الفهرس 
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Abstract
Thalassemia is a heterogeneous group of autosomal recessive disorders of limited or absent production of the alpha or beta globin chain of hemoglobin, the clinical classification of thalassemia is transfusion dependent (TDT) and non-transfusion dependent (NTDT) was proposed and then adopted by the Thalassemia International Federation. Among the complications in TDT, iron deposition and structural damage of the pancreas, pituitary, parathyroid, thyroid, adrenal glands and the gonads have been demonstrated.
Zinc is a trace element involved in synthesis of many other properties such as cholesterol, fat and more than 300 enzymes and immune and antioxidant system, it has essential role in red blood cell survival and its deficiency leads to membrane fragility.
In TM several factors contribute to zinc deficiency such as limited diet, increased urinary zinc excretion, iron chelation and ongoing hemolysis.
The pancreas has two main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar.
Impairment of the endocrine and exocrine function of the pancreas is a common complication in patients with thalassemia major.
The aim of this study is to assess the effect of zinc deficiency on the endocrine and exocrine function of the pancreas in patients with transfusion dependent thalassemia (TDT).
This study included 40 TDT children and 40 normal controls. All were subjected to thorough history taking, complete medical examination and laboratory investigations (oral glucose tolerance test, insulin, zinc, lipase, amylase and HOMA-IR).
Our results revealed that TDT children had significantly higher serum ferritin level and lower serum zinc level than controls.
Regarding the endocrine pancreatic function, TDT children had significantly more frequently impaired glucose tolerance test, higher fasting serum insulin level and HOMA-IR than controls.
While on assessing the exocrine pancreatic function, serum amylase was significantly lower in TDT children than controls and on the contrary, serum lipase was significantly more frequently abnormally high in those patients.
On comparing the endocrine and exocrine pancreatic functions in TDT children with thalassemia according to their zinc status, cases with low serum zinc had significantly more frequently impaired glucose tolerance test than cases with normal serum zinc. Also, they had significantly more frequently abnormally high HOMA-IR. Serum lipase was found to be significantly higher in cases with low serum zinc than those with normal serum zinc.
On comparing serum ferritin in TDT children according to their zinc status, this study reported higher serum ferritin levels in cases with low serum zinc than those with normal serum zinc.
There were significant negative correlations between serum zinc and both serum lipase and serum ferritin. Serum ferritin had significant positive correlations with GTT, fasting insulin level, HOMA-IR and serum lipase.
Serum zinc was significantly lower in cases having serum ferritin above ferritin threshold (≥2500ng/ml) than those with serum ferritin below ferritin threshold. Also, cases above ferritin threshold had significantly more frequently impaired glucose tolerance test and abnormally high serum fasting insulin level and serum lipase than cases below ferritin threshold.
Low serum zinc was the only risk factor reaching statistical significance as its odds ratio for exocrine pancreatic dysfunction represented by serum lipase enzyme was 23.37 and its odds ratio for endocrine pancreatic dysfunction represented by HOMA-IR was 3.9.
In conclusion, TDT children have significantly higher serum ferritin level and lower serum zinc level, which in turn affects both the endocrine and exocrine pancreatic functions in these patients.