs. modified: 0.7 ± 0.6%; p = 0.38). Thus, caloric density was more accurate in the modified instructions group compared to the standard manufacturer instructions group (-0.3 ± 0.6 vs.-2.9 ± 0.9%; p = 0.03). Infant formula label modifications using focus group feedback increased infant formula preparation accuracy.
Keywords: feeding; infant formula; infant growth.