Vírus causadores de infecção respiratória: na simplicidade mora a inteligência

Abstract

LETTERS TO THE EDITORNo conflicts of interest declared concerning the publication of this letter. Jayme MurahovschiLivre Statistical and epidemiological methods in prevalence studies: odds ratio vs. prevalence ratio ♦ Dear Editor, When reading the article by Rodrigues et al., 1 "The association between cardiorespiratory fitness and cardiovascular risk in adolescents," it was possible to find some errors regarding the application of statistical and epidemiological methods, as well as their respective interpretations; however, in our opinion, this does not invalidate the findings, but it can depreciate the scientific method of that study, which is not desirable for the authors, readers or even Jornal de Pediatria, which is such an important journal.That article is a result of a cross-sectional study, i.e., a prevalence study, situation in which association estimates are preferentially calculated by prevalence ratio (PR) or, less adequately, by odds ratio (OR) and their respective 95% confidence intervals (95%CI). That is so because, in this type of study, it is not possible to determine incidence. Analyzing the results, one can see that OR and relative risk (RR) were used as association estimators. Both are inadequate, since it is known that OR overestimates strength of association, 2,3 and 96