Examining life-course influences on chronic disease: the Ribeirão Preto and São Luís birth cohort studies (Brazil).

More than any other low- and middle-income country, Brazil has the longest research tradition of establishing, maintaining and exploiting birth cohort studies. This research pedigree is highlighted in the present issue of the Brazilian Journal of Medical and Biological Research, which contains a series of twelve papers from the Ribeirão Preto and São Luis birth cohort studies from the Southeast and Northeast of Brazil, respectively. The topics covered in this raft of reports vary and include predictors of perinatal health and maternal risk factors, early life determinants of cardiovascular risk factors in childhood and adolescence, use of health services, and a description of dietary characteristics of young adults, amongst other topics. There is also a guide to the background, objectives, sampling and protocols employed across these studies, which, together with similar pieces published in past issues of the Brazilian Journal, serve as a very useful starting point, particularly for potential collaborators. In the fervent hope that further follow-up of these cohorts will take place--we provide our own justification for cohort maintenance and extension in this issue--future data collection could include: genetic material, atherosclerosis, ascertained, for instance, by intima-media thickness, and IQ testing in children--scores from which are emerging as potentially important predictors of adult health outcomes up to six decades later.