Myocardial infarction in a low income area of Mexico City. Prevalence and clinical characteristics.

We present the results of a population based survey (The Mexico City Diabetes Study) in which the prevalence of myocardial infarction (MI) was estimated in 2282 subjects using Minnesota coded electrocardiograms (ECG). Participating individuals were men (941) and non-pregnant women (1341) between 35-64 years of age, residing in a low income area of Mexico City. Electrocardiograms were classified in three categories: definitive MI (pathological Q and QS patterns, all 1.1 codes) and prominent Q and QS patterns accompanied by negative T waves (all 1.2 codes accompanied by code 5.1 or 5.2 with the exception of 1.2.6. and 1.2.8.). Possible MI included minor Q and QS patterns (all 1.3 codes and codes 1.2.6. and 1.2.8.) and unlikely MI included all other codes. Two tracings were uncodeable (final n = 2280), ten ECGs were classified as "definitive", 39 met criteria for "possible". Due to the small number, both categories, definitive and possible were combined. The overall prevalence of MI was higher in men (3.2%) than women (1.4%). In men ECG evidence of a MI was associated with older age, higher systolic blood pressure, higher 2-h post-glucose challenge and higher fasting and post-glucose challenge insulinemia. No corresponding associations were observed in women although the number of events in women was small. The prevalence of MI in Mexico City appears to be lower than that observed in some Mexican-American populations in the southern U.S. where prevalence for men was estimated around 4% and for women 2.5% for the same age group.(ABSTRACT TRUNCATED AT 250 WORDS)