In the NHANES III analysis, a positive association of current smoking was found with the presence of wheezing, but not with current asthma, suggesting possible confounding or misclassification with non-asthma causes of wheezing, such as emphysema or chronic bronchitis [ 24].
An asthma cohort study in Southern California observed that, in that cohort, girls were less likely to play team sports and spent less time outdoors than boys [ 68], possibly contributing to differences in ozone exposure misclassification and observed associations with asthma outcomes.
In addition, although a validated algorithm was used for identifying children with asthma, the misclassification of asthma status could still occur, for example, since anti-asthma medications are used by children with wheezing without asthma.
Misclassification of asthma in children with Down syndrome.
First, the use of registry-based ICD-10 codes to identify children with asthma is likely to result in some misclassification.
Additionally, avoidance behavior (prior exposure reductions by persons with asthma) may be a source of past exposure misclassification with assessment of only current or recent exposure.
9 We assumed that the rate of misclassification of asthma status was the same for patients with and without skin cancer (ie, non-differential misclassification).
Misclassification errors and extreme outliers can be a problem in the follow-up period, particularly for persons labeled with asthma who have vocal cord dysfunction or conversion disorders, or COPD patients who have hospitalizations that last for weeks.
These results may be explained by a likely selection problem combined with diagnostic misclassification of early asthma, but we have little reason to believe that the associations could have been reversed.
He struggled with asthma.
