Familial aggregation of Parkinson disease in Utah: A population-based analysis using death certificates.
OBJECTIVE
To describe clustering of death from Parkinson disease (PD) in relatives in a large US study.


METHODS
We analyzed the Utah Population Database resource, which includes genealogy data of more than 2.7 million individuals linked to 519,061 individuals with a Utah death certificate (DC). We identified individuals whose DC included PD as a cause of death using ICD coding. In those individuals whose Utah DC listed PD as a cause of death, the relative risk (RR) of death with PD was determined among close and distant relatives using sex-, birth year-, and birthplace-specific rates.


RESULTS
We identified 4,031 individuals whose DC indicated PD. Among 18,127 first-degree relatives of probands with a Utah DC, the RR of death with PD was significantly increased (RR = 1.82, 95% confidence interval [CI] 1.61-2.04). The RR of death with PD was also significantly increased among 40,546 second-degree relatives with a Utah DC (RR = 1.44, 95% CI 1.29-1.60) and among 93,398 third-degree relatives with a Utah DC (RR = 1.10, 95% CI 1.03-1.18).


CONCLUSIONS
Significant evidence for excess familial clustering was observed for PD deaths. The excess familial clustering and the significantly elevated RRs for PD among close and distant relatives strongly support a genetic contribution to PD mortality. These results confirm and expand the results of previous studies of PD by quantifying the risk of PD death among more distant relatives.
Department of Neurology (R.S.), Mayo Clinic, Rochester, MN; Division of Genetic Epidemiology (L.A.C.-A.), Department of Internal Medicine, and Department of Neurology (R.S., S.P.), University of Utah School of Medicine, Salt Lake City, UT; and George E. Wahlen Department of Veterans Affairs Medical Center (L.A.C.-A.), Salt Lake City, UT.
Rodolfo
R
Savica
Department of Neurology (R.S.), Mayo Clinic, Rochester, MN; Division of Genetic Epidemiology (L.A.C.-A.), Department of Internal Medicine, and Department of Neurology (R.S., S.P.), University of Utah School of Medicine, Salt Lake City, UT; and George E. Wahlen Department of Veterans Affairs Medical Center (L.A.C.-A.), Salt Lake City, UT.
Lisa A
LA
Cannon-Albright
Department of Neurology (R.S.), Mayo Clinic, Rochester, MN; Division of Genetic Epidemiology (L.A.C.-A.), Department of Internal Medicine, and Department of Neurology (R.S., S.P.), University of Utah School of Medicine, Salt Lake City, UT; and George E. Wahlen Department of Veterans Affairs Medical Center (L.A.C.-A.), Salt Lake City, UT.
Stefan
S
Pulst