title: Parkinson's disease and cancer: A register-based family study.
abstract: We wanted to compare cancer incidence rates between Parkinson's disease (PD) patients and persons without PD, as well as between siblings of these groups. We conducted a family-based matched cohort study based on nationwide Swedish health registries and the Swedish Multi-Generation Register. We assessed risk of incident cancer in PD patients (n = 11,786) during 1964-2009 versus a matched cohort of PD-free individuals (n = 58,930) and in siblings of PD patients (n = 16,841) versus siblings of PD-free individuals (n = 84,205). Hazard ratios with 95% confidence intervals were estimated using Cox proportional hazards regression. Cancer occurrence was slightly higher in PD patients than in PD-free individuals (hazard ratio (HR) = 1.05, 95% confidence interval (CI): 1.00, 1.10), largely because of cancers arising within 1 year before or after the index date for PD, but risk of smoking-related cancers was lower (HR = 0.87, 95% CI: 0.79, 0.96). PD patients had a higher risk of melanoma both up to 1 year before the PD index date (HR = 1.53, 95% CI: 1.23, 1.91) and from 1 year after the index date onward (HR = 1.46, 95% CI: 1.01, 2.10). In the sibling comparison, cancer occurrence was largely similar. These results indicate that melanoma risk is higher among PD patients and that mechanisms other than familial ones explain the association.
authors.forename: Karin
authors.initials: K
authors.lastname: Wirdefeldt
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Weibull
authors.forename: Honglei
authors.initials: H
authors.lastname: Chen
authors.forename: Freya
authors.initials: F
authors.lastname: Kamel
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundholm
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004522:Educational Status; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D010300:Parkinson Disease / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012042:Registries; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
keywords: Parkinson's disease; cancer; cohort studies; hazard ratio; siblings