Environmental factors increase mortality risk among injection drug users in Tijuana, Mexico
R.A. Pollini1, R. Lozada2, D. Abramovitz1, A. Vera1, C. Magis-Rodriguez3, S.A. Strathdee1
1University of California San Diego, La Jolla, United States, 2Prevencasa A.C., Tijuana, Mexico, 3Centro Nacional para la Prevencion y Control de SIDA, Mexico City, Mexico
drug users (IDUs) have high mortality rates.
We examined individual- and environmental-level predictors of mortality among
IDUs in Tijuana, Mexico.
in April 2006, IDUs were recruited using respondent driven sampling (RDS) and
underwent semi-annual surveys and testing for HIV, TB and syphilis. Mortality was ascertained by witness reports,
family member confirmation and/or government mortality databases and confirmed
by death certificate when available. Cox regression with RDS adjustment was
used to identify predictors of mortality.
Results: Of 1,056
IDUs, 953 (90.2%) had at least one follow-up visit. Of these 953, 48 (5.0%) tested HIV+ at
baseline or follow-up and 45 (4.7%) died during follow-up (2.5 per 100 person
years; 95% CI: 1.73-3.16). Preliminary
data indicate cause of death as follows:
36% overdose, 22% homicide, 13% other injuries, 13% AIDS-related
infections, 7% other causes, 7% undetermined.
Independent predictors of mortality were HIV infection (adjusted hazard ratio
(adjHR) 9.84; 95% CI: 4.18-23.15), number of incarcerations (adjHR: 1.03; 95%
CI: 1.01-1.05), injecting drugs in vacant lots (adjHR: 5.89; 95% CI: 1.82-
19.11), injecting heroin powder vs. black tar (adjHR: 11.27; 95% CI: 2.87-44.35),
and injecting drug combinations the first time they injected (adjHR: 3.53; 95%
expected, HIV infection contributed significantly to mortality risk among IDUs
in Tijuana. However, environmental
factors including incarceration, location of injection and heroin type also increased
mortality risk, indicating that structural interventions are needed to reduce
IDU mortality. Overdose was the leading
cause of death, suggesting that overdose prevention and response interventions
should be prioritized in Tijuana.
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