Atopy, asthma symptoms, and eosinophilic airway inflammation in British woodworkers

ObjectivesAlthough wood dust remains a leading cause of occupational asthma (OA) in Great Britain, there have been no recent studies in British woodworkers. This cross-sectional study examined asthma risk factors in woodworkers across exposure groups. MethodsParticipants answered a respiratory questionnaire and underwent fractional exhaled nitric oxide (FENO), spirometry, and specific immunoglobulin E measurements. Wood dust exposure was assigned through a specific job-exposure matrix. Multiple regression evaluated asthma risk factors identified a priori including wood dust exposure, atopy, and current asthma symptoms. ResultsA total of 269 woodworkers participated. Median wood dust exposure was 2.00mg/m3 (IQR 1.14 mg/m3). Current asthma symptoms (CAS), work-related respiratory symptoms (WRRS) and eosinophilic airway inflammation (FENO >40ppb) were common, present in 46%, 11% and 19% of the cohort, respectively. Atopic woodworkers were at increased risk of WRRS (OR 2.78, 95% CI 1.11 - 6.92, p<0.05), asthma (OR 3.40, 1.49 - 7.81, p<0.01), and FENO >40ppb (unadjusted OR 2.00, 1.03 - 3.88, p<0.05). No effect was seen for airflow obstruction. Workers with CAS were at increased risk of WRRS and ever asthma (4.29, 2.12 - 8.69, p<0.001) but not FENO >40ppb or airflow obstruction. Increasing exposure did not significantly increase risk of asthma symptoms, asthma, airflow obstruction and inflammation. ConclusionsAsthma symptoms were prevalent among British woodworkers, even at low exposure levels. Atopy significantly increased asthma risk, particularly among symptomatic woodworkers. Further studies to phenotype and endotype populations of workers at risk of, and suffering from, wood dust OA will inform future approaches to screening and diagnosis in these populations. What is already known on this topicWood dust is a leading cause of occupational asthma (OA) in Great Britain. No recent studies have described risk factors for OA in British woodworkers. Evidence identifies atopy, asthma symptoms, and wood species as risk factors for OA, but not consistently so. What this study addsThis cross-sectional study used a detailed job-exposure matrix, questionnaire and clinical data to understand risk factors for asthma in British woodworkers. We found upper airway, asthma symptoms (CAS), work-related symptoms and eosinophilic airway inflammation to be common among British woodworkers, but specific sensitisation to wood dust was low. Among workers with asthma symptoms atopy significantly increased the risk of CAS, asthma, and airway inflammation in woodworkers. Increasing wood dust exposure was not associated with an increased risk of asthma symptoms or asthma. How this study might affect research, practice or policyThis research provides the first epidemiological study on asthma in British woodworkers for decades and highlights specific risk factors for asthma in this group. This data is useful to inform health surveillance programmes and may help inform any future review of exposure limits. This research also helps to understand the phenotype of asthma caused by wood dust which is an area requiring further exploration.