[Multifactorial etiology of idiopathic Parkinson disease. A case-control study]

The etiology of Parkinson's disease (PD) is currently thought to be due to an interplay of genetic and environmental factors. We examined (1) familial prevalences of PD and essential tremor (ET) using a control population and personal investigation; (2) comorbidity and possible traits of a altered premorbid lifestyle in PD were also investigated. Sixty-six PD patients with disease onset after 40 and before 70 years of life and 72 age- and sex-matched hospital controls with chronic diseases underwent neurologic examination and a structured interview. Allegedly symptomatic relatives were investigated personally. For the time prior to 40 years of age, PD patients reported significantly less frequent cigarette smoking overall (Odds ratio = OR 0.37); significantly less frequently a smoking duration of more than 2 years (OR 0.42); significantly less frequently an amount of more than 10 cigarettes smoked per diem (OR 0.24); they did report, however, more frequently an onset for smoking before the age of 20 (OR 3.56). Place of residence and source of drinking water during the first 15 years of life, and number of moves and journeys outside Europe before 40th year of life were not significantly different. PD patients demonstrated an increased risk of a 1st or 2nd degree relative with PD (OR 7.14) or ET (OR 3.62) compared to the control families. Congenital or perinatal abnormalities, and comorbid diseases did not suggest greater risk for PD. Stepwise logistic regression analysis yielded three variables that separated PD patients and controls most significantly, though not completely: "smoking more than 10 cigarettes per diem", "additional family members with PD", "additional family members with ET".