title: Analysis of the effect of the oral contraceptive pill on clinical outcomes in women with ankylosing spondylitis.
abstract: OBJECTIVE
  There are unexplained sex-specific changes in the clinical expression of ankylosing spondylitis (AS). We sought to examine the potential effect of exogenous estrogen in the form of oral contraceptive pills (OCP) on AS initiation and severity.
  
  
  METHODS
  This cross-sectional study consisted of women with AS from the membership of the Spondylitis Association of America. Measures of disease severity included use of biological agents and hip replacement surgery, while Bath AS Functional Index (BASFI) scores served as a surrogate marker of disability. Information was obtained using a patient questionnaire on patient demographics, OCP use, pregnancy history, AS duration, medication use, and hip replacement.
  
  
  RESULTS
  There were 571 women with AS who participated in our study, consisting of 448 OCP ever-users and 123 non-OCP users. The mean age of OCP users was 42.7 yrs (± 11.5) and of non-OCP users, 48.4 yrs (± 12.1). No difference was noted in the age at initial onset of back pain. However, OCP users were significantly younger at the time of diagnosis of AS (36.5 yrs vs 39.1 yrs, p = 0.02). There were no significant differences between the 2 groups in tumor necrosis factor inhibitor or opioid use, BASFI scores, pregnancy complications, or hip surgery.
  
  
  CONCLUSIONS
  The use of exogenous estrogens in the form of OCP is not associated with a measurable effect on initiation or severity of AS. Biologic and social factors may contribute to earlier diagnosis of AS in OCP users. This is the largest study to date investigating the potential effect of exogenous estrogens in women with AS.
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH. d.mahendira@mail.utoronto.ca.
authors.forename: Dharini
authors.initials: D
authors.lastname: Mahendira
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Arane
authors.initials: A
authors.lastname: Thavaneswaran
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Adele
authors.initials: A
authors.lastname: Carty
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Nigil
authors.initials: N
authors.lastname: Haroon
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Ammepa
authors.initials: A
authors.lastname: Anton
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Laura
authors.initials: L
authors.lastname: Passalent
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Alnaqbi
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Laurie
authors.initials: L
authors.lastname: Savage
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Elin
authors.initials: E
authors.lastname: Aslanyan
authors.affiliation: From the Division of Rheumatology, University of Toronto, St. Michael's Hospital (SMH), and the Division of Rheumatology, University of Toronto, Toronto Western Hospital (TWH), Toronto, Ontario, Canada; the Division of Rheumatology, Al Ain Hospital, United Arab Emirates; and the Spondylitis Association of America (SAA), Van Nuys, California, USA.D. Mahendira, MD, MSc, FRCPC, SMH; A. Thavaneswaran, MMath, BSc; A. Carty, BPH; N. Haroon, MD, PhD, DM; A. Anton, BSc; L. Passalent, BScPT, MHSc, TWH; K.A. Alnaqbi, MD, MSc, FRCPC, TWH, and Division of Rheumatology, Al Ain Hospital; L. Savage, MS; E. Aslanyan, BA, SAA; R.D. Inman, MD, FRCPC, TWH.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Inman
mesh_terms: D000328:Adult; D017668:Age of Onset; D003276:Contraceptives, Oral / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D011795:Surveys and Questionnaires
chemical_list: D003276:Contraceptives, Oral
keywords: ANKYLOSING SPONDYLITIS; EXOGENOUS ESTROGENS; ORAL CONTRACEPTIVES