CHRONIC RESPIRATORY SYMPTOMS, SKIN-TEST RESULTS, AND LUNG-FUNCTION ASPREDICTORS OF PEAK FLOW VARIABILITY

We examined how chronic respiratory symptoms, reported in a questionna ire, and results of skin prick tests and spirometry predicted variabil ity in peak expiratory flow (PEF) among 6-12-yr-old children (n = 1,85 4). After characterization with skin tests and spirometry, children we re followed for 2-3 mo during the winter of 1993-1994. Peak expiratory flow was measured daily in the morning and evenings. Children with as thmatic symptoms (wheeze and/or attacks of shortness of breath with wh eeze in the past 12 mo and/or ever doctor diagnosed asthma) had a grea ter variation in PEF than children with dry nocturnal cough as their o nly chronic respiratory symptom. Similarly, doctor-diagnosed asthma wa s associated with a greater variation in PEF, also among children with asthmatic symptoms. Peak flow variability increased with an increasin g number of symptoms reported in the questionnaire. Atopy, positive sk in test reactions to house dust mite and cat and lowered level (as % o f predicted) in FEV1 and in MMEF were also associated with an increase d variation in PEF. All the differences were observed in both diurnal and day-to-day variation in PEF. In conclusion, chronic respiratory sy mptoms reported in a questionnaire, spirometric lung function and skin prick test results among asthmatic children predicted variation in PE F measured during a 2-3 mo follow-up. The difference in morning PEF co efficient of variation (CV) between children with asthmatic symptoms a nd 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 th an in older children.