Dr Basco refers to the NCHS infant growth curves as "standards." Although many users view these curves as standards, and communicate as such to parents, we deliberately avoided using that term. Drs Frongillo and Garza succinctly review the significance of the use of growth references as "standards."
Dr Basco requested more information about feeding practices of the cohorts. For the Pediatric Practice Research Group (PPRG) cohort, information about infant diet was collected from parents at each visit. Fifty-six percent of the infants in the PPRG curves were at least partially breast-fed for 1 month and 40% for 6 months.1 This closely approximates the rates of breast-feeding reported in national surveys during that period.2 Most infants included in the NCHS curves were formula-fed; greater detail is unavailable.
Choosing the reference cohort for infant growth based on a concern for obesity is unfounded. It has been shown that the predictive