Risk factors for hip fracture among elderly patients with Parkinson's disease.

Incidence of hip fracture among patients with Parkinson's disease (PD) is high, especially in elderly women. To determine effects of various factors on hip fracture risk, we prospectively studied fractures in a cohort of 115 elderly patients of both genders with PD (46 men, 69 women; mean age, 71.9 years) for 1 year. At baseline, we recorded body mass index (BMI), Hoehn and Yahr stage, and postmenopausal interval, and also measured bone mineral density (BMD) and serum concentrations of ionized calcium, intact parathyroid hormone (PTH), pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP; a bone resorption marker), and 25-hydroxyvitamin (25-OHD). During the year hip fractures occurred in 18 patients (2 male and 16 female). We compared baseline variables between patients with and without hip fracture. PD patients with decreased BMI, lower BMD, and low concentrations of serum ionized calcium, and 25-OHD (mean 4.0 ng/ml) with compensatory hyperparathyroidsim had increased risk of hip fracture. Female PD patients with long postmenopausal intervals also had increased hip fracture risk. BMI, illness duration, postmenopausal intervals, Hoehn and Yahr stage, 25-OHD, PTH, calcium, and ICTP were determinants of BMD in patients with fracture. Elderly PD patients with low BMI, low BMD, and serum 25-OHD concentrations < or =5 ng/ml with secondary hyperparathyroidism have increased risk of hip fracture, as do female PD patients with long postmenopausal intervals.