Risk Factors in Stroke: A Clinical Study in Mexican Patients

Abstract

Mexicans hospitalized between July, 1967, and June, 1968, with clinically diagnosed stroke provided information on risk factors in a population from which little systematically collected information on stroke exists. The patients were beneficiaries of ISSSTE, a government-sponsored health care system. Postmortem examination in 20 patients indicated virtually 100% validity of diagnosis. Cerebral thrombosis, hemorrhage and embolus occurred in a ratio of 6:2:1. There was no sex difference in stroke frequency. Thrombosis and hemorrhage increased with age; embolus occurred more often in younger patients. Thrombosis tended to occur when at repose and in individuals with sedentary occupations; the opposite was found with hemorrhage and embolus. Obesity did not seem to predispose to stroke. Hypertension, heart disease and diabetes mellitus emerged as common antecedent conditions. There was a morning peak in onset of thrombosis and hemorrhage and an afternoon peak for embolus. No relation of onset to holidays or stress was noted. Thrombosis, hemorrhage and embolus all were associated with increased ambient temperature, and with low, slightly decreased and high humidity, respectively. An August-September (end of rainy season) peak in seasonal frequency occurred. The risk factors previously identified as being important mainly in northern populations seemed to be important in this Mexican population as well. Thus, ethnic and cultural variability exerted little effect on stroke frequency.