Increased risk of essential tremor in first-degree relatives of patients with Parkinson's disease

Walter A. Rocca, James H. Bower, J. Eric Ahlskog, Alexis Elbaz, Brandon R. Grossardt, Shannon K. McDonnell, Daniel J. Schaid, Demetrius M. Maraganore

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


We conducted a historical cohort study of 981 first-degree relatives of 162 patients with Parkinson's disease (PD) and of 838 first-degree relatives of 147 controls representative of the population of Olmsted County, Minnesota. In addition, we studied 2,684 first-degree relatives of 411 patients with PD referred to the Mayo Clinic. Relatives were interviewed and screened for tremor either directly or through a proxy, and those who screened positive were examined or copies of their medical records were obtained to confirm the diagnosis of essential tremor (ET). We also obtained ET information from a medical records-linkage system (family study method). In the population-based sample, the risk of ET was significantly increased for relatives of patients with onset of PD ≤ 66 years (first tertile; hazard ratio [HR] = 2.24; 95% confidence interval [95% CI] = 1.26-3.98; P = 0.006). In the referral-based sample, the risk of ET among relatives increased with younger onset of PD in patients (linear trend; P = 0.001), and was higher in relatives of PD patients with the tremor-predominant or mixed form when compared with relatives of patients with the akinetic-rigid form, and in men compared with women. These findings suggest that PD and ET may share familial susceptibility factors.

Original languageEnglish (US)
Pages (from-to)1607-1614
Number of pages8
JournalMovement Disorders
Issue number11
StatePublished - Aug 15 2007


  • Cohort study
  • Essential tremor
  • Familial aggregation
  • Genetics
  • Parkinson's disease

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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