Nitrogen balance in adolescent sickle cell patients

There is little explanation for the somatic growth retardation seen in sickle cell patients (sicklers). The study attempts to explain this problem by comparing nitrogen balance in adolescent sicklers (n = 9) and normals (n = 6). Nitrogen balance was determined at 3 dietary nitrogen intake levels of 90, 135 and 180 mg/kg/day. Energy intake was kept constant. Twenty-four-hour stool and urine were quantitatively collected for 5 days and analysed for total nitrogen. Faecal and urinary nitrogen excretions were significantly greater in sicklers than in the normals (P < 0.05). At the lowest nitrogen intake level (90 mg/kg/day), the normals were in positive nitrogen balance whereas the sicklers were in negative balance even at the highest nitrogen intake level (180 mg/kg/day). It is predicted that sicklers need about 190 N/kg/day to be in positive nitrogen balance. Poor nitrogen economy therefore contributes to the poor growth of the sickler.