Fracture risk after the diagnosis of Parkinson's disease: Influence of concomitant dementia.

In an inception cohort of 196 Olmsted County, Minnesota, residents with Parkinson's disease (PD) first recognized in 1976 to 1995, we tested whether the increased risk of bone fractures is associated with concomitant dementia. Using the data resources of the Rochester Epidemiology Project, information about PD, dementia, other clinical risk factors for fracture and fracture events was obtained from review of complete inpatient and outpatient medical records spanning each subject's residence in the community. Compared to an equal number of age- and sex-matched non-PD referent subjects from the community, PD patients were at a 2.2-fold increased risk of fractures generally and a 3.2-fold greater risk of hip fractures specifically. Adjusting for age, the independent predictors of overall fracture risk in the PD subjects included female sex (hazard ratio [HR] 1.6; 95% confidence interval [CI], 1.1-2.3), dementia (HR, 1.6; 95% CI, 1.1-2.4) and chronic depression, which was associated with a reduced risk (HR, 0.4; 95% CI, 0.2-0.8). Hip fractures were predicted by dementia (HR, 2.2; 95% CI, 1.2-4.1). The increased fracture risk in patients with PD is not entirely explained by concomitant dementia, and additional study is needed to determine the relative contributions to fracture risk of falls versus bone loss in these patients.