Longitudinal study of growth parameters in beta-thalassemia major on oral iron chelation

ABSTRACT

Children with thalassemia suffer from growth retardation. It had mainly been attributed to iron overload in the tissues and endocrine glands, chronic anemia, hypersplenism, folic acid deficiency, delayed or absent puberty. In addition a direct toxic effect on the bones has been observed in patients, before and during puberty, receiving continuous subcutaneous chelation therapy. The aim of this work is to monitor the growth of children with beta-thalassemia on oral iron chelation for early detection of growth and pubertal disorders. In this study, auxological, pubertal and laboratory data of 82 patients with beta-thalassemia major on hypertransfusion regimen and adjusted oral iron chelation following up at the hematology clinic at Cairo University Children's Hospital are studied. Height, weight, Body Mass Index, and US/LS ratio were followed up on a 3-monthly basis, over a period of 4 years. Height velocity and bone age were assessed yearly. Serum ferritin, thyroid including free T3, freeT4 and TSH and parathyroid functions including serum calcium, albumin, alkaline phosphatase and parathormone, folic acid, vitamin B12 levels, were measured in 38 of the cases at the end of the study and compared to 20 age and sex matched control. In this study 24/82 [29%] of the patients are short and remained so during the study. The US/LS ratio was abnormal in 17 cases [21%] and the ratio normalized in 7 by the end of the study. Bone age improved by the second year and returned slowed down thereafter. 52% of adolescents suffered pubertal delay and 35% needed HCG replacement to induce puberty. Serum ferritin, B12 and folic acid, Parathormone, calcium, phosphorus, alkaline phosphatase, free T3, T4, TSH were significantly different from controls. Patients in this series are hypocalcemic, hypoalbuminemic, with 65% B12 and 71% folic acid deficient, 8% had preclinical hypothyroidism while 34% had clinical hypothyroidism, one third are short and half of them have delayed puberty. The stature is not correlated to thyroid status. There was a significant correlation of height SDS and folic acid and albumin. Upper segment/Lower segment ratio was correlated to serum albumin, calcium and parathormone. Short stature is common among thalassemic patients. Puberty is delayed in half of them. Egyptian children with thalassemia are hypocalcemic, hypoalbuminemic, with an increased incidence of hypothyroidism, B12 and folic acid deficiency. Emphasis must be put on an adequate, balanced nutrition in these children with increased cell turn over