Epidemiology of traumatic brain injury in Johannesburg--II. Morbidity, mortality and etiology.

Using the method described in Part I (p. 283), data on the epidemiology of traumatic brain injury (TBI) in Johannesburg are presented. The overall annual incidence of TBI is 316 per 100,000. Data for Africans and Whites show marked contrasts. Among Africans, incidence is 355/100,000, with a male-female ratio of 4.4, and 763/100,000 for males aged 25-44; for Whites, it is 109/100,000 overall, with a male-female ratio of 40.1, and 419/100,000 for men aged 15-24. The overall incidence of fatal TBI is 80/100,000, with a case fatality ratio of 0.20. Interpersonal violence accounts for 51% of nonfatal TBI among Africans, as against 10% for Whites, while motor vehicle accidents cause 27% of African nonfatal TBI and 63% among Whites. Some explanatory hypotheses for this race- and sex-specific skewing of the incidence and causes of TBI are developed.