RESPIRATORY SYMPTOMS IN CHILDREN OF UPPER SILESIA, POLAND - CROSS-SECTIONAL STUDY IN 2 TOWNS OF DIFFERENT AIR-POLLUTION LEVELS

In children aged 7-9 years residing in the town of Chorzow (C) and in the town of Mikolow (M), located 30 km apart (Upper Silesia, the indus trial part of Poland), respiratory symptoms were ascertained according to the parental answers to WHO-Questionnaire. Mean annual concentrati ons of air pollutants are higher in Chorzow than in Mikolow, and recen t mean values of 24 hr measurements over November 1992-January 1993 co nfirmed the between-town gradient (p < 0.001) for particulates (C:166 mu g/m(3); M:129 mu g/m(3)), SO2 (C:153 mu g/m(3); M:92 mu g/m(3)) and NO2 (C:69 mu g/m(3); M:26 mu g/m(3)). In Chorzow 24.8% (n = 1,142) an d in Mikolow 25.6% (n = 480) of all eligible children aged 7-9 years w ere examined. Both groups (C and M) were similar in terms of sex, fami ly history of asthma and cough lasting for 3 months (C:31.6%; M:32.3%) . Frequency of the following respiratory symptoms statistically signif icantly (p < 0.05) differed between two groups: chest wheezing (C:21.4 %; M:17.1%) and attacks of asthmatic dyspnea (C:10.3%; M:6.2%). Also, the diagnosis of asthma by physician was more prevalent in Chorzow (C: 3.5%; M:1.3%; p < 0.05). Logistic regression analysis showed that afte r controlling for family history of asthma, environmental tobacco smok e and housing condition, the place of residence (C versus M) was stati stically significantly associated with attacks of asthmatic dyspnea (p < 0.05) and a 'borderline' significance of this factor was found in r elation to wheezing (p = 0.06) and physician-diagnosed asthma (p = 0.0 7). The survey provided the estimate of the prevalence of chronic resp iratory symptoms in children living in the most polluted urban area of Poland. Although the design of the study precludes more specific etio logic conclusions on environmental exposures the apparently higher pre valence of symptoms in children living in a more polluted town deserve s further investigation.