The primary objective of the study was to compare the growth parameters of children approximately 2* years of age, who as infants were randomized to receive either a lower-protein formula ("experimental formula"; EF) with 12.8 g/L protein or a standard formula (SF) with 14.1 g/L protein or who were human milk (HM) fed for the first 4 months of life. The secondary objective was to describe diet and nutrient intake in this cohort of children. The exploratory objectives were to describe stool microbiota in a subset of this cohort and stool composition (stool soap and nonsoap fatty acids, total fatty acids, and minerals) in a second subset of this cohort.

(* The mean age of subjects was 33.0 months due to a delay in the study start-up.)

This was an observational, single-site, follow-up study of healthy children who as infants who had completed study 9052A1-3000. An attempt was made to contact all subjects who had completed study 9052A1-3000 by telephone to ask them to participate in study 9052A1-3001. Approximately 66 and 60 subjects were planned to participate in the stool microbiota and stool composition substudies, respectively.

Inclusion Criteria:

• Children who were enrolled in the Wyeth Nutrition study are eligible to participate in this study

Exclusion Criteria:

• Children who were not enrolled in the Wyeth Nutrition study are not eligible to participate in this study
• Children who have received any antibiotics and antifungal medications except topical within two weeks prior to enrollment are not eligible to participate in the stool microbiota study
• Children who are taking any medications known or suspected to affect fat digestion, absorption, and or metabolism, any vitamin and or mineral supplements which contain calcium, suppositories, bismuth-containing medications, herbal supplements, or medications that may neutralize or suppress gastric acid secretion, are not eligible to participate in the stool composition study

Children 2 years of age who were enrolled in the Wyeth Nutrition study