title: Is lower socioeconomic status associated with more advanced thyroid cancer stage at presentation? A study in two Canadian centers.
abstract: BACKGROUND
  Some studies have shown a higher incidence of thyroid cancer in patients with insurance coverage and higher socioeconomic status (SES), and a higher thyroid cancer stage in patients with lower SES, suggesting SES-related health disparity in thyroid cancer. However, it is not known if the same is evident under a universal healthcare system such as that in Canada.
  
  
  METHODS
  We used data from the Canadian Thyroid Cancer Consortium, a large thyroid cancer registry that collects data from two major thyroid cancer referral centers (London, Ontario, and Halifax, Nova Scotia). We included patients who presented with thyroid cancer between 1998 and 2011. We determined age at presentation, sex, and thyroid cancer status using the American Joint Committee on Cancer (AJCC) staging criteria. Individuals' postal codes were used to retrieve data from the Canadian census for the years 1996, 2001, and 2006 to approximate household income. Ordered logistic regression was used to determine odds ratios of presenting with more advanced stage thyroid cancer as they relate to income, age, and sex.
  
  
  RESULTS
  We included 1701 patients: 1334 cases from London and 367 from Halifax. Thyroid cancer was diagnosed more frequently in the higher SES groups (p<0.001). Compared to patients in the top income quintile, patients in the lowest and second-lowest income quintiles had significantly higher odds of having more advanced stage thyroid cancer at presentation (OR 1.58, p=0.002; 1.37, p=0.024 respectively).
  
  
  CONCLUSIONS
  Our study suggests that, similar to countries that lack a universal healthcare system, health disparity in thyroid cancer also exists in Canada. It appears that while thyroid cancers were diagnosed more frequently in Canadian patients of higher SES, Canadian patients in the lower SES groups had more advanced stage thyroid cancer at presentation.
authors.affiliation: 1 Department of Medicine, Schulich School of Medicine and Dentistry, Western University , London, Canada .
authors.forename: Stephanie
authors.initials: S
authors.lastname: Siu
authors.forename: James Ted
authors.initials: JT
authors.lastname: McDonald
authors.forename: Murali
authors.initials: M
authors.lastname: Rajaraman
authors.forename: Jason
authors.initials: J
authors.lastname: Franklin
authors.forename: Terri
authors.initials: T
authors.lastname: Paul
authors.forename: Irina
authors.initials: I
authors.lastname: Rachinsky
authors.forename: Deric
authors.initials: D
authors.lastname: Morrison
authors.forename: S Ali
authors.initials: SA
authors.lastname: Imran
authors.forename: Steven
authors.initials: S
authors.lastname: Burrell
authors.forename: Robert
authors.initials: R
authors.lastname: Hart
authors.forename: Al
authors.initials: A
authors.lastname: Driedger
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Badreddine
authors.forename: John
authors.initials: J
authors.lastname: Yoo
authors.forename: Martin
authors.initials: M
authors.lastname: Corsten
authors.forename: Stan
authors.initials: S
authors.lastname: Van Uum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D005260:Female; D054625:Healthcare Disparities; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012042:Registries; D012923:Social Class; D012959:Socioeconomic Factors; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult