RISK-FACTORS FOR AND KNOWLEDGE OF MYCOBACTERIUM-TUBERCULOSIS INFECTION AMONG DRUG-USERS IN SUBSTANCE-ABUSE TREATMENT

Objective, To determine the prevalence, incidence and risk factors for Mycobacterium tuberculosis infection, as well as to assess TB knowled ge and attitudes, among a group of known drug users in a city with low TB incidence (11.3 per 100 000 in 1995). Methods. Patients of an urba n drug treatment facility enrolled in opioid substitution, opioid anta gonist and other drug treatment programs were screened for TB, includi ng tuberculin skin testing and standardized data collection on TB risk factors. A subsample of clients was interviewed about TB knowledge an d attitudes. Results. Between I June 1995 and 31 May 1996, 1055 indivi duals were screened. The prevalence of infection was 15.7% (CI: 13.2-1 8.2%). PPD positivity was associated with older age (per annum, OR=1.0 8, CI: 1.05-1.11), non-white race (OR=2.81, CI: 1.72-4.60), foreign bi rth (OR = 4.24, CI: 2.35-7.62) and a history of injecting drug use (OR = 1.89, CI: 1.14,3.12). The incidence of infection teas 2.9 per 100 p erson-years (CI:1.8-4.7). Thirty-two per cent of 79 drug users intervi ewed about TB knowledge and attitudes thought TB could be prevented by bleaching or not sharing needles/syringes. Fifty-one per cent thought anyone with a positive TB skin test teas contagious. Conclusion. M. t uberculosis infection was common in this population and associated wit h injecting drugs and several demographic factors. The incidence of ne w infection was relatively low. In this non-endemic environment, the d etection and treatment of latent infection are important aspects of TB control. Misconceptions about TB transmission were also widespread il l this population.. Drug treatment programs can play a Key role by und ertaking screening programs that educate about TB and identify infecte d subjects who would benefit from preventive therapy.