title: The association between age of onset of opioid use and comorbidity among opioid dependent patients receiving methadone maintenance therapy.
abstract: Opioid use disorder (OUD) affects approximately 21.9 million people worldwide. This study aims to determine the association between age of onset of opioid use and comorbid disorders, both physical and psychiatric, in patients receiving methadone maintenance treatment (MMT) for OUD. Understanding this association may inform clinical practice about important prognostic factors of patients on MMT, enabling clinicians to identify high-risk patients.
  
  
  
  This study includes data collected between June 2011 and August 2016 for the Genetics of Opioid Addiction research collaborative between McMaster University and the Canadian Addiction Treatment Centers. All patients were interviewed by trained health professionals using the Mini-International Neuropsychiatric Interview and case report forms. Physical comorbidities were verified using patients' electronic medical records. A multi-variable logistic regression model was constructed to determine the strength of the association between age of onset of opioid use and the presence of physical or psychiatric comorbidity while adjusting for current age, sex, body mass index, methadone dose and smoking status.
  
  
  
  Data from 627 MMT patients with a mean age of 38.8 years (SD = 11.07) were analyzed. Individuals with an age of onset of opioid use younger than 18 years were found to be at higher odds for having a physical or psychiatric comorbid disorder compared to individuals with an age of onset of opioid use of 31 years or older (odds ratio 2.94, 95% confidence interval 1.20, 7.19, p = 0.02). A significant association was not found between the risk of having a comorbidity and an age of onset of opioid use between 18 and 25 years or 26 and 30 years, compared to an age of onset of opioid use of 31 years or older.
  
  
  
  Our study demonstrates that the younger one begins to use opioids, the greater their chance of having a physical or psychiatric co-morbidity. Understanding the risk posed by an earlier onset of opioid use for the later development of comorbid disorders informs clinical practice about important prognostic predictors and aids in the identification of high-risk patients.
authors.affiliation: Michael Degroote School of Medicine, McMaster University, Hamilton, Canada.
authors.forename: Leen
authors.initials: L
authors.lastname: Naji
authors.affiliation: St. George's University of London, London, UK.|Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors.forename: Brittany Burns
authors.initials: BB
authors.lastname: Dennis
authors.affiliation: St. George's University of London, London, UK.
authors.forename: Monica
authors.initials: M
authors.lastname: Bawor
authors.affiliation: Canadian Addiction Treatment Centres, Richmond Hill, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Varenbut
authors.affiliation: Canadian Addiction Treatment Centres, Richmond Hill, Canada.
authors.forename: Jeff
authors.initials: J
authors.lastname: Daiter
authors.affiliation: Canadian Addiction Treatment Centres, Richmond Hill, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Plater
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Pare
authors.affiliation: Canadian Addiction Treatment Centres, Richmond Hill, Canada.|Northern Ontario School of Medicine, Sudbury, ON, Canada.
authors.forename: David C
authors.initials: DC
authors.lastname: Marsh
authors.affiliation: Canadian Addiction Treatment Centres, Richmond Hill, Canada.|Department of Medicine, Hamilton General Hospital, Hamilton, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Worster
authors.affiliation: Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada.
authors.forename: Dipika
authors.initials: D
authors.lastname: Desai
authors.affiliation: Peter Boris Centre for Addictions Research, Hamilton, Canada.|Department of Psychiatry and Behavioural Neuroscience, McMaster University, 100 West 5th Street, Hamilton, ON, L8N 3K7, Canada.
authors.forename: James
authors.initials: J
authors.lastname: MacKillop
authors.affiliation: Departments of Pediatrics and Anesthesia, McMaster University, Hamilton, Canada.|Centre for Evaluation of Medicine, St Joseph's Healthcare, Hamilton, Canada.|Biostatistics Unit, Father Sean O'Sullivan Research Centre, St Joseph's Healthcare, Hamilton, Canada.
authors.forename: Lehana
authors.initials: L
authors.lastname: Thabane
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada. samaanz@mcmaster.ca.|Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada. samaanz@mcmaster.ca.|Peter Boris Centre for Addictions Research, Hamilton, Canada. samaanz@mcmaster.ca.|Department of Psychiatry and Behavioural Neuroscience, McMaster University, 100 West 5th Street, Hamilton, ON, L8N 3K7, Canada. samaanz@mcmaster.ca.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Samaan
mesh_terms: D000328:Adult; D017668:Age of Onset; D000701:Analgesics, Opioid / Q000009:adverse effects; D015897:Comorbidity; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D058850:Opiate Substitution Treatment / Q000706:statistics & numerical data*; D009293:Opioid-Related Disorders / Q000188:drug therapy / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone
keywords: Methadone; Opioid substitution treatment; Opioid use disorder; Risk prediction; Substance use