(CN) – Using cellphone data and sewage testing, researchers in Norway have developed a novel approach for measuring drug-use patterns that overcomes limitations that have affected previous efforts to evaluate consumption of pharmaceutical and illicit substances.
While monitoring drug use has often relied on self-reported information, survey data lacks accuracy as respondents are not always reliable. Another common approach involves testing communities’ wastewater for pharmaceutical and illicit substances and their metabolites, but this method is also subject to conflicting variables.
To address the uncertainty fostered by these tactics, a team of researchers cross-referenced samples from a sewage catchment area and local population levels with cellphone data, which allowed them to accurately measure drug-use patterns in Oslo, Norway, from June to July 2016.
The team, led by Kevin V. Thomas of the Norwegian Institute for Water Research, compared local population levels with anonymous cellphone data from the telecommunications company Telenor.
“Once we found a collaborator in Telenor the process was quite straightforward. They applied for the appropriate approvals to collect the anonymous data we needed and they collected the data for the period we performed the study,” Thomas told Courthouse News in an email. “The biggest challenge in performing these types of studies is getting a mobile phone operator to collaborate.”
After reviewing the data, the researchers found that the local population could fluctuate by more than 40 percent within a 24-hour period.
“We were surprised that the peak daily population within the catchment was 3 p.m. because for some reason we assumed it would be much earlier in the day,” Thomas said. “We assume this fluctuation is due to commuters into the catchment.
“What also surprised us was the much lower populations during the weekend. This is really important for example when we study daily trends in drug use over a week where we have in the past normalized our data to a static population for all days of the week.”
After accounting for population fluctuations, the team found that pharmaceutical use remained fairly consistent, while illicit substance consumption increased from June to July. The use of the drug Ecstasy spiked on the weekends.
The findings suggest that cellphone data could allow public health officials, law enforcement and epidemiologists to improve their understanding of drug-use trends, according to the team.
“Whilst study of drug-use patterns has led to quantifying the extent of the use of a specific drug in society, there is clear potential to develop the approach to other measures of exposure and how populations respond to the stressors,” Thomas said.
The study was published Wednesday in the journal Environmental Science & Technology.