The objective of this study is to improve the understanding of the relationship of zinc (Zn) status and growth in infant and young people with cystic fibrosis (PWCF). The investigators hypothesize that Zn deficiency in infant and young PWCF is associated with poor growth.~Aim #2: To study the association between Zn levels in red blood cells and nutritional status in PWCF at 3 months to 3 years of age and compare it to the association between serum Zn and nutritional status in the same population. Hypothesis: Lower Zn levels in red blood cells is associated with poorer nutritional status in infant and young PWCF and is a better measure of Zn status compared to serum Zn.
The purpose of this study is to improve the understanding of the relationship of zinc status and growth in infants and young children who were diagnosed with cystic fibrosis via newborn screening.