Cohort Profile: The Mexico City Prospective Study

Resumen

The Mexico City Prospective Study (Estudio Mexicano de Cohorte Para Enfermedades Crónicas en una Población Metropolitana) is a blood-based cohort study involving follow-up of 150 000 adults (50 000 men and 100 000 women) who were aged at least 35 years when recruited in 1998–2004. The study resulted from discussions in the early 1990s about how best to measure the changing health effects of tobacco in Mexico. These discussions evolved into a plan to establish a prospective cohort study that could investigate not only the health effects of tobacco but also those of blood lipids and various other risk factors. Ideally, such a study should be big enough to assess the effects of risk factors not only overall but also in specific circumstances (e.g. at particular ages and separately in each sex) and at different levels of other risk factors (to examine possible causal interactions). In Mexico, there have been substantial decreases in overall mortality from infectious diseases over the past few decades, leaving the chronic diseases of middle age as the main causes of premature death.1 However, the effects of risk factors for chronic diseases can depend on the presence or absence of other risk factors (including some that are measurable in blood), and these could differ greatly between Mexico and Western countries. To gain a clearer understanding of the major determinants of morbidity and premature mortality in Mexico, the Mexican Ministry of Health (Secretaria de Salud SSA) decided in 1994 to help fund a large prospective cohort study of adults in Mexico City. The Ministry staff designed the study and carried out its baseline survey, while Oxford's Clinical Trial Service Unit (CTSU), with major support from the UK Wellcome Trust for this collaboration, provided technical assistance with blood collection and storage.