Occupational
Chronic respiratory disease risk among Veterans of the United States military in the Long-term Impact of Fuel Exposure (LIFE) Study Nicholas A. Tilton* Nicholas Tilton Elizabeth R. Heitz Justin G. Bergeron Jennifer A. Rusiecki Gregory Wolff Aaron I. Schneiderman Edward A. Sheriff W. Scott Monks Terra D. Vincent-Hall
Military personnel frequently incur occupational exposure to jet fuels, which may have long-term health effects. While persistent immunotoxicity and short-term effects such as acute respiratory irritation are well-documented, the extent to which long-term occupational jet fuel exposure contributes to respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) remain unclear. To address this question and assess other possible health effects, the Department of Veterans Affairs is conducting the LIFE Study, a retrospective cohort of more than 1.3 million US military Veterans who entered service in 1995 or later. The cohort includes all Veterans who worked in military occupations identified as involving probable jet fuel exposure and a random sample of non-exposed. The current analysis examined a subset of more than 800,000 Veterans with administrative records of healthcare encounters both during and after their service careers. Time spent working in fuel-exposed occupations was used as a proxy for duration of jet fuel exposure and was categorized into quintiles. Asthma and COPD cases were identified using ICD-9 and -10 diagnosis codes in the administrative encounters data. Cox proportional hazards models with time-varying exposure were used to estimate the effect of exposure duration on asthma and COPD risk. Models were adjusted for demographics, documented smoking and alcohol use, and military service characteristics (i.e., service branch, deployment, length of service, and rank). Results showed a small but significantly elevated risk of COPD in Veterans with approximately 3 to 6 years of exposure duration and of asthma with ≥7 years compared to those with no identified exposure. The LIFE Study may provide a model for cumulative assessment of military occupational exposures, and findings may inform policy changes around hazard control and Veterans’ benefits. Future work will analyze other respiratory diseases and those of other body systems.