Parathyroid Hormone Levels are Related to Body Composition in Parkinson's Disease Patients.

SEIJO M, PARISI MS, MASTAGLIA SR, FERNÁNDEZ MC, DÍAZ SP, DEFERRARI JM, BAGUR A, MICHELI F, OLIVERI B

Philadelphia, Pennsylvania, USA

Congreso; Twenty-Eighth Annual Meeting of the American Society for Bone and Mineral Research; 2006

The American Society for Bone and Mineral Research

Recently, parathyroid hormone (PTH) has been positively correlated to body weight and fat mass in primary hyperparathyroidism and healthy postmenopausal women.Patients with Parkinson´s disease (PD) are known to have a greater risk of falls and fractures than healthy subjects. In turn, PD patients have been found to have low body mass index (BMI), diminished fat mass and low levels of 25OHD, all factors related to occurrence of fractures.In this context, we evaluate the relationship between PTH levels and body composition parameters, measured by DXA, in 22 PD patients (12 women, 10 men) with a mean age of (X+/-SD) 67.3±6.8 years. Biochemical determination of mineral metabolism included: serum calcium, phosphorus, 25OHD, PTH, total alkaline phosphatase (AP), and urinary calcium.PD patients presented lower BMI and fat mass compared to sex and age-matched controls (24.5+/-3.9 vs 25.9+/-2.3kg/m2, p<0.05; and 18.28+/-7.71 vs 21.83+/-5.49kg, p<0.05; respectively). One patient presented hypocalciuria, and 3 patients had slightly increased levels of PTH. Levels of 25OHD were below the hypothetically desirable 30ng/ml in 18 patients (81%).PTH levels correlated negatively to bone mineral content (r:-0.479, p<0.05), lean mass (r:-0.537, p<0.02), fat mass (r:-0.537, p<0.02) and height (r:-0.578, p<0.01). 25OHD levels positively correlated to bone mineral content (r: 0.432, p<0.05), and height (r:0.433, p<0.05), and negatively to AP levels (r:-0.435, p<0.05). Surprisingly, no correlation was found between PTH and 25OHD levels. BMI positively correlated to all body composition parameters, except lean mass.Our observations suggest an evident relation between body composition parameters and PTH levels in PD patient. However, correlations related to fat mass and PTH, found in PD patients, are opposite to those reported in healthy postmenopausal women and patients with primary hyperparathyroidism. We can postulate that insufficient 25OHD levels could be related. However, it remains to be elucidated whether PTH levels are a determinant of body composition or vice versa and how these alterations are related to an increased risk of falls and fractures in PD patients.