Impact of sex and age at onset of diabetes on mortality from ischemic heart disease in patients with type 1 diabetes
- Valma Harjutsalo, PhD1,2,3⇑,
- Christine Maric-Bilkan, PhD4,5,
- Carol Forsblom, DMSc1,2 and
- Per-Henrik Groop, MD DMSc1,2,6
- 1Folkhälsan Institute of Genetics, Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O Box 63, FIN-00014 Helsinki, Finland
- 2Division of Nephrology, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
- 3National Institute for Health and Welfare, Diabetes Prevention Unit, Helsinki, Finland
- 4Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA
- 5Women’s Health Research Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
- 6The Baker IDI Heart and Diabetes Institute, Melbourne, Australia
- Corresponding author: Valma Harjutsalo, E-mail:
Objective Our aim was to study whether ischemic heart disease (IHD) mortality among patients with type 1 diabetes (T1D) depends on the age at onset of diabetes and whether this effect is sex-specific.
Research design and methods The study examined long-term IHD-specific mortality in a Finnish population-based cohort of patients with early-onset (0-14 years) and late-onset (15-29 years) type 1 diabetes (n=17,306).
Results During 433,782 person years of follow-up, 478 IHD deaths were observed. Within the early-onset cohort, the average crude mortality rate in women was 33.3% lower compared with men while in the late-onset cohort mortality was only half of that in men. In contrast, standardized mortality ratio (SMR) was higher in women than men; 21.6 (95% CI 17.2-27.0) for women compared with 5.8 (95% CI 5.1-6.6) for men. The difference between sexes was more striking in the early-onset cohort; SMR for women was 52.8 (95% CI 36.3-74.5) and 12.1 (95% CI 9.2-15.8) for men. SMR was greater in women also in the late-onset cohort, being 15.8 (95% CI 11.8-20.7) compared with men 5.0 (95% CI 4.3-5.8). The relative risk of dying from IHD was greatest in women under 40 years and 40-60 years in the early and late-onset cohort, respectively.
Conclusion The risk of mortality from IHD is exceptionally high in women with early-onset T1D compared with women in the background population. These observations underscore the importance of identifying risk factors early in women and more aggressive treatment following diagnosis.
- Received February 14, 2013.
- Accepted August 12, 2013.
- © 2013 by the American Diabetes Association.
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