Reid M.J.,Norwegian Institute for Water Research |
Langford K.H.,Norwegian Institute for Water Research |
Grung M.,Norwegian Institute for Water Research |
Gjerde H.,Norwegian Institute of Public Health |
And 3 more authors.
BMJ Open | Year: 2012
Objectives: A range of approaches are now available to estimate the level of drug use in the community so it is desirable to critically compare results from the differing techniques. This paper presents a comparison of the results from three methods for estimating the level of cocaine use in the general population. Design: The comparison applies to; a set of regionalscale sample survey questionnaires, a representative sample survey on drug use among drivers and an analysis of the quantity of cocaine-related metabolites in sewage. Setting: 14 438 participants provided data for the set of regional-scale sample survey questionnaires; 2341 drivers provided oral-fluid samples and untreated sewage from 570 000 people was analysed for biomarkers of cocaine use. All data were collected in Oslo, Norway. Results: 0.70 (0.36-1.03) % of drivers tested positive for cocaine use which suggest a prevalence that is higher than the 0.22 (0.13-0.30) % ( per day) figure derived from regional-scale survey questionnaires, but the degree to which cocaine consumption in the driver population follows the general population is an unanswered question. Despite the comparatively lowprevalence figure the survey questionnaires did provide estimates of the volume of consumption that are comparable with the amount of cocaine-related metabolites in sewage. Per-user consumption estimates are however highlighted as a significant source of uncertainty as little or no data on the quantities consumed by individuals are available, and much of the existing data are contradictory. Conclusions: The comparison carried out in the present study can provide an excellent means of checking the quality and accuracy of the three measurement techniques because they each approach the problem from a different viewpoint. Together the three complimentary techniques provide a wellbalanced assessment of the drug-use situation in a given community and identify areas where more research is needed.
Osthus S.,Norwegian Institute for Drug and Alcohol Research |
Amundsen E.J.,Norwegian Institute for Drug and Alcohol Research
Norsk Epidemiologi | Year: 2011
Estimates of alcohol use from a series of cross-sectional face-to-face surveys, conducted by Synovate Norway on behalf of the Norwegian institute for alcohol and drug research during the 1990s and 2000s (the Substance Use Surveys, SUS), are compared with registered sales statistics of alcohol and estimates of alcohol use from Statistics Norway's Health Surveys (HS). The results show that SUS estimates of levels and trends in alcohol use are in conflict with these alternative data sources, also when standard adjustment strategies (using post-stratification weights, controlling for background characteristics in regressions) are used. We conclude that there is likely selection on alcohol use and other factors into the SUS samples, to a higher degree than in the HS samples, which renders standard estimates of alcohol use from SUS data unreliable. In fields such as substance use research, it is notoriously difficult to measure the phenomena we are interested in, and it is especially important to assess the validity of the survey estimates with data from alternative sources.