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Familial associations of Alzheimer disease and essential tremor with Parkinson disease
Author(s) -
Costello S.,
Bordelon Y.,
Bronstein J.,
Ritz B.
Publication year - 2010
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.2010.02974.x
Subject(s) - medicine , proband , first degree relatives , disease , family history , hazard ratio , family aggregation , cohort , essential tremor , pediatrics , population , psychiatry , confidence interval , biochemistry , chemistry , environmental health , gene , mutation
Background: We constructed a cohort of first‐degree relatives of participants in a population‐based case–control study of Parkinson disease (PD) and compared the occurrence of Alzheimer disease (AD) and essential tremor (ET) in relatives of PD cases and controls. Methods: We relied on proband interviews to assess family history in 372 probands with incident PD confirmed by a movement disorder specialist and 404 controls from three rural California counties. Results: Overall, for the 2980 first‐degree relatives of PD cases, the risk of AD was not increased compared with the 2981 relatives of controls. But relatives of younger onset PD cases (≤60 years of age) were three times more likely to have received an AD diagnosis [hazard ratios (HR): 2.86; 95%CI: 1.44, 5.71]. Our data also suggest that some relatives of PD probands might be at a slightly increased risk of receiving an ET diagnosis, especially relatives of tremor dominant cases (HR: 1.69; 95%CI 0.99, 2.88), younger onset cases (HR: 2.03; 95%CI 0.93, 4.44), and male relatives (HR: 2.31; 95%CI 1.13, 4.73). In addition, fathers of cases were almost 15 years younger than fathers of controls when diagnosed with ET. Results were stable in sensitivity analyses. Conclusion: Our study suggests a familial susceptibility to AD amongst first‐degree relatives of younger onset PD cases.