DIABETIC RETINOPATHY IN NIGERIANS - A STUDY OF 758 PATIENTS

Diabetic retinopathy is an uncommon complication of diabetes mellitus in Nigerian patients. The incidence is 4-6 per cent. in 758 patients. 6o per cent. of the 35 patients seen belong to the higher social classes. All the patients but two had maturity-onset diabetes mellitus. Two young patients had pancreatic calcification and biochemical evidence of exocrine disease of the pancreas. There is a positive correlation of diabetic retinopathy with duration of diabetes; and with the presence of albuminuria in patients with duration of diabetes mellitus exceeding IO years. In 40 per cent. of the patients with retinopathy, however, albuminuria was absent. There is no correlation between retinopathy and neuropathy. Diabetic retinopathy is less common in Nigerian patients than in South African Bantus. Although hypertension and albuminuria are common in Nigerian patients suffering from diabetes mellitus, peripheral gangrene, absence of peripheral pulses, and myocardial ischaemia are rare. Histological evidence of diabetic microangiopathy is also uncommon. Serum cholesterol level is raised in Nigerian patients with diabetic retinopathy, compared with those without retinopathy, but is of the same level as in normal Nigerians in the upper and middle social classes. The various factors which may be responsible for the rarity of diabetic retinopathy in Nigerians and in most African Negroes are commented on.