Environmental, medical, and family history risk factors for Parkinson's disease: A new England-based case control study

Controversy persists about the etiology of Parkinson's disease (PD), Pestic ides, herbicides, well-water consumption, head injury, and a family history of PD have been reported as risk factors for PD. The purpose of this study was to (1) investigate the impact of environmental factors on PD risk (2) estimate the chronology, frequency, and duration of those exposures associa ted with PD; and (3) investigate the effects of family history on PD risk, One-hundred and forty PD cases were recruited from Boston University Medica l Center. The control group was composed of 147 friends and in-laws of PD p atients. Environmental, medical, and family history data were obtained by s tructured interview from each participant for events recalled prior to PD o nset for cases, or corresponding censoring age for controls (mean age = 56 years of age for each group), A traditional stratified analysis, adjusting for birth cohort and sex, was employed, Four factors were associated with i ncreased risk for PD: (1) head injury (OR=6.23, confidence interval [CI]: 2 .58-15.07); (2) family history of PD (OR=6.08, CI: 2.35-15.58);.(3) family history of tremor (OR=3.97, CI: 1.17-13.50); and (4) history of depression (OR=3.01, CI: 1.32-6.88). A mean latency of 36.5 (SE=2.81) years passed bet ween the age of first reported head injury and PD onset, A mean latency of 22 (SE=2.66) years passed between the onset of the first reported symptoms of depression and onset of PD, Years of education, smoking, and well-water intake were inversely associated with PD risk. PD was not associated with e xposure to pesticides or herbicides, These findings support the role of bot h environmental and genetic factors in the etiology in PD, The results are consistent with a multifactorial model, Am. J, Med, Genet. (Neuropsychiatr, Genet,) 88:742-749, 1999, (C) 1999 Wiley-Liss, Inc.