Osteopenia, increased fracture risk and improvement in bone density with the use of Bisphosphonates in patients with Pompe disease

Abstract

age. The causes for age related bone loss are multifactorial and the risk factors most likely have amuch earlier onset during bone development. The peak bone mass, reached between the ages of 25–30 is crucial for the future fracture risk. A small number of young patients develop early bone loss or an inability to fully build the skeleton. The goal of our investigation was to characterize juvenile osteoporosis and find histomorphological differences between juvenile osteoporosis and senile osteoporosis. Methods: Iliac crest biopsies, embedded into MMA, from patients younger than 30 years of age with clinical manifestation of osteopenia were analyzed. 344 male and 284 female patients were compared with data from a total of 21000 biopsies from osteoporotic patients of all ages. We evaluated medication, primary diseases, histological bone turnover and osteoid surfaces, as well as hematopoietic disorders. Results: 3% of all 21000 patients in the register were younger than 30 years of age. The portion of male patients was slightly higher (1.6% vs.1.4%). Histological bone turnover showed 40% of the patients had low turnover osteoporosis (LTO), 14% of the patients high turnover osteoporosis (HTO), and 46% had a normal and balanced turnover. 8.8% had an additional osteomalacic component. 6.7% had reactive bone marrow changes. 8.5% had corticosteroid induced bone loss. Rare primary causes for juvenile osteoporosis were as follows: M. Cushing, systemic mastocytosis, osteogenesis imperfecta, (pseudo-) hypoparathyroidism, dysplastic osteopathy, hypogonadism, primary hyperparathyroidism, gout-oxalate-osteopathy, Bamatter-syndrome and hyperthyrosis. 11 female patients received bisphosphonate therapy. Discussion: Patients with juvenile osteoporosis are rare and account for 3% of all cases we investigated. Less than 20% have an underlying disease or known risk factor that can be linked to osteopenia and referred to as secondary osteoporosis. Over 80% of children and young adults with bone loss have to be considered as idiopathic based on the histological diagnosis. Surprisingly, the number of LTO outweighs HTO conditions by 36% leading to the assumption that a low remodeling rate with little bone formation accounts for a negative balance in the bone mineral units during growth. Osteomalacic components are not more frequent than in the older population. Reactive bone marrow changes, e.g. due to anorexia nervosa, is 2–3% higher than in the total population, indicating a possible nutritive cause for osteopenia in more patients. Malignant hematological disorders were not present. Only 1.8% received a bone specific treatment.