[Childhood asthma and risk factors].

Abstract

INTRODUCTION: This article summarizes the contribution of epidemiology to the understanding of childhood asthma. The first task in epidemiology is to determine prevalence and incidence of any disease. PREVALENCE: Epidemiological investigations are aimed at evaluating hypotheses about causes of disease by defining demographic characteristics of a certain population as well as by determining possible effects of environmental factors. In spite of some limitations, data obtained by epidemiological investigations have been valuable in confirming both the increasing incidence of asthma and the differences in prevalence in certain population groups. The observance of this phenomenon has led to much speculation and a lot of attempts to identify the reasons behind the rising prevalence. RISK FACTORS: Epidemiological studies have identified risk factors for the development of childhood asthma and provided insight into natural history of disease and prognosis. Factors ranging from increased numbers of immunizations to increased air pollution have been suggested, but subsequent analysis has failed to provide the supporting evidence to implicate most of these possibilities. The concept known as the hygiene hypothesis has gained some support from epidemiological studies. CONCLUSION: The development of asthma as well as its severity are affected by numerous factors and their interactions can he explained by the heterogeneous nature of this disease.