Self-reported physician-diagnosed chronic obstructive pulmonary disease and spirometry patterns in Vietnam Era US Army Chemical Corps veterans: A retrospective cohort study

Research on chronic obstructive pulmonary disease (COPD) and herbicide exposure in Vietnam War veterans is limited.

Survey data were collected from 3193 US Army Chemical Corps veterans on herbicide exposure and self-reported physician-diagnosed COPD. Three spirometric patterns were used to define airflow obstruction (AFO): (i) FEV₁ /FVC < 70% ("fixed ratio"); (ii) FEV₁ /FVC < lower limit of normal ("LLN"); and (iii) (FEV₁ /FVC < LLN and FVC ≥ LLN and FEV₁ 1 /FVC1  ≥ LLN) ("specific obstruction"). Associations between herbicide exposure and self-reported COPD and spirometric-AFO were determined using regression.

COPD prevalence varied (self-reports: 20.1%; spirometry: 29.8%, 12.9%, 8.4% by fixed ratio, LLN, and specific obstruction definitions, respectively). Spirometric parameters did not differ by exposure. Self-reported COPD and herbicide exposure were significantly associated (adjusted odds ratio [aOR] = 1.82, 95% confidence intervaI: 1.48,2.24). No association was found between spirometric-AFO and herbicide exposure.

A significant association was found between herbicide exposure and self-reported physician-diagnosed COPD but not when COPD diagnosis was based on spirometry.