RELATIONSHIP BETWEEN PULMONARY TEST VARIABLES AND ASTHMA AND WHEEZING- A VALIDATION OF SELF-REPORT OF ASTHMA

We investigated the relationship between the pulmonary test variable m easurements and self-reported asthma and wheezing from a cross-section al study conducted in Saskatchewan. Based on the responses to the ques tionnaire, the subjects were classified into asthmatic, wheezing, and asymptomatic groups. For both male and female subjects the mean values of forced expiratory volume in 1 s (FEV1), forced expiratory f low du ring the middle half of the forced vital capacity (FEF25-75), and FEV1 /FVC ratio were lowest in asthmatics, followed by wheezing and asympto matic groups, respectively. This trend was also observed in forced vit al capacity (FVC) for men but not for women. After adjusting for curre nt smoking status, the trend in the means across the three groups was statistically significant in men for FEV1 (p = 0.03), FEF25-75 (P = 0. 002), and FEV1/FVC ratio (p = 0.002) and in women for FEF25-75 (p < 0. 001) and FEV1/FVC ratio (p < 0.001). The differences in the adjusted m eans of FVC, FEV1, FEF25-75, and FEV1/FVC ratio between asymptomatic s ubjects and the other two groups were significant in both male and fem ale subjects. Significant differences were also observed between asthm atics and wheezing groups in the adjusted means of FEF25-75 and FEV1/F VC ratio in male and female subjects. We conclude that the self-report of asthma has a high level of validity against the criterion of concu rrently measured pulmonary test variables.