title: Analgesic use: a predictor of chronic pain and medication overuse headache: the Head-HUNT Study.
abstract: OBJECTIVE
  To examine the relation between analgesic use at baseline and the subsequent risk of chronic pain (> or =15 days/month) and the risk of analgesic overuse.
  
  
  METHODS
  In total, 32, 067 adults reported the use of analgesics in 1984 to 1986 and at follow-up 11 years later (1995 to 1997). The risk ratios (RR) of chronic pain and RR of analgesic overuse in the different diagnostic groups (i.e., migraine, nonmigrainous headache, neck pain, and low-back pain) were estimated in relation to analgesic consumption at baseline.
  
  
  RESULTS
  Individuals who reported use of analgesics daily or weekly at baseline showed significant increased risk for having chronic pain at follow-up. The risk was most evident for chronic migraine (RR = 13.3, 95% CI: 9.3 to 19.1), intermediate for chronic nonmigrainous headaches (RR = 6.2, 95% CI: 5.0 to 7.7), and lowest for chronic neck (RR = 2.4, 95% CI: 2.0 to 2.8) or chronic low-back (RR = 2.3, 95% CI: 2.0 to 2.8) pain. Among subjects with chronic pain associated with analgesic overuse, the RR was 37.6 (95% CI: 21.3 to 66.4) for chronic migraine, 14.4 (95% CI: 10.4 to 19.9) for chronic nonmigrainous headaches, 7.1 for chronic neck pain (95% CI: 5.5 to 9.2), and 6.4 for chronic low-back pain (95% CI: 4.9 to 8.4). The RR for chronic headache (migraine and nonmigrainous headache combined) associated with analgesic overuse was 19.6 (95% CI: 14.8 to 25.9) compared with 3.1 (95% CI: 2.4 to 4.2) for those without overuse.
  
  
  CONCLUSIONS
  Overuse of analgesics strongly predicts chronic pain and chronic pain associated with analgesic overuse 11 years later, especially among those with chronic migraine.
authors.affiliation: Department of Clinical Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim. john-anker.zwart@medisin.ntnu.no
authors.forename: J-A
authors.initials: JA
authors.lastname: Zwart
authors.forename: G
authors.initials: G
authors.lastname: Dyb
authors.forename: K
authors.initials: K
authors.lastname: Hagen
authors.forename: S
authors.initials: S
authors.lastname: Svebak
authors.forename: J
authors.initials: J
authors.lastname: Holmen
mesh_terms: D000328:Adult; D000700:Analgesics / Q000009:adverse effects* / Q000627:therapeutic use; D002908:Chronic Disease; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology; D006801:Humans; D017116:Low Back Pain / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology; D019547:Neck Pain / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology; D009664:Norway / Q000453:epidemiology; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology*; D011446:Prospective Studies; D012306:Risk; D019966:Substance-Related Disorders / Q000150:complications / Q000453:epidemiology*; D011795:Surveys and Questionnaires
chemical_list: D000700:Analgesics