From Spain: Cystic fibrosis patient bone density and physical activity

http://www.ncbi.nlm.nih.gov/pubmed/21292759

Chest. 2011 Feb 3. [Epub ahead of print]
"Bone health, daily physical activity and exercise tolerance in cystic fibrosis patients"
Tejero García S, Giráldez-Sánchez MA, Cejudo Ramos P, Quintana Gallego E, Fernández FJ, García Jiménez R, Cano Luis P, Gómez de Terreros I.

Medical Doctor in Sport Medicine. Trauma and Orthopaedic Surgery of the "Virgen del Rocío" Hospital. Sevilla. Spain.
Abstract
ABSTRACT

BACKGROUND: Daily physical activity (PA) may be an excellent tool for the maintenance of bone health in patients with cystic fibrosis (CF). The aim of this study was to analyze the possible association between physical capacity and activity, and bone mineral density (BMD), in young adults with CF. A secondary goal was to evaluate vertebral fractures in this population.

METHODS: A cross-sectional study was conducted in 50 CF patients, who were clinically stable and older than 16 years old but not being lung transplant recipient. PA was quantified using a portable motion monitor (BodyMedia Fit Armband). Cardiopulmonary exercise test (CPET), and 6-minute walk test (6MWT) assessed exercise capacity. BMD was obtained from dual energy X-ray absorptiometry (DXA) of the lumbar column, hip and whole body. To analyze vertebral fractures and deformity, we performed the Genant and Cobb methods.

RESULTS: Daily PA time at low (3-4.8 METs) and moderate (4.8-7.2 METs) intensity was correlated with Z-Score BMD of the lumbar column (r=0.36, p<0.01 and r=0.59, p<0.001, respectively), the neck of femur (r=0.51, p<0.001 and r=0.72, p<0.001), and the total hip (r=0.54, p<0.001 and r=0.74, p<0.001). PA, BMI, age and sex were found to be predictors of BMD. Vertebral fractures correlated with kyphosis (r=0.42, p=0.02), but not with BMD. Mild and severely affected patients differed in vertebral fracture rate and kyphosis prevalence (p=0.002 and p=0.013, respectively).

CONCLUSIONS: The most active patients with better exercise capacity had higher BMD. Those with more affected pulmonary function had greater prevalence of vertebral fractures and dorsal kyphosis.