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Study of possible factors associated with age of onset in essential tremor

Authors

  • Elan D. Louis MS, MD,

    Corresponding author
    1. Gertrude H. Sergievsky Center, Columbia University, New York, New York, USA
    2. Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA
    3. Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
    • Unit 198, Neurological Institute, 710 West 168th Street, New York, NY 10032
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  • Ruth Ottman PhD

    1. Gertrude H. Sergievsky Center, Columbia University, New York, New York, USA
    2. Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
    3. Epidemiology of Brain Disorders Research Department, New York State Psychiatric Institute, New York, New York, USA
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Abstract

Factors associated with the age of onset of essential tremor (ET) have not been studied in detail. Identification of modifiable factors could lead to strategies to delay disease onset and identification of nonmodifiable factors would be useful while counseling at risk individuals. The objective of this study was to identify factors associated with age of onset of tremor in ET. One hundred ninety-five ET cases were enrolled in an environmental epidemiological study. Clinical questionnaires included questions on age of onset, demographics (age, sex, race, education), early-life exposures (birth order, childhood household size), exposures prior to tremor onset (head trauma, well water, rural living, estrogen replacement therapy), and family history. In unadjusted analyses, age of onset was associated with family history of tremor (40.9 ± 22.0 years for cases with a family history of tremor vs. 57.3 ± 18.4 years for cases without a history; P < 0.001), history of head trauma, younger current age, greater tremor severity, and white race. Ninety-one percent of cases with onset before age 20 years had a family history of tremor. Age ofonset was not associated with other variables of interest (e.g., sex, well water, rural living). In an adjusted linear regression model, age of tremor onset was strongly associated with family history of tremor (P < 0.001). The familial form of ET is characterized by an earlier age of onset than the sporadic form. This study did not detect any other exposures that modified the age of onset of ET. Follow-up studies are needed to examine additional factors of potential interest. © 2006 Movement Disorder Society

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