Abstract
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 language | English (US) |
---|---|
Pages (from-to) | 1607-1614 |
Number of pages | 8 |
Journal | Movement Disorders |
Volume | 22 |
Issue number | 11 |
DOIs | |
State | Published - Aug 15 2007 |
Keywords
- Cohort study
- Essential tremor
- Familial aggregation
- Genetics
- Parkinson's disease
ASJC Scopus subject areas
- Neurology
- Clinical Neurology