In contrast,
no significant differences were detected in the prevalence
of current wheeze or physician-diagnosed asthma. The
prevalence of severe wheezing symptoms in the past 12
months (four or more attacks of wheezing, 1 night of
sleep disturbance due to wheezing per week, wheezing that
limits speech, and exercise-induced wheezing) also
decreased significantly. Alarmingly, the prevalence and
severity of rhinitis symptoms increased significantly during
the 13-year period that was analyzed.