The development of invasive aspergillosis (IA) following BMT is a nearly universally fatal complication. Prolonged neutropenia and graft vs. host disease (GVHD) have been identified as risk factors for IA post-BMT. Because aspergillus species have been cultured from tobacco, and tobacco smoke impairs respiratory defense mechanisms, we investigated tobacco exposure as a risk factor for deveopment of IA after BMT. We performed a retrospective case-control study comparing 36 cases of definite/probable IA in patients following BMT with 72 controls matched for patient's age, sex, year of transplant, and type of transplant. Tobacco exposure was ascertained by chart review and a mailed survey to patients/next of kin. Smoking prevalence at admission for BMT was 33.3% for cases, 31.9% for controls. Prevalence of any tobacco exposure, including chewing tobacco and second-hand smoke, following BMT was 16.7% for cases, 12.5% for controls. Prolonged neutropenia (O.R. of 1.06, with 95% CI 1.00-1.12, for each additional day of neutropenia) and increased severity of GVHD (O.R. of 1.61, with 95% CI 1.12-2.40, for each increase in GVHD grade) were again confirmed to be risk factors for IA following BMT. When adjusted for multiple risk factors by multivariate logistic regression, tobacco exposure after BMT was associated with an increased odds ratio of 2.49, with 95% CI 0.86-7.16, of developing IA. This association approached statistical significance (P=0.09). Conclusions are limited due to power constraints. The relationship of tobacco exposure to the development of IA after BMT should be studied in a larger, prospective study.
Full conference title:
The American Lung Association - American Thoracic Association Conference,1998