The occurrence, recrudescence, and worsening of asthma in a population of young adults - Impact of varying types of occupation

Objective: To describe the rates of exacerbation of existing asthma and inc idence of new disease in Israeli men during military service. Design: All 17-year-old Israeli nationals are obliged by law to appear at t he Israel Defense Forces (IDF) recruiting office for medical examination. T he medical history of army recruits was noted during the 30-month period af ter their induction into the IDF, and medical examinations were performed b y pulmonary specialists in all suspected cases of asthma, The duty status o f thee soldiers in combat units (CUs), maintenance units (MUs), and clerica l tasks was related to their asthma status, Results: Of a total of 59,058 r ecruits, 1.0% developed asthma during the 30 months of this study; of those in CUs, 1.2% developed asthma; of those in MUs, 0.8% del eloped asthma; an d of those pet-forming clerical tasks, 0.6% developed asthma, The relative risk for developing or worsening of asthma was related to both the preexist ing asthma statics of the recruit and the environment in which he carried o ut his military service. The annual incidence of occupational-related asthm a in MUs was found to be 800/million: five to six times the rates reported elsewhere. Conclusions: Service in CUs was associated with an increased frequency of e xacerbation of asthma. among recruits with previous disease and with the ap pearance of disease de novo. "Normal" conscripts with a history of childhoo d asthma are at a higher risk of developing overt asthma when compared to s ubjects with no such history. We found a 25% relative excess of incident ca ses of asthma in soldiers posted in MUs compared to those performing cleric al tasks [(0.8 to 0.6%)/0.8%]. This difference is probably attributed to di e difference in occupational hazards in these categories. Further studies a re needed to determine if this represents the elicitation of underlying pre existing airway lability by new work demands or other environmental conditi ons, or if this represents a new development of airway lability because of specific immune or nonimmune factors.