Cross-shift and longitudinal changes in FEV₁ among wood dust exposed workers

Objectives: Acute lung function (LF) changes might predict an accelerated decline in LF. In this study, we investigated the association between cross-shift and longitudinal changes in forced expiratory volume in 1 s (FEV₁) among woodworkers in a 6-year follow-up study. Methods: 817 woodworkers and 136 controls participated with cross-shift changes of FEV ₁ at baseline and FEV₁ and forced vital capacity at follow-up. Height and weight were measured and questionnaire information on respiratory symptoms, employment and smoking habits was collected. Wood dust exposure was assessed from 3572 personal dust measurements at baseline and follow-up. Cumulative wood dust exposure was assessed by a study-specific job exposure matrix and exposure time. Results: The median (range) of inhalable dust at baseline and cumulative wood dust exposure was 1.0 (0.2-9.8) mg/m ³ and 3.8 (0-7.1) mg year/m³, respectively. Mean (SD) for %ΔFEV₁/workday and ΔFEV₁/year was 0.2 (6.0)%, and -29.1 (41.8) ml. Linear regression models adjusting for smoking, age, height and weight change showed no association between cross-shift and annual change in FEV₁ among woodworkers or controls. Including different exposure estimates, atopy or cross-shift change dichotomised or as quartiles did not change the results. Conclusions: This study among workers exposed to low levels of wood dust does not support an association between acute LF changes and accelerated LF decline.