Spirometry Changes in Normal or Early ILO Pneumoconiosis Radiographs of Sandstone-Dust Exposed Workers: A Preliminary Result
Peerawat Trakultaweesuk MD*, Naesinee Chaiear MD, MMedSc, PhD*, Watchara Boonsawat MD**, Jiraporn Khiewyoo PhD***, Phanumas Krisorn MD, MSc*, Krittin Silanun MD, MSc****
Affiliation : * Unit of Occupational Medicine, Department of Community Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand ** Unit of Respiratory Medicine and Critical care, Department of Internal Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand *** Department of Biostatistics and Demography, Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand **** Department of Community Medicine and Family Medicine, Faculty of Medicine, Thammasart University, Pathum Thani, Thailand
Objective : To estimate forced expiratory volume in first second (FEV1) decline after one-year follow-up among sandstone
workers with normal or early abnormal International Labour Organization (ILO) classification chest radiographs.
Material and Method: Fifty-two sandstone workers with an ILO classification chest radiographs profusion CAG ≤1/1,
FEV1 and forced vital capacity (FVC) that decline as measured using follow-up FVC maneuver spirometry testing were
interviewed. Work exposure, personal protective equipment, and symptoms (if any) obtained through questionnaire was also
included.
Results : The 52 participants mostly were female, average age 48±8.9 years, and mostly non-smokers. Mean of FEV1 decline
at one-year follow-up was 105.4±131.7 mL (95% CI 68.7, 142.0) with increasing of FEV1 decline among high exposure,
smokers and exposed for 10 years or more. The mean FEV1 decline among workers with all those factors was 272.0±155.5
mL. Subgroup analysis with independent t-test and multiple linear regression models revealed only FEV1 decline was found
in high exposure group. FVC decline trended similar to FEV1 decline. Mean of FVC loss was 119.4±181.1 mL (95% CI
69.0, 169.9), while mean FVC loss among those classified as high exposure smoking workers with 10 years or more of
exposure was 376.0±216.2 mL. However, the FEV1 and FVC declined among sandstone workers were at least three times
greater than Thai physiological decline.
Conclusion : Although ILO chest radiographs were normal or near normal, the FEV1 and FVC declined among silica dust
exposed workers. Therefore, FEV1 deterioration should be monitored in order to comply with the UK RCS Dust Exposed
Surveillance Guideline, especially among high exposure.
Keywords : Spirometry, FEV1, FVC, Silica dust, Occupational, Medical surveillance, ILO chest radiograph
