ABSTRACTS: Oral Presentation Abstracts
Introduction: We are decribing the results of the pilot study we conducted on 33 cystic fibrosis (CF) patients (aged 4.5–43.7 years, 15 of them female, 79% <18 years), which is part of a larger study. As the survival time of CF patients increases, new problems, such as osteoporosis, have to be considered. Constant inflammation, malabsorption, hypogonadism and systemic corticosteroid treatment lead to reduced body composition and influence bone metabolism. Osteoporosis has severe sequelae for life quality and health status. While some studies found osteoporosis in CF patients already in childhood and a fast decline of bone density in adulthood, others report normal bone density in CF patients.
Methods: Using pQCT (Peripheral Quantitative Computer Tomography), we measured bone mineral density and cross section areas of bone components and muscle of the nondominant forearm. Using DEXA (Dual-Energy X-ray Absorptiometry), we measured whole body bone mineral density (in 23 patients). We used also laboratory, spirometry and anthropometry in CF patients seen regularly.
Results: Weight, height and BMI of our patients were statistically significantly lower than in normal population. Bone mineral density (BMD, measured by DEXA) and trabecular bone density (TBD, measured by pQCT at the distal radius) were not lower than in normal population(the mean Z-score for BMD was −0.084±1.097, p=0.393, the mean SDS for TBD was 0.214±0.873, p=0.809). There was no dependence of BMD or TBD on serum calcium, phosphate, alkaline phosphatase, immunoglobulin G and on FEV1 (one second forced expiratory volume). Cross section area of proximal forearm muscles was smaller than both height-matched and age-matched references. Cortical bone area was smaller according to age, but appropriate for muscle area. BMD and TBD were not strongly correlated to weight-for-height in younger patients (R=0.369 and 0.213, respectively), correlation to BMI in older patients was stronger (R=0.782 and 0.563, respectively). In our CF patient population, osteoporosis was found by DEXA in 1 patient only and osteopenia in 3, but, excepting 1 patient, the bone mineral density was in normal range according to their low weight. No patient met criteria for osteoporosis in pQCT measurements. This low percentage was not due to a particularly favourable nutritional state.
Conclusion: These data indicate, that a good specialized medical care for CF patients could prevent osteoporosis. An interesting finding was the thinner cortical bone in CF patients, which may be due to their lower muscle mass. When assessing bone density in pediatric patients, height, weight and muscle mass has to be considered, not just age.