El-Zein M, Malo J L, Infante-Rivard C, Gautrin D
Joint Depts of Epidemiology and Biostatistics and Occupational Health, McGill University, Montreal, Canada.
Eur Respir J. 2003 Sep;22(3):513-8. doi: 10.1183/09031936.03.00000903.
The majority of cross-sectional studies have shown a higher prevalence of ventilatory impairment in welders while only few longitudinal studies were able to detect chronic effects on spirometry or bronchial responsiveness. The aim of the study was to determine the incidence of probable occupational asthma (OA), bronchial obstruction and hyperresponsiveness among 286 students entering an apprenticeship programme in the welding profession. This epidemiological prospective cohort study consisted of a baseline assessment survey and two follow-up assessments. A respiratory symptom questionnaire was administered at each visit. Spirometry and methacholine bronchial challenge test results, conducted once prior to onset of exposure and later after an average of 15 months of apprenticeship, were available for 194 subjects. The incidence of probable OA was approximately 3% (6 of 194). The incidence of bronchial hyperresponsiveness, defined as a > or = 3.2-fold decrease in the provocative concentration causing a 20% fall in the forced expiratory volume in one second from baseline to the end of the study was 11.9%. A statistically significant difference was found between the baseline and end of study for the lung function values. In particular, the forced expiratory volume per cent predicted had significantly dropped by 8.4% on average. The significance of these early pulmonary function changes in relation to possible chronic effects of exposure to welding fumes and gases remains to be explored.
大多数横断面研究表明，焊工中通气功能障碍的患病率较高，而只有少数纵向研究能够检测到对肺活量测定或支气管反应性的慢性影响。本研究的目的是确定286名参加焊接行业学徒计划的学生中可能的职业性哮喘（OA）、支气管阻塞和高反应性的发病率。这项流行病学前瞻性队列研究包括一次基线评估调查和两次随访评估。每次随访时都进行了呼吸症状问卷调查。194名受试者提供了暴露开始前和平均学徒15个月后的肺活量测定和乙酰甲胆碱支气管激发试验结果。可能的OA发病率约为3%（194人中6人）。支气管高反应性的发病率为11.9%，定义为从基线到研究结束时，引起一秒用力呼气量下降20%的激发浓度下降≥3.2倍。研究发现，肺功能值在基线和研究结束时存在统计学显著差异。特别是，预计的用力呼气量百分比平均显著下降了8.4%。这些早期肺功能变化与接触焊接烟尘和气体可能产生的慢性影响之间的关系仍有待探索。
