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

BACKGROUND: Cross-national comparisons of injury mortality can suggest possible causal explanations for injuries across different countries and cultures. This study identifies differences in injury mortality between Los Angeles (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 Classification of Diseases Ninth Revision-Clinical Modification external cause of injury codes. Crude, gender-, and age-adjusted annual fatality rates were calculated 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 young adults in LA County and for elderly residents of Mexico City. Death rates 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 Mexico City increased beginning at about age 55, while homicide death rates were dramatically higher among young adults in LA County. The largest proportion 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 prevention in countries having underdeveloped trauma care systems and should aid in setting priorities for future work. The high frequency of pedestrian fatalities 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 concurrent morbidity from chronic conditions, high-risk environments, and delay in seeking medical treatment.