OSTEOPOROSIS IN AFRICAN HEMOSIDEROSIS - ROLE OF ALCOHOL AND IRON

This paper aims to examine the relative contributions made by alcohol and iron overload and hypovitaminosis C to the osteoporosis associated with African hemosiderosis. To characterize this bone disorder, we ex amined double-tetracycline-labeled iliac crest bone biopsies and serum biochemistry in 53 black male drinkers, 38 with (Fe+) and 15 without (Fe-) iron overload, and in controls. We reasoned that abnormalities f ound in both patient groups were likely to be caused by alcohol abuse and those found only in the Fe+ group to be caused by iron overload an d hypovitaminosis C (iron/C-). The patient groups differed only with r espect to greater erosion depth (p < 0.05) and abnormal markers of iro n overload in the Fe+ group. Ascorbic acid levels were lower in the Fe t group than in controls (p < 0.001). Bone volume and trabecular thick ness were significantly lower in both patient groups compared with con trols and therefore likely caused by alcohol. There were no positive c orrelations between formation and erosion variables in either patient group, which suggests uncoupling of formation from erosion, possibly a s a result of alcohol abuse, Prolonged mineralization lag time associa ted with thin osteoid seams was found in 32% of patients, affecting bo th groups. This rules out osteomalacia and suggests osteoblast dysfunc tion, probably caused by alcohol. The number of iron granules in the m arrow correlated with erosion depth (r = 0.373, p < 0.01), trabecular number (r = -0.295, p < 0.05), and trabecular separation (r = 0.347, p < 0.05). Abnormalities in these variables were therefore attributed m ainly to iron/C-. Several formation variables were significantly direc tly correlated with indicators of iron overload, suggesting that iron/ C- does not adversely affect bone formation. We conclude that alcohol abuse was predominantly associated with thinning of trabeculae and iro n overload and hypovitaminosis C with increased erosion depth and disc onnection of the trabecular network. Osteomalacia was not seen.