Background: Zinc plays a critical role in innate immunity. It is associated physiologically with defensin release, autophagy, and TNF alpha regulation, while supplementation of zinc in animal models decreases intestinal permeability, and bacterial biofilm formation. The goal of the present study was to evaluate the possible role of zinc levels as a biomarker for adverse outcomes such as early complications or surgery.
Methods: The GROWTH CD study (Growth, Relapses and Outcomes With Therapy) followed newly diagnosed children with CD for 24 months and was geared to predict early outcomes such as complications and surgery. Children underwent colonoscopy, gastroscopy and imaging, were phenotyped by the Paris classification and followed at baseline, 8, 12, 26, 52, 78, 104 weeks. Serum for zinc levels was obtained at baseline, and analyzed in a central laboratory. We evaluated sustained remission and complications through follow up using dichotomous and quartile analysis.
Results: 125 children were followed prospectively for 2 years, of whom 34 (27.4%) developed complications and 8 (6.6%) required surgery. At baseline median zinc levels were 86.6 mcg/dl and low levels (below 70 mcg/dl) were found in 33 (26.4%) children.
There was no correlation between serum zinc and CRP (p=0.24) or PCDAI (p=0.69).
For those with low Zinc levels at baseline compared to those with normal zinc levels, no difference was observed in rates of sustained remission by 78 weeks (59% vs. 58%, p-value=0.9); or in rates of complications or surgery by week 104 (33.3% vs. 25.3% for complications p-value=0.37, 9.7% vs. 5.6% for surgery, p-value=0.43). The rate of complications by week 104 at the lowest quartile of baseline zinc levels was 32% and at the highest quartile 23% (p=0.5).
Conclusions: Zinc levels were not useful as a biomarker of adverse outcomes in children with newly diagnosed Crohn's disease.
Supported by grants from ECCO and the Thrasher Research Fund