Prevalence

Some information on the epidemiology of osteoporosis is presented below:

• approximately 3 million people are thought to suffer from osteoporosis in UK (1)
  • older white women are affected more commonly
  • there is a significant increase in the prevalence of osteoporosis after menopause with 2% of the women affected at 50 years which increases to more than 25% at 80 years (2)

Fragility fracture is the clinically apparent and relevant clinical sequelae of osteoporosis (2).

• osteoporosis causes 180,000 fractures annually,
  • of these, 70,000 are hip fractures, 25,000 are clinical vertebral fractures, 41,000 are wrist fractures (2)
  • one in two women and one in five men over the age of 50 are likely to break a bone due to poor bone health (1)
    • the lifetime risk of fracture for a 50 year old Caucasian woman is about 3X that for a man of the same age
• postmenopausal women with an initial fracture are at substantially greater risk of subsequent fractures e.g - a woman with a vertebral fracture has an increased relative risk (RR) of 4.4 for a further vertebral fracture, 2.3 for a hip fracture, and 1.4 for a wrist fracture (3)
• hip fractures
  • in women aged over 50 years, the lifetime risk of hip fracture is estimated to be one in five (3)
  • in men, the rate of hip fracture does not usually show marked increase until the eighth decade
  • each year more than 35 000 postmenopausal women will experience a femoral neck fracture; 17% will die due to this
  • the incidence of femoral neck fracture increases after the age of 65 years, more markedly in women than in men, and in Caucasians than Blacks
    • there is evidence that the rate of bone turnover is lower in blacks than in whites (3) - bone resorption and bone formation are closely coupled in the steady state. If reconstitution of previously resorbed cavities at remodeling sites is incomplete in osteoporosis, it has been suggested that a reduction in the rate of skeletal remodeling could provide a means for maintaining and preserving bone mass in blacks (3)
    • a South African study (4) suggests that the higher peak femoral neck bone mineral density (BMD) in South African blacks than in whites might be determined by greater weight-bearing in blacks and that the significantly lower femoral neck BMD in postmenopausal whites than in blacks is determined by lower peak femoral neck BMD and a faster postmenopausal decline in BMD in whites. The higher incidence of femoral neck fractures in South African whites than in blacks is probably determined by the lower femoral neck BMD and longer femoral neck axis length in whites (4)
• vertebral fractures
  • the incidence of vertebral fractures in women increases markedly from the age of 50 years with the lifetime risk is estimated to be one in three

Reference:

• (1) NHS choices. Osteoporosis
• (2) NICE (October 2008). Alendronate, etidronate, risedronate, raloxifene and strontium ranelate for the primary prevention of osteoporotic fragility fractures in postmenopausal women
• (3) Weinstein RS, Bell NH. Diminished rates of bone formation in normal black adults. N Engl J Med. 1988 Dec 29;319(26):1698-701.
• (4) Daniels ED et al. Differences in mineral homeostasis, volumetric bone mass and femoral neck axis length in black and white South African women. Osteoporos Int. 1997;7(2):105-12.