Endotoxin and gender modify lung function recovery after occupational organic dust exposure: a 30 year study
Published Date:Feb 09 2015
Source:Occup Environ Med. 72(8):546-552.
Keywords:Air Pollutants, Occupational
Forced Expiratory Volume
Recovery Of Function
Pubmed Central ID:PMC4506722
Funding:ES00002/ES/NIEHS NIH HHS/United States
F32ES020082/ES/NIEHS NIH HHS/United States
K23 ES023700/ES/NIEHS NIH HHS/United States
NIH-NIEHSK23ES023700/ES/NIEHS NIH HHS/United States
NIOSH OH002421/OH/NIOSH CDC HHS/United States
P30 ES000002/ES/NIEHS NIH HHS/United States
The purpose of this study is to determine the trajectory of lung function change after exposure cessation to occupational organic dust exposure, and to identify factors that modify improvement.
The Shanghai Textile Worker Study is a longitudinal study of 447 cotton workers exposed to endotoxin-containing dust and 472 silk workers exposed to non-endotoxin-containing dust. Spirometry was performed at 5 year intervals. Air sampling was performed to estimate individual cumulative exposures. The effect of work cessation on FEV1 was modeled using generalized additive mixed effects models to identify the trajectory of FEV1 recovery. Linear mixed effects models incorporating interaction terms were used to identify modifiers of FEV1 recovery. Loss to follow-up was accounted for with inverse probability of censoring weights.
74.2% of the original cohort still alive participated in 2011. Generalized additive mixed models identified a non-linear improvement in FEV1 for all workers after exposure cessation, with no plateau noted 25 years after retirement. Linear mixed effects models incorporating interaction terms identified prior endotoxin exposure (p=0.01) and male gender (p=0.002) as risk factors for impaired FEV1 improvement after exposure cessation. After adjusting for gender, smoking delayed the onset of FEV1 gain but did not affect the overall magnitude of change.
Lung function improvement after cessation of exposure to organic dust is sustained. Endotoxin exposure and male gender are risk factors for less FEV1 improvement.
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