Population Size Estimation of Drug Users in Isfahan City (Iran) Using Network Scale-up Method in 2018

Document Type : Original Article


1 Department of Biostatistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran

2 Modeling in Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran AND School of Medicine, Center for Longitudinal and Life Course Research, School of Public Health, University of Queensland, Herston, Australia

3 Department of Biostatistics and Epidemiology, School of Health AND Regional Knowledge Hub, and WHO Collaborating Centre for HIV Surveillance, Isfahan University of Medical Sciences, Isfahan, Iran


Background: To provide prevention programs and educate drug users (DUs), the estimation of their 
population is necessary. This study aimed to estimate the population size of this hidden group in Isfahan city 
as a metropolitan in Iran using the network scale-up method (NSUM).

Methods: This cross-sectional study was performed in summer 2018 on 1000 people selected through a 
multistage sampling method based on 14 region of the municipality of Isfahan. The data collection tool was a 
questionnaire that was previously used in Dr. Banshi's national plan without any changes. The Cronbach's 
alpha value of the questionnaire was 0.826. Using correction factors such as transparency of response and the 
ratio of social network size used in previous national studies, the number of people with high-risk behaviors was 
estimated. The results were analyzed through NSUM based on survey analysis.

Findings: Among all kinds of DUs, men were the largest consumers. The prevalence of use of opium, 
cannabis, heroin/crack, stimulants, ecstasy, hallucinogens, tramadol, zolpidem, tobacco, and drug injection 
was 2983, 2342, 613, 766, 86, 268, 1185, 213, 5869, 135 in 100000 people, among individuals of over 18 
years of age. In both sexes, the prevalence of using opium and its nectar and illegal treatment with 
methadone and buprenorphine was higher in people of over 30 years of age, while the prevalence of 
consuming cannabis, ecstasy, tramadol, tobacco products, and stimulants was higher in the age group of 
18 to 30 years.

Conclusion: The results indicated that the prevalence of different DUs in Isfahan city, especially among men 
was higher than the reported average (especially in young men of 18-30 years of age). Since the prevalence of 
drug use varies based on the type of substance used among age groups, targeted preventive planning based 
on the type of drug used and age group is recommended.