Prevalence of respiratory symptoms in school children and salivary IgA--an epidemiological study in a rural area of Northrhine-Westphalia, Germany.

An elevated frequency of wheezing was found in school children in a rural area of Northrhine-Westphalia, Germany (Duhme and Keil, Institut für Epidemiologie und Sozialmedizin, Universität Münster, Münster, Germany 1997). In this study the prevalence of wheezing was reinvestigated by including main influencing factors. A cross-sectional survey was performed in all school children visiting school classes 1, 2 and 7, 8 (n = 1161).