Volume 29, Issue 13 p. 1631-1636
Research Article

Formulations of hormone therapy and risk of Parkinson's disease

Jessica I. Lundin MPH

Corresponding Author

Jessica I. Lundin MPH

Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA

Correspondence to: Jessica I. Lundin, MPH, Department of Environmental and Occupational Health Sciences, University of Washington, School of Public Health, Box 357234, Office: E-179D, 1959 NE Pacific Street, Seattle, WA 98195, E-mail: [email protected]Search for more papers by this author
Thanh G.N. Ton PhD

Thanh G.N. Ton PhD

Department of Neurology, University of Washington, Seattle, Washington, USA

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Andrea Z. LaCroix PhD

Andrea Z. LaCroix PhD

Department of Family and Preventive Medicine, University of California San Diego, La Jolla, California, USA

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W.T. Longstreth MD, MPH

W.T. Longstreth MD, MPH

Department of Neurology, University of Washington, Seattle, Washington, USA

Department of Epidemiology, University of Washington, Seattle, Washington, USA

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Gary M. Franklin MD, MPH

Gary M. Franklin MD, MPH

Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA

Department of Neurology, University of Washington, Seattle, Washington, USA

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Phillip D. Swanson MD, PhD

Phillip D. Swanson MD, PhD

Department of Neurology, University of Washington, Seattle, Washington, USA

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Terri Smith-Weller RN, MN, COHN-S

Terri Smith-Weller RN, MN, COHN-S

Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA

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Brad A. Racette MD

Brad A. Racette MD

Department of Neurology, Washington University, St. Louis, Missouri, USA

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Harvey Checkoway PhD

Harvey Checkoway PhD

Department of Family and Preventive Medicine, University of California San Diego, La Jolla, California, USA

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First published: 25 September 2014
Citations: 17

Funding agencies: This study was supported by NIH P42ES004696 and R01ES010750 (PI: H. Checkoway), and K24ES17765 (PI: B. Racette).

Relevant conflicts of interest/financial disclosures: Nothing to report.

Author roles may be found in the online version of this article.

Abstract

Hormone therapy (HT) is a class of medications widely prescribed to women in the Western world. Evidence from animal models and in vitro studies suggests that estrogen may protect against nigrostriatal system injury and increase dopamine synthesis, metabolism, and transport. Existing epidemiologic research indicates a possible reduced risk of Parkinson's disease (PD) associated with HT use. The objective of this study was to evaluate PD risk associated with specific HT formulations. Neurologist-confirmed cases and age-matched controls were identified from Group Health Cooperative (GHC) of Washington State. Final analysis included 137 female cases and 227 controls. Hormone therapy use was ascertained from the GHC pharmacy database, further classified as conjugated estrogens, esterified estrogens, and progestin. Ever use of HT formulation demonstrated a suggested elevated risk with esterified estrogen use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.0-9.8), and no risk associated with conjugated estrogen use (OR, 0.6; 95% CI, 0.6-1.3). Restricting this analysis to prescriptions that included progestin further elevated the risk associated with esterified estrogen use (OR, 6.9; 95% CI, 2.1-22.9); again, no risk was associated with conjugated estrogen use (OR, 1.7; 95% CI, 0.6-5.0). The findings from this study suggest an increase in PD risk associated with esterified estrogen use combined with progestin, and no risk associated with conjugated estrogen with progestin. These findings could have important implications for choice of HT in clinical practice. © 2014 International Parkinson and Movement Disorder Society