Medidas epidemiológicas de frequência e efeito fuzzy

Abstract

The classic epidemiological measures of frequency and effect are obtained from frequentist information, resulting from the dichotomization of individuals when they are categorized according to the phenomena studied in the population. This way of categorizing disregards the subjectivities and uncertainties inherent to the individual's exposure/disease process, thus generating losses in information from the beginning of obtaining these measures. This study presents as an alternative to classical epidemiological measures, measures based on the Theory of Probability of Fuzzy Events, which flexibly categorizes the individual through the Theory of Fuzzy Sets, incorporating subjectivities and uncertainties, resulting in a more reliable measure to reality. The objective was to propose a set of epidemiological measures of frequency and fuzzy effect observing the gain of information against the classic measures, using in an unprecedented way, the Theory of Probability of Fuzzy Events. In addition, a fuzzy epidemiological study was proposed, and progress was made in the search for new fuzzy epidemiological measures calculated based on the Theory of Possibilities. To evaluate the theoretical proposals, we started with existing data from a real prospective cohort study of common mental disorder associated with food insecurity in mothers with children under one year old in two public maternity hospitals in the city of João Pessoa in the state of Paraíba. The individual was categorized in the events of the study according to the Theory of Fuzzy Sets and the new measures were calculated according to the proposed methodology. Some calculated values of the measures based on the Theory of Probability of Fuzzy Events corroborated with the classic measures and others differed, however, the Risk Ratio of Fuzzy Events highlights in its value that the exposure to food insecurity of these data in fact exposes mothers to risk of common mental disorder. The differentiated information from the new measures of frequency and effect proposed based on the Theory of Possibilities are able to describe the evolution of the worsening of the outcome under study according to the degree of exposure, indicating the moment of the explosion of cases in observational studies, this information is not observable in classical measurements. The results of the proposed epidemiological measures of fuzzy possibilities combined with the epidemiological measures of probability of fuzzy events are capable of helping the development of models to support decision-making by health managers for any outcome of interest.