Rheumatoid arthritis in women: Incidence rates in group health cooperative, seattle, washington, 1987–1989

Authors

  • Carin E. Dugowson MD, MPH,

    Corresponding author
    1. Department of Epidemiology, School of Public Health and Community Medicine, and Division of Rheumatology, Department of Medicine, University of Washington
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    • Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, 1124 Columbia Street, MP381, Seattle, WA 98104
    Search for more papers by this author
  • Thomas D. Koepsell MD, MPH,

    1. Department of Epidemiology and Department of Health Services, School of Public Health and Community Medicine, University of Washington
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    Search for more papers by this author
  • Lynda F. Voigt PhD,

    1. Department of Epidemiology, School of Public Health and Community Medicine, University of Washington
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    Search for more papers by this author
  • Linda Bley MS,

    1. Department of Epidemiology, School of Public Health and Community Medicine, University of Washington
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    Search for more papers by this author
  • J. Lee Nelson MD,

    1. Division of Clinical Research, Fred Hutchinson Cancer Research Center
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    Search for more papers by this author
  • Janet R. Daling PhD

    1. Department of Epidemiology, School of Public Health and Community Medicine, University of Washington
    2. Department of Epidemiology, and the Department of Health Services, the School of Public Health and Community Medicine, the Division of Rheumatology, the Department of Medicine, the University of Washington, and the Division of Clinical Research, the Fred Hutchinson Cancer Research Center, Seattle, Washington
    Search for more papers by this author

Abstract

As part of a prospective case-control study of newly diagnosed rheumatoid arthritis (RA) in women, we identified all cases of probable, definite, or classic RA diagnosed in 1987–1989 in 18–64-year-old women who were members of a health maintenance organization based in the Seattle, Washington area. Using both the 1958 and the 1987 American Rheumatism Association criteria for the diagnosis of RA and enrollment data from the health maintenance organization, we calculated the incidence by age and diagnostic class. Rates of RA incidence in women increased steadily with age. The incidence of probable, definite, or classic RA ranged from 13.1 per 100,000 person-years at risk for 18–29-year-old women to 82.1 per 100,000 person-years for 60–64-year-old women. The overall incidence rate, age-adjusted to the 1980 US female population, was 27.9/100,000 person-years. The overall incidence rate for definite/classic RA, age-adjusted to the 1980 US female population, was 23.9 per 100,000 person-years. When compared with adjusted rates of incidence of definite RA in Rochester, Minnesota, in 1950–1974, the incidence rates we found were 44.7% lower. Methodologic differences, changes in diagnostic criteria, and a declining incidence of RA among women over time may all be partial explanations for these results. The possible effects of reproductive factors, including oral contraceptives use, are discussed.

Ancillary