title: Trends in age disparities between younger and middle-age adults among reported rates of chlamydia, gonorrhea, and infectious syphilis infections in Canada: findings from 1997 to 2007.
abstract: BACKGROUND
  The objective was to determine trends in age disparities between reported rates of chlamydia, gonorrhea, and infectious syphilis among younger versus middle-age Canadians.
  
  
  METHODS
  We examined age- and sex-specific reported rates of chlamydia, gonorrhea, and infectious syphilis between 1997 and 2007. Sexually transmitted infection (STI) rates in the younger age group (15-29 years) were compared to the middle-age group (40-59 years) over the 11-year period. We used Poisson regression to examine trends in age-specific (younger:middle-age) rate ratios.
  
  
  RESULTS
  Between 1997 and 2007, both the number and rate of reported cases increased for all 3 nationally notifiable STIs. Although chlamydia and gonorrhea rates continued to be higher among younger adults, rates of all 3 STIs increased more dramatically among middle-age adults. Between 1997 and 2007, chlamydia rates increased by 86.8% among adults aged 15 to 29 (P <0.0001) and 165.9% among adults 40- to 59-years-old (P <0.0001). The corresponding increases for gonorrhea were 133.3% (P <0.0001) and 210.2% (P <0.0001) respectively. Infectious syphilis rates increased 5-fold among younger adults compared to an increase of 11-fold among middle-age adults (P <0.0001) since 1997. The reported rate ratios (younger:middle-age) decreased over time for chlamydia (P <0.0001), gonorrhea (P <0.0001), and syphilis (P = 0.005). Males were disproportionately represented among reported chlamydia, gonorrhea, and infectious syphilis cases, constituting 59.8%, 87.6%, and 93.0% of middle-age adult cases, respectively, in 2007.
  
  
  CONCLUSIONS
  Middle-age adults may be increasingly affected by chlamydia, gonorrhea and infectious syphilis. There is a need for sexual health information targeting Canada's middle-age adults and their health care providers.
authors.affiliation: Public Health Agency of Canada, Ottawa, Canada. Lily_Fang@phac- aspc.gc.ca
authors.forename: Lily
authors.initials: L
authors.lastname: Fang
authors.forename: Allison
authors.initials: A
authors.lastname: Oliver
authors.forename: Gayatri C
authors.initials: GC
authors.lastname: Jayaraman
authors.forename: Tom
authors.initials: T
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002170:Canada / Q000453:epidemiology; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006069:Gonorrhea / Q000453:epidemiology* / Q000517:prevention & control; D006266:Health Education; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012044:Regression Analysis; D013587:Syphilis / Q000453:epidemiology* / Q000517:prevention & control