Osteoporosis

Epidemiology of Specific Chronic Diseases: Osteoporosis

Description
Osteoporosis is a skeletal disease characterized by low bone density and general deterioration of bone tissue. Bone fragility induces fractures that represent the major clinical aspect of the disease. There are three major fractures in osteoporosis; of the hip, vertebrae and distal radius.

WHO Definition
Bone density > 2.5 standard deviations below the young adult reference mean.

The probability of developing osteoporosis is dependent on:

  • The level of peak bone mass attained (usually in the 30s)
  • The rate of loss (a normal physiological process which stats around 40 years of age)

Symptoms

  • No symptoms during early stages of bone loss.
  • Back pain, loss of height over time.
  • Increased risk of fractures of the vertebrae, wrists, hips or other bones.

Complications
Hip fractures are a particularly serious consequence of osteoporosis requiring hospitalization, and are fatal in an estimated 20% of cases. Permanent disability occurs in up to 50% of cases.

Epidemiology

  • Osteoporosis and associated fractures are an important public health problem because of related morbidity, mortality and decreased quality of life.
  • According to the WHO the number of hip fractures worldwide due to osteoporosis is expected to rise three-fold from 1.7 million in 1990 to 6.3 million in 2050.
  • The WHO estimates that osteoporosis is responsible for an estimated 650,000 fractures a year in the European Union.
  • Osteoporotic fractures affect 1 in 2 women and 1 in 5 men over the age of 501.
  • Estimates for England and Wales suggest that each year osteoporosis results in 180,000 fractures in women alone (70,000 hip fractures, 41,000 wrist fractures and 25,000 vertebral fractures)1. However it is estimated that up to 70% of vertebral fractures fail to come to clinical attention.
  • Women have a higher rate of osteoporosis than men with a male to female ration of 4:1.
  • Fracture rates increase significantly with age and the lifetime risk of fracture among 50 year old women is estimated to be 40%. Higher rates of fractures among women are related to postmenopausal changes in bone metabolism.
  • An estimated 5% of the UK population has osteoporosis.

Risk Factors

  • Sex - females
  • Women who have had an early menopause or hysterectomy (before age 45)
  • Men who have low levels of testosterone
  • Increasing age
  • Low body weight
  • History of fracture
  • Smoking
  • High alcohol intake
  • Drug therapy - corticosteroids, heparin, cyclosporine, cytotoxic therapy
  • Physical inactivity
  • Impaired vision
  • Family history
  • Nutrition - low calcium and vitamin D intake.
  • People with Crohn's disease, coeliac disease or ulcerative colitis.
  • Type 1 diabetes, liver disease and kidney disease.

Prevention and Screening

  • A combination of vitamin D and calcium may reduce the rate of fracture by about 30% - in particular, for people aged > 60 and among those who show adherence to treatment.
  • Smoking cessation.
  • Avoid excessive alcohol.
  • Exercise.
  • Prevent falls

Drug treatments have been shown to reduce the risk of fractures by up to 50%1.
According to the National Osteoporosis Society, the total number of women prescribed medication for osteoporosis in the UK is approximately 48,000. However, one year after an osteoporotic fracture, the majority of patients are not prescribed any pharmaceutical agents for the prevention of further fractures1.

Measurements of bone mineral density are widely recognized as being effective at identifying patients who are a higher than average risk of fracture.

Appropriate drug therapy
Rehabilitation

References

  1. National Osteoporosis Society. Osteoporosis Facts and Figures.

© CM Kirwan 2006