Cognitive function of children with cystic fibrosis: Deleterious effect of early malnutrition

Objective. Patients who have cystic fibrosis (CF) and experience delayed diagnosis by traditional methods have greater nutritional insult compared with peers diagnosed via neonatal screening. The objective of this study was to evaluate cognitive function in children with CF and the influence of both early diagnosis through neonatal screening and the potential effect of early malnutrition. Methods. Cognitive assessment data were obtained for 89 CF patients (aged 7.3-17years) during routine clinic visits. Patients had been enrolled in either the screened (N=42) or traditional diagnosis (control) group (N=47) of the Wisconsin CF Neonatal Screening Project. The Test of Cognitive Skills, Second Edition was administered to generate the Cognitive Skills Index (CSI) and cognitive factor scores (Verbal, Nonverbal, and Memory). Results. Cognitive scores in the overall study population were similar to normative data (CSI mean [standard deviation]: 102.5 [16.6]; 95% confidence interval: 99.1-105.9). The mean (standard deviation) CSI scores for the screened and control groups were 104.4 (14.4) and 99.8 (18.5), respectively. Significantly lower cognitive scores correlated with indicators of malnutrition and unfavorable family factors such as single parents, lower socioeconomic status, and less parental education. Our analyses revealed lower cognitive scores in patients with low plasma alpha-tocopherol (alpha-T) levels at diagnosis. In addition, patients in the control group who also had vitamin E deficiency at diagnosis (alpha-T<300 mu g/dl) showed significantly lower CSI scores in comparison with alpha-T-sufficient control subjects and both deficient and sufficient alpha-T subsets of screened patients. Conclusion. Results suggest that prevention of prolonged malnutrition by early diagnosis and nutritional therapy, particularly minimizing the duration of vitamin E deficiency, is associated with better cognitive functioning in children with CF.