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Background: There is a lack of studies of Parkinson's disease (PD) in immigrants. Objective: To study the association between country of birth and incident PD in immigrants in Sweden versus Swedish-born individuals. Methods: Study population included all adults aged 50 years and older in Sweden (n = 2775736). PD was defined as having at least one registered diagnosis of PD in the National Patient Register. The incidence of PD in different first-generation immigrant groups versus Swedish-born individuals was assessed by Cox regression, expressed as hazard ratios (HRs) and 95% confidence intervals (CI). The models were stratified by sex and adjusted for age, geographical residence in Sweden, educational level, marital status, neighbourhood socioeconomic status and co-morbidity. Results: Totally 35833 individuals had an incident diagnosis of PD (20401 men and 15432 women). Incidence rates per 100,000 person-years were for all Swedish-born 95.9 and for all foreign-born 60.1; for all men 112.3 and for all women 73.4, with a male to female ratio of 1.53, with the highest incidence rates for the group 80–84 years of age. After adjusting for potential confounders, the overall relative risk of PD was lower in immigrant men (HR 0.78; 95% CI 0.74–0.82) and women (HR 0.92; 95% CI 0.87–0.98). Among immigrant subgroups, a higher risk of PD was found among women from Finland (HR 1.13; 95% CI 1.05–1.23). Conclusion: In general, the risk of PD was lower in first-generation immigrant men and women compared to Swedish-born. The only group with a higher risk of PD was women from Finland. [ABSTRACT FROM AUTHOR]