Social and structural factors associated with substance use within the support network of adults living in precarious housing in a socially marginalized neighborhood of Vancouver, Canada

• Published in: PloS one 2019-09, Vol.14 (9), p.e0222611
• Main Authors: Knerich, Verena, Jones, Andrea A, Seyedin, Sam, Siu, Christopher, Dinh, Louie, Mostafavi, Sara, Barr, Alasdair M, Panenka, William J, Thornton, Allen E, Honer, William G, Rutherford, Alexander R
• Format: Article
• Language: English
• Subjects: Adult; Adults; Alcoholic beverages; Alcoholism - epidemiology; Alcoholism - etiology; Alcoholism - psychology; Analysis; Biology and Life Sciences; British Columbia - epidemiology; Cannabis; Clusters; Cocaine; Cocaine Smoking - epidemiology; Computer and Information Sciences; Control; Correlation analysis; Crack (Drug); Demographics; Dispersion; Drinking (Alcoholic beverages); Drug abuse; Earth Sciences; Female; Health; Health risks; Heroin; Hotels; Hotels & motels; Hotels and motels; Housing; Humans; Longitudinal Studies; Male; Marijuana; Marijuana Abuse - epidemiology; Marijuana Abuse - etiology; Marijuana Abuse - psychology; Medicine and Health Sciences; Methamphetamine; Network architectures; Network topologies; Occupancy; Permutations; Physical Sciences; Powders (Particulate matter); Psychological aspects; Residence Characteristics; Risk factors; Risk management; Risk reduction; Smoking - epidemiology; Smoking - psychology; Social interactions; Social Marginalization - psychology; Social networks; Social organization; Social Sciences; Social Support; Socioeconomic Factors; Substance abuse; Substance use; Substance-Related Disorders - epidemiology; Substance-Related Disorders - etiology; Substance-Related Disorders - psychology; Tobacco; Topology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0222611

The structure of a social network as well as peer behaviours are thought to affect personal substance use. Where substance use may create health risks, understanding the contribution of social networks to substance use may be valuable for the design and implementation of harm reduction or other interventions. We examined the social support network of people living in precarious housing in a socially marginalized neighborhood of Vancouver, and analysed associations between social network structure, personal substance use, and supporters' substance use. An ongoing, longitudinal study recruited 246 participants from four single room occupancy hotels, with 201 providing social network information aligned with a 6-month observation period. Use of tobacco, alcohol, cannabis, cocaine (crack and powder), methamphetamine, and heroin was recorded at monthly visits. Ego- and graph-level measures were calculated; the dispersion and prevalence of substances in the network was described. Logistic mixed effects models were used to estimate the association between ego substance use and peer substance use. Permutation analysis was done to test for randomness of substance use dispersion on the social network. The network topology corresponded to residence (Hotel) with two clusters differing in demographic characteristics (Cluster 1 -Hotel A: 94% of members, Cluster 2 -Hotel B: 95% of members). Dispersion of substance use across the network demonstrated differences according to network topology and specific substance. Methamphetamine use (overall 12%) was almost entirely limited to Cluster 1, and absent from Cluster 2. Different patterns were observed for other substances. Overall, ego substance use did not differ over the six-month period of observation. Ego heroin, cannabis, or crack cocaine use was associated with alter use of the same substances. Ego methamphetamine, powder cocaine, or alcohol use was not associated with alter use, with the exception for methamphetamine in a densely using part of the network. For alters using multiple substances, cannabis use was associated with lower ego heroin use, and lower ego crack cocaine use. Permutation analysis also provided evidence that dispersion of substance use, and the association between ego and alter use was not random for all substances. In a socially marginalized neighborhood, social network topology was strongly influenced by residence, and in turn was associated with type(s) of substance use. Associations between per