Cross-national comparison of injury mortality: Los Angeles County, California and Mexico City, Mexico

Background Cross-national comparisons of injury mortality can suggest possi ble causal explanations for injuries across different countries and culture s. This study identifies differences in injury mortality between Los Angele s (LA) County, California and Mexico City DF, Mexico. Methods Using LA County and Mexico City death certificate data for 1994 and 1995, injury deaths were classified according to the International Classif ication of Diseases Ninth Revision-Clinical Modification external cause of injury codes. Crude, gender-, and age-adjusted annual fatality rates were c alculated and comparisons were made between the two regions. Results Overall and age-adjusted injury death rates were higher for Mexico City than for LA County. Injury death rates were found to be higher for you ng adults in LA County and for elderly residents of Mexico City. Death rate s for motor vehicle crashes, falls, and undetermined causes were higher in Mexico City, and relatively high rates of poisoning, homicide, and suicide were found for LA County. Motor vehicle crash and fall death rates in Mexic o City increased beginning at about age 55, while homicide death rates were dramatically higher among young adults in LA County. The largest proportio n of motor vehicle crash deaths was to motor vehicle occupants in LA County and to pedestrians in Mexico City. Conclusions These findings illustrate the importance of primary injury prev ention in countries having underdeveloped trauma care systems and should ai d in setting priorities for future work. The high frequency of pedestrian f atalities in Mexico City may be related to migration of rural populations, differing vehicle characteristics and traffic patterns, and lack of safety knowledge. Mexico City's higher rate of fall-related deaths may be due to c oncurrent morbidity from chronic conditions, high-risk environments, and de lay in seeking medical treatment.