Impact of Breastfeeding on the Nutritional Status of Infants with Cystic Fibrosis (CF) in the First Year of Life‐Results of the FIRST STUDY
Authors: Lai HuiChuan , Chin Lyanne , Schoff Suzanne , Zhang Zhumin , Greer Frank R 
Published: November 2023

Optimizing nutritional status is critical in CF infants. The 2009 CF Foundation guidelines call for breast milk(BM) as the initial type of feeding, but do not address appropriateness of exclusive or prolonged breastfeeding(BF) for CF patients with meconium ileus and/or pancreatic insufficiency. There are no recommendations for fortification of BM or formula to increase caloric and nutrient density.Objectives1)Determine growth patterns and nutritional status in infants with CF in the first year of life & relate this to feeding type 2)Assess the potential longer term benefits and risks of early exclusive breastfeeding in infants with CF on nutritional status & pulmonary disease status at 2 y –6 y of age.MethodsThe FIRST Study is an ongoing US multi‐centered prospective observational study to determine optimal feedings for infants with CF. Study endpoints include growth patterns (weight (W), length(L), W/L ratio), prevalence of anemia, and fatty acid & vitamins A,E,D status. Infants were evaluated monthly after study enrollment when feeding information was collected.Results115/160 infants have been enrolled to date, 96 of whom have completed 12 mo of the study and are included in this preliminary analysis. Infants were diagnosed at 0.8 ± 0.7 mo and enrolled at 1.6 ± 0.9 mo. Infants self selected into 1 of 3 feeding groups: exclusive BF (ExBF), exclusive formula feeding (ExFF), & mixed feeding(MF). 63% initiated ExBF,decreasing to 31% at 4 wk, 18% at 4 mo, and 15% at 6 mo. 26% initiated ExFF, increasing to 45% at 4 mo and 56% at 6 mo. 11% initiated MF which increased to 37% at 4 mo & declined to 29% by 6 mo. WHO W and L z‐scores were normal at birth and fell below normal by 2 mo regardless of feeding type. W but not L z‐scores recovered by 12 mo, but growth patterns differed significantly by feeding type. Increasing duration of ExBF was associated with lower increases in both W & L z‐scores. 40% of infants were unable to achieve 25‐OH Vit D levels ≥ 75 nmol/L despite early and sustained supplementation with a median intake of 400 IU Vit D (400–2500 IU/d). Highest rate of deficiency occurred at 4 mos. Vit A and Vit E status did not differ by feeding group. Median Vit A intake was 5751 IU (750–11,502 IU/d) and median Vit E intake was 50 IU (range 5–100 IU/d). Low vit A level ( α‐tocopherol < 5 mg/L) was observed in 14% of infants. Prevalence of low vit E (retinol < 0.2 mg/L) was very low. Hemoglobin was assessed in 70% of infants between 6 &12 mo and 33% were anemic, more prevalent (50%)in the ExBF infants who were not routinely supplemented with Fe. 83% of ExBF had iron intakes less than the RDA. Abnormal essential fatty acid status (EFA) was common before age 3 mo; 36% of infants were deficient or insufficient (triene‐tetraene > 0.01). In addition, the concentrations of the principle EFA, linoleic acid was lower in BF compared to FF infants, but no difference in DHA was noted. The prevalence of Pseudomonas aeruginosa infections did not differ between BF and FF infant.ConclusionsOur data indicate that duration of exclusive breastfeeding in CF infants during the first year of life has a potential negative impact on growth patterns and on various measures of nutritional status including growth and prevalence of Fe, vit D,and EFA deficiencies.Support or Funding InformationSupported by NIH‐RO1DK072126, R56DK109692, UL1TR000427, CFF‐LAI14A0