All you need to know about osteoporosis

Osteoporosis (OP) is a generalized metabolic disease of the skeleton in which bone mass is lost, bone quality deteriorates, resulting in a loss of bone strength and elasticity, leading to increased fragility. In case of OP the risk of bone fracture is increased even with a minimal amount of force.

Bone fractures jcan significantly reduce quality of life. They become ever more common in older age, creating a major public health problem and socio-economic burden on society. In postmenopausal women, initially bone loss of the vertebrae predominates, with fractures of the long bones increasing in the elderly. Typical sites of pathological fractures are vertebrae at the transition of the back and lower back, the wrist, the upper arm near the shoulder and the hip.

Primary osteoporosis, postmenopausal and senile, is the most common, but there are ever more cases of secondary OP caused by diseases of other organs or drugs (e.g. steroids, heparin, aromatase inhibitors for breast cancer...).

OP is a widespread disease, in Hungary affecting about 600 000 women and 300 000 men over the age of 50. This means that 1 in 2 women and 1 in 5 men over 50 suffer from osteoporosis. The clinical significance of OP results from pathological fractures and their complications. Hip fractures are of greatest importance - not only do they impair quality of life, but they can also pose an immediate risk of death. The majority of vertebral fractures develop gradually, remain hidden for a long time, and are detected immediately in only one tenth of cases - in the long term, they alter the posture of the spine, thus increasing the wear and tear of the lower segments of the spine.

The treatment of osteoporosis is therefore essentially aimed at preventing fractures.

Osteoporosis and the development of osteoporotic fractures are determined by several risk factors. Patients requiring therapy are selected on the basis of risk factors and bone mineral density.

The most significant risk factors for fractures are age and reduced bone mineral density (BMD). Other risk factors include female gender, low body weight (BMI, body mass index), long-term immobilization, a history of previous OP fracture or hip fracture in the patients’ parental history, increased bone loss, steroid therapy, smoking, alcoholism, rheumatoid arthritis and other underlying conditions leading to secondary osteoporosis.

Based on validated risk factors, the WHO has developed a fracture risk assessment system that integrates the patient's risk factors and provides a 10-year probability of an OP fracture. This is the FRAX index (fracture risk assessment tool), a computerized method for estimating fracture risk. FRAX calculates country-specific risk based on the femoral neck BMD, body mass index BMI, age, gender and the presence of additional risk factors detailed above. The computer algorithm can be accessed and calculated by anyone on the internet. https://www.fraxplus.org/  FRAX uses national data for Hungarian patients. When FRAX is 20% for the general fracture risk, or 3% for hip fracture risk, this is considered pathological.

The diagnosis of osteoporosis is based on bone mineral density (BMD). Measured BMD (g/cm2) is compared to the mean value of peak bone mass in healthy young people and the difference (T-score) is expressed as the standard deviation (SD) of the normal value for the young population. Based on the T-score categories are established:

• healthy bone: T-score > -1.0                               

• osteopenia: T-score > -1.0 and < -2.5 SD    

• osteoporosis: T-score < -2.5                              

• severe osteoporosis: T-score < -2.5 + at least 1 osteoporotic bone fracture. 

The most common method of measuring BMD is dual energy X-ray imaging (DEXA). The recommended measurement sites are the lumbar spine (LI-IV) and the hip region (femoral neck).

Laboratory tests (serum calcium, phosphorus, parathyroid hormone, vitamin D, TSH) are necessary to define the pathogenetic process of reduced BMD, while the determination of markers of bone metabolism (biomarkers of bone breakdown and formation, in particular collagen cross-linking peptide and osteocalcin) helps in the choice of therapy.

The management of OP and the prevention of pathological bone fractures are based on adequate calcium (Ca) and vitamin D intake. Drug therapy, such as bisphosphonates, denosumab or even teriparatide, may be needed to treat osteoporosis and to reduce the increased risk of fractures in postmenopausal women and men over 55 years of age.

Physical activity is always important! Physical activity stimulates bone cells and by increasing muscle strength, the possibility of falls is reduced. Regular physical exercise is recommended for prevention and in cases of osteopenia. In practice, this means exercises such as high impact aerobics, trampoline, brisk walking, etc. at least three times a week, at the appropriate intensity. Avoiding immobility and reducing the risk of falls are also important preventive factors. Adequate modification of living environment (e.g. removing obstacles, wearing glasses, reducing sleeping pills) significantly lowers the fracture risk. Nevertheless, prevention starts in the teens. Regular movement, sports and resistance excercises at an early age promote the development of more bone mass, thus providing a higher peak mass as the basis  for bone loss in later life.