American Journal of Epidemiology Advance Access originally published online on August 24, 2005
American Journal of Epidemiology 2005 162(7):694-703; doi:10.1093/aje/kwi263
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PRACTICE OF EPIDEMIOLOGY |
Prior Information in Behavioral Capture-Recapture Methods: Demographic Influences on Drug Injectors' Propensity to Be Listed in Data Sources and Their Drug-related Mortality
1 Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St. Andrews, United Kingdom
2 Medical Research Council Biostatistics Unit, University of Cambridge, Cambridge, United Kingdom
3 Department of Statistics and Modelling Science, University of Strathclyde, Glasgow, United Kingdom
4 Statistical Laboratory, University of Cambridge, Cambridge, United Kingdom
5 Health Protection Scotland, Glasgow, United Kingdom
6 Public Health and Health Policy Section, University of Glasgow, Glasgow, United Kingdom
7 Centre for Drug Misuse Research, University of Glasgow, Glasgow, United Kingdom
Correspondence to Dr. Sheila M. Bird, MRC Biostatistics Unit, University of Cambridge, Robinson Way, Cambridge CB2 2SR, United Kingdom (e-mail: sheila.bird{at}mrc-bsu.cam.ac.uk).
The authors present findings from a Bayesian analysis of Scotland's four primary capture-recapture data sources for 2000 that was carried out to estimate numbers of current injecting drug users by region (Greater Glasgow vs. elsewhere in Scotland), sex (male vs. female), and age group (15–34 years vs. 
35 years). A secondary goal of the analysis was to obtain Bayesian estimates and credible intervals for the demographic influences on Scotland's drug-related death rate per 100 current injectors. Incorporation of informative priors altered the models with highest posterior probability. Expert opinion on how demography influenced Scottish drug injectors' propensity to be listed in different data sources was taken into account, along with external information about European injectors' drug-related death rates and male:female ratios. Higher drug-related mortality was confirmed in older drug injectors and those outside of Greater Glasgow. Female injectors' lower drug-related death rate was not sustained beyond 34 years of age. The authors recommend that demographic influences be accommodated in behavioral capture-recapture estimation, especially when it is a prelude to secondary analysis, such as the analysis of drug-related death rates presented here.
Bayes theorem; data collection; epidemiologic methods; models, statistical; mortality; prevalence; substance abuse, intravenous
Abbreviations: DMD, Drug Misuse Database; HCV, hepatitis C virus; HPDI, highest probability density interval; IDU, injecting drug user