ASTHMA AND AIRWAY HYPERRESPONSIVENESS AMONG BELGIAN CONSCRIPTS, 1978-91

Background - Although there is convincing evidence that the prevalence of asthma among children has increased over the last three decades, i t remains uncertain whether such an upward trend has occurred in adult s. The aim of this study was to assess whether the prevalence of asthm a has changed in young Belgian adults in recent years. Methods - A ret rospective analysis was conducted of available statistics from the Bel gian Armed Forces for the period 1978-91 because conscripts who report ed a history of past or current asthma at call-up examination underwen t standardised assessment of non-specific airway responsiveness by mil itary chest physicians. Exemption from military service due to asthma was strictly based on the objective evidence of airway hyperresponsive ness. Results - A mean of 48 331 conscripts aged 17-31 years were exam ined annually from 1978 to 1991. The prevalence of reported asthma ros e from 2.4% in 1978 to 7.2% in 1991, while the proportion of asthmatic s with airway hyperresponsiveness remained little changed at 48.4% in 1978 and 51.4% in 1991. Conclusions - The observed increase in prevale nce of reported asthma was not accompanied by a decrease in the propor tion of conscripts with objectively measured airway hyperresponsivenes s. These observations provide supporting evidence that the increase in asthma symptoms was not simply due to reporting bias.