Nonfatal cancer preceding Parkinson's disease: A case-control study

Background. We conducted a population-based case-control study to investigate the association of Parkinson's disease (PD) with preceding nonfatal cancer. Methods. We used the medical records-linkage system of the Rochester Epidemiology Project to identify all incident cases of PD in Olmsted County, MN (1976-1995). Each case was matched by age and sex to a general population control. We ascertained cancer diagnoses through medical records abstraction. Results. The frequency of any cancer was lower in cases (19.4%) than in controls (23.5%) (OR = 0.79; 95% CI = 0.49-1.27). This pattern was more pronounced in women than in men, and in patients age 71 years or younger at onset of PD than in older patients. We found an interaction between smoking and smoking-related cancers in their association with PD. Bladder cancer (OR = 0.22; 95% CI = 0.03-2.24) and breast cancer (OR = 0.20; 95% CI = 0.02-1.71) were less frequent in PD cases than in controls, whereas prostate cancer was more frequent in PD cases than in controls (OR = 1.80; 95% CI = 0.60-5.37). However, these results are based on small numbers. Conclusions. We did not find a strong association between PD and preceding nonfatal cancer. There were suggestive trends in analyses stratified by sex and age at onset of PD, and for specific cancers related to smoking or hormonal factors.