P Pr re ev va al le en nc ce e a an nd d c ch ha ar ra ac ct te er ri is st ti ic cs s o of f c ch hi il ld dr re en n w wi it th h c ch hr ro on ni ic c r re es sp pi ir ra at to or ry y s sy ym mp pt to om ms s i in n e ea as st te er rn n F Fi in nl la an nd d ABSTRACT: The objective of the present study was to assess the prevalence of asthma and asthma-related symptoms in Finland. We also wondered whether chronic cough may be an indicator of occult asthma. Prevalence and characteristics of children with doctor-diagnosed asthma and chronic respiratory symptoms were investigated in 7-12 year old school children from eastern Finland by using a questionnaire on respiratory symptoms. In addition, skin-prick tests, flow-volume spirometry, and serum total immunoglobulin E (IgE) measurements were performed in children reporting chronic respiratory symptoms.The parent-reported prevalence of doctor-diagnosed asthma was 4.4%, of wheezing 5.4%, of attacks of shortness of breath with wheezing 4.6%, and of dry cough at night 12%. Children with dry cough only (n=195) had less frequent parental asthma, self-reported allergies, daily respiratory medication, and moisture stains or molds at home than asthmatic children (n=180), but these findings were more frequent than among asymptomatic children (n=2,169). The prevalence of at least one positive skin-prick test result was 79% among the asthmatic children and 55% among children with dry cough only. There were no differences between the two symptom groups in serum total IgE levels and spirometric lung functions, except in maximal mid-expiratory flow (MMEF) values, which were significantly lower among children with asthmatic symptoms.The present results support the hypothesis that chronic cough may be an indicator of occult asthma. Therefore, to improve the sensitivity of respiratory questionnaires designed to detect asthma, they should also include questions on chronic cough. In contrast to what has been suggested previously, the prevalence of childhood asthma in eastern Finland was similar to the prevalences reported from other parts of Finland and from other Western European countries.

Our findings were probably due to a combination of early impact and later avoidance of these risk factors. The effects of some risk factors were found to differ significantly between regions. No overall pattern between air pollution and asthma was seen, but air pollution differed less than expected between the areas.

We examined how chronic respiratory symptoms, reported in a questionnaire, and results of skin prick tests and spirometry predicted variability in peak expiratory flow (PEF) among 6-12-yr-old children (n = 1,854). After characterization with skin tests and spirometry, children were followed for 2-3 mo during the winter of 1993-1994. Peak expiratory flow was measured daily in the morning and evenings. Children with asthmatic symptoms (wheeze and/or attacks of shortness of breath with wheeze in the past 12 mo and/or ever doctor diagnosed asthma) had a greater variation in PEF than children with dry nocturnal cough as their only chronic respiratory symptom. Similarly, doctor-diagnosed asthma was associated with a greater variation in PEF, also among children with asthmatic symptoms. Peak flow variability increased with an increasing number of symptoms reported in the questionnaire. Atopy, positive skin test reactions to house dust mite and cat and lowered level (as % of predicted) in FEV1 and in MMEF were also associated with an increased variation in PEF. All the differences were observed in both diurnal and day-to-day variation in PEF. In conclusion, chronic respiratory symptoms reported in a questionnaire, spirometric lung function and skin prick test results among asthmatic children predicted variation in PEF measured during a 2-3 mo follow-up. The difference in morning PEF coefficient of variation (CV) between children with asthmatic symptoms and children with cough only was somewhat bigger in girls than in boys. The effect of atopy on morning PEF CV was somewhat bigger in young than in older children.

School-aged children often experience acute respiratory symptoms. In a multicentre European study, the association between chronic respiratory symptoms (reported in a questionnaire), skin-prick test results, and lung function, and the occurrence of acute respiratory morbidity, was examined among children aged 6-12 yrs with chronic respiratory symptoms. Children with chronic respiratory symptoms, living in 10 European countries, were selected from a parent-completed questionnaire (n=4,307). Atopy was measured with skin-prick tests, and lung function with spirometry. A total of 1,854 (86% of those in the initial cohort) children kept a successful daily diary regarding their respiratory symptoms for 2-3 months. In multivariate logistic regression analyses, children with asthmatic symptoms, particularly those with doctor-diagnosed asthma, had a greater risk of occurrence of lower respiratory symptoms (odds ratio (OR): 6.12; 95% confidence interval (CI): 4.99-8.35) than children with a dry nocturnal cough as their only symptom. Atopy, particularly a positive reaction to indoor allergens, was significantly associated with occurrence of lower respiratory symptoms. For atopy the OR was 1.62 (95% CI: 1.34-1.96). A reduced level of maximal mid-expiratory flow was associated with an increased risk of lower respiratory symptoms, cough and phlegm. The associations were similar in Scandinavia, Central Eastern, Western and Southern Europe. To conclude, asthmatic symptoms reported in a questionnaire, atopic status and a reduced level of maximal mid-expiratory flow were associated with the occurrence of acute respiratory symptoms, especially those of lower respiratory symptoms.