The primary objective of this NIH funded clinical trial is to conduct a multi-center, randomized, controlled trial comparing two interventions: a behavioral plus nutrition intervention to a nutrition intervention. This study will (a) determine the impact of the behavioral intervention on energy intake and weight gain; (b) examine the durability of the behavioral intervention's impact on growth (weight and height) one year following treatment; and (c) explore the relation between physical activity and growth.

Evidence-based nutritional interventions that achieve and sustain optimal growth in young children with cystic fibrosis (CF) do not exist, despite an urgent need. Such an intervention could positively change the course of clinical lung disease and enhance survival for these children. The primary objective of this NIH funded clinical trial is to conduct a multi-center, randomized, controlled trial comparing two interventions: a behavioral plus nutrition intervention to a nutrition (attention control) intervention. All subjects will receive nutritional care consistent with the 2001 CF Consensus Conference guidelines for pediatric nutrition.

The specific aims are to:

1. determine the impact of the behavioral intervention on energy intake and weight gain;
2. examine the durability of the behavioral intervention's impact on growth (weight and height) one year following treatment; and
3. explore the relation between physical activity and growth. The central hypothesis is that behavioral intervention will lead to better growth as measured by change in weight and height for age z scores.

From three CF Centers in Ohio, (Cincinnati Children's, Columbus Children's, Rainbow Babies and Children's Hospital in Cleveland), two referral centers in Ohio (Dayton Children's and Akron Children's), one CF Center in Michigan (University of Michigan-Ann Arbor), and one CF Center in Arizona (University of Arizona-Tucson), 100 preschoolers with CF and pancreatic insufficiency age 2 to 6 years will be randomized to one of the two conditions. The two groups will be stratified so that they are similar at the initiation of treatment on weight for age z score.

Other critical variables such as history of Pseudomonas aeruginosa infection and gender will be used as covariates in the statistical analysis plan. Outcome data (energy intake measured by 7-day diet record, weight, height) will be obtained at baseline, post-treatment (6 months), and after a 12-month follow-up (18 months post baseline).

Secondary measures will include body mass index, body composition measured by dual energy x-ray absorptiometry (DXA) and skinfolds, and growth velocity. Behavioral treatment will maximize adherence to a high energy diet and enzyme replacement therapy, and motivate children to increase their energy intake. It involves 7 weekly sessions followed by 4 monthly sessions. The attention condition controls for time of contact and number of assessments conducted.

This study advances the investigation of early nutritional interventions for young children with CF and directly addresses the need for controlled, longitudinal assessment of behavioral intervention on growth. The long-range goal is to change the standard of nutritional care for young children with CF because behavioral intervention leads to optimal growth and ultimately improves lung health and survival.

Inclusion Criteria:

• confirmed diagnosis of cystic fibrosis based upon 2 of the following: a. sweat chloride by quantitative pilocarpine electrophoresis ≥60 milliequivalent/Liter (mEq/L), b. two clinical features consistent with CF, or c. genetic testing demonstrating two mutations associated with CF
• confirmation of pancreatic insufficiency based upon fecal elastase of ≤ 100 micrograms per gram of stool (or an undetectable level)
• age at enrollment to the trial of 2.0 years to 6.0 years
• at least 6 months post CF diagnosis
• consuming an unrestricted fat diet

Exclusion Criteria:

• diagnosis of developmental delay (i.e., autism, cerebral palsy, or mental retardation)
• receiving supplemental enteral nutrition via nasogastric tube, gastrostomy, or total parenteral nutrition
• diagnosed with another disease/condition (e.g., insulin dependent diabetes, congenital heart disease, significant renal disease, history of bowel resection or short bowel syndrome, colonic strictures) known to affect growth
• taking a medication (e.g., insulin, growth hormone, chronic use of systemic steroids) known to affect growth
• screening assessment shows genetic potential for height as acceptable according to the 2001 Consensus Conference guidelines and diet diary indicates daily Dietary Reference Intake (DRI) of energy average of 140% or greater (DRI of 100% will be determined as the estimated energy requirement [EER] based upon the child's age, gender, and an active physical activity level
• weight z score (age and gender adjusted) of > 1.0
• prior participation in the pilot intervention studies conducted by the PI during the prior period of R01 funding or current participation in an intervention trial conducted by the Cystic Fibrosis Therapeutics Development Network.

Adverse events were assessed at each study visit up to the final 12 month follow up assessment (18 total months from baseline).