Understanding illicit drug use patterns through wastewater analysis

Illicit drug use is a perennial societal problem that has serious ramifications on the health and socioeconomic well-being of a society. Its identification and estimation in communities is difficult because of the privacy laws and doctor-patient confidentiality agreements, which may limit the availability of reports and data. Various analytical strategies and research methodologies rely on surveys and reports from health and other government agencies. In this study, we employ a relatively new approach called "wastewater epidemiology" to study the patterns of cocaine use in Belgium. We compiled and analyzed census data and previously published water quality data from 37 wastewater treatment plants across Belgium. Using Pearson correlation and stepwise multiple regression analyses, we examined the relationship of cocaine loads at the treatment plants with service coverage, and the population age group, education, and employment. Our results show strong correlations (p <0.001) between cocaine loads and served population size (R2 = 0.89), younger population (< 18 years old, R2 = 0.89), manual labor (blue collar jobs, RR2 = 0.88), and tertiary level education (R2 = 0.88). Interestingly, cocaine loads were positively correlated with higher education level (Coeff. = 2.0, p < 0.0001); and negatively correlated with lower education level (Coeff. = -47.6, p = 0.02). Our findings suggest that wastewater epidemiology can potentially be used as a complementary tool to existing survey-based studies of illicit drug consumption in society. Further, this method provides real-time data and a non-invasive alternative to understanding the patterns of drug use in communities.