Alzheimer's disease, Parkinson's disease and essential tremor: three common degenerative diseases with shared mechanisms?

摘要

Costello et al. [1] conducted a population-based family study, comparing Parkinson's disease (PD) families to control families. The authors relied on proband interviews to assess the family history of essential tremor (ET) and Alzheimer"s disease (AD) amongst 2980 first-degree relatives of 372 PD probands and 2981 first-degree relatives of 404 control probands. The probands were living in three counties in California. Cox proportional hazards models were used to calculate hazards ratios (HRs) for developing AD or ET amongst first-degree relatives. Although the overall risk of AD was not increased in PD-relatives compared with control-relatives (adjusted HR = 1.02, P = 0.93), relatives of younger onset PD cases were three times more likely than relatives of control probands to have AD (adjusted HR = 2.86, P = 0.003). The risk of ET was marginally increased in relatives of PD cases (adjusted HR = 1.44, P = 0.13), relatives of tremor dominant PD cases (adjusted HR = 1.69, P = 0.05) and relatives of younger onset PD cases (adjusted HR = 2.03, P = 0.08) when compared with relatives of controls.