[1] James A Haley Vet Hosp, Dept Med Pulm Crit Care & Occupat Med, Tampa, FL 33612 USA
[2] Tampa Gen Hosp, Dept Med, Div Pulm Crit Care & Occupat Med, Tampa, FL 33606 USA
[3] Univ S Florida, Hlth Sci Ctr, Dept Epidemiol & Biostat, Tampa, FL USA
[4] Univ Tennessee, Memphis, TN USA
[5] Baptist Hosp, Dept Med, Memphis, TN USA