Familial aggregation of Parkinson's disease: a population-based case-control study in Europe. EUROPARKINSON Study Group.
OBJECTIVE
To investigate the familial aggregation of PD in a large collaborative population-based case-control study.


BACKGROUND
Most previous case-control studies of the familial aggregation of PD have been hospital- or clinic-based.


METHODS
We included 219 prevalent cases ascertained in three European populations (centers), using a two-phase design consisting of screening and examination by a neurologist. Each case was matched by age, sex, and center to three controls drawn from the same populations (n = 657). Presence of PD among first-degree relatives (parents and siblings) was determined using the family history approach for 175 cases and 481 controls.


RESULTS
Overall, a positive family history (at least one parent or sibling affected by PD) was reported in 10.3% of patients and 3.5% of controls (odds ratio [OR] = 3.2; 95% confidence interval [CI] = 1.6 to 6.6). A similar association was observed when analyses were restricted to nondemented patients and controls (OR = 3.9; 95% CI = 1.7 to 8.7) or to newly diagnosed patients (OR = 3.3; 95% CI = 0.9 to 11.9). We found a significant trend of increasing risk with increasing number of affected relatives (p = 0.003). Analyses stratified by age showed a stronger association for younger PD patients (OR = 7.6; 95% CI = 1.5 to 38.9) than for older patients (OR = 2.5; 95% CI = 1.1 to 5.7).


CONCLUSIONS
In this large sample of prevalent PD patients and population-matched controls, PD significantly aggregates in families, with the strength of the association being age-dependent. Therefore, familial factors, which can be genetic, environmental, or both, play a role in PD.
Elbaz
A
A
INSERM U 360, Recherches Epidémiologiques en Neurologie et Psychopathologie, Hôpital de la Salpêtrière, Paris, France. elbaz@ccr.jussieu.fr
Grigoletto
F
F
Baldereschi
M
M
Breteler
M M
MM
Manubens-Bertran
J M
JM
Lopez-Pousa
S
S
Dartigues
J F
JF
Alpérovitch
A
A
Tzourio
C
C
Rocca
W A
WA
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005060:Europe / Q000453:epidemiology; D005828:Genetics, Population; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology* / Q000235:genetics*