title: Time trends in single versus concomitant neck and back pain in Finnish adolescents: results from national cross-sectional surveys from 1991 to 2011.
abstract: BACKGROUND
  Previous studies, in late 20th century, suggest an increase in the prevalence of neck pain and low back pain among children and adolescents, when neck and low back pain were studied separately. This study investigated time trends in adolescent spinal pain between 1991 and 2011 by classifying pain into the following three classes: neck pain alone, low back pain alone, and concomitant neck and low back pain.
  
  
  METHODS
  Representative samples of 12 to 18-year-old Finns were sent a questionnaire in 1991, 1999, 2001, 2003, 2005, 2007, 2009 and 2011. Information was gathered about the frequency of neck and low back pain with a six-month recall period. Statistical methods used included descriptive analysis, and generalized linear models.
  
  
  RESULTS
  The total number of respondents in these eight comparable cross-sectional surveys was 51 044 with a response proportion of 64%. The prevalence of concomitant neck and low back pain showed a steady increase from 1991 to 2009/2011; the prevalence almost quadrupled among 12-14-year-olds girls (from 2% to 7.5%), and more than doubled among 12-14-year-old boys (from 1.6% to 3.8%), and among 16-18-year old boys (from 4.2 to 9.9%) and girls (6.9% to 15.9%). The prevalence of neck pain alone only increased in the 1990s (e.g. among 16-18-year-old girls 22.9% in 1991, 29.2% in 1999, and 29.5% in 2011), while the prevalence of low back pain alone remained relatively constant during the last two decades (e.g. among 16-18-year-old girls 4% in 1991, 3.1% in 1999, and 3.7% in 2011).
  
  
  CONCLUSIONS
  Concomitant neck and low back pain has constantly increased in the last two decades among adolescents, while single neck pain has only increased in the 1990s. Single low back pain has remained relatively constant. Thus, earlier detected increase in low back pain in the 1990s was explained by the increase in concomitant neck and low back pain. Differences in the time trends in the three pain conditions might suggest, at least partly, different risk factors and aetiology for single- and multisite spinal pain among adolescents. This hypothesis needs further investigations.
authors.affiliation: Department of Physical and Rehabilitation Medicine, Hatanpää Hospital, Hatanpäänkatu 24, PO Box 437, Tampere 33101, Finland. minna.stahl@tampere.fi.
authors.forename: Minna Kristiina
authors.initials: MK
authors.lastname: Ståhl
authors.forename: Ashraf Abdel Salam
authors.initials: AA
authors.lastname: El-Metwally
authors.forename: Arja Hannele
authors.initials: AH
authors.lastname: Rimpelä
mesh_terms: D000293:Adolescent; D001416:Back Pain / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D015897:Comorbidity / Q000639:trends; D003430:Cross-Sectional Studies / Q000639:trends; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D019547:Neck Pain / Q000175:diagnosis* / Q000453:epidemiology*; D010147:Pain Measurement / Q000639:trends*; D013997:Time Factors