2. Materials and Methods
Obesity, kidney anomalies
OBESITY, RECRUITMENT, KIDNEY, POLAND
The EU-Childhood Obesity Project (NCT00338689) is a multicenter, double-blind, randomized dietary intervention trial. Recruitment was conducted in five European countries (Germany, Poland, Italy, Belgium, and Spain) between October 2002 and July 2004. Healthy singleton term infants with birth weight > 2500 g were enrolled during the first 2 months of life. Formula-fed infants were randomly assigned to either a lower-protein-content formula (1.25 g/dL and 2.05 g/dL of protein in infant formula and follow-on formula, respectively) or a higher-protein-content formula (1.6 g/dL in infant formula and 3.2 g/dL in follow-on formula). A group of breastfed infants was recruited as a control group. Further details on the clinical trial were published elsewhere [Kidney ultrasound was performed at 6 months in all centers but Italy. Infants with kidney anomalies were excluded from analysis. The results of the 6-month assessment and the possible mechanisms implicated have already been published by Escribano et al. [At 11 years of age, a new follow-up on kidney growth was performed in Poland and Spain. 