Title:  Modeling the Incidence Rates of Positive Drug Tests in the Air Force 1996-1999

Presenter:  Chuck McGhee, Ph.D., Tarrant County Public Health Department, Fort Worth, TX

The Air Force noticed an increase in positive drug tests in 1999.  They had previously changed the criteria for random drug testing.  This study looked at the random drug tests from October 1996 to September 1999.  The goal was to predict positive drug tests and determine the trend of positive drug tests.  Logistic regression was used to determine risk factors for positive drug tests.  Cumulative incidence rates were tested for linear trend.  Several variables were significant (status, age, rank, transfer & turn around time, and ethnicity) in the multivariate model.  The cumulative incidence rate for the 36-month time period increased by 0.05 and was significant.  The conclusions drawn from this were to continue monitoring the transport of samples for testing and to target the younger enlisted personnel in all service groups (active, reserve, and national guard) with more interventions.