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Hip Fractures Based on a Plenary Symposium “The Hip Fracture Epidemic” Chairs: Dennis Black, Bess Dawson-Hughes Speakers: Mary Bouxsein, Tamara Harris, Steven Cummings Saturday, October 16, 2010 ASBMR 2010 Toronto, Ontario. Incidence and Cause of Hip Fractures.
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Hip Fractures • Based on a Plenary Symposium • “The Hip Fracture Epidemic” • Chairs: Dennis Black, Bess Dawson-Hughes • Speakers: Mary Bouxsein, Tamara Harris, Steven Cummings • Saturday, October 16, 2010 • ASBMR 2010 • Toronto, Ontario
Incidence and Cause of Hip Fractures • Due to the aging population, hip fracture incidence is expected toincrease 2- to 3-fold by 2050. • Facts: • • 90% of hip fractures are due to a fall • • 50% of those who sustain a hip fracture do not have osteoporosis (OP) on BMD testing • • A fall to the side is 6x more likely to produce a hip fracture • • In a fall, the femur is 3.5x weaker than in a walking or standing configuration • • Bone loss sustained with age makes people even more vulnerable to a sideway fall • • 1 in 5 people die within the first year after a hip fracture • • 50% of people do not return to their independent living situation if they were independent prior to the hip fracture • • 50% of people will not walk independently if they were walking independently prior to the hip fracture • • Psychological outcomes following a hip fracture are poor
In the Western World • • Many countries in the West have seen a fall in the incidence of aged-standardized hip fracture rates in the last 10 or so years • • Rates in Denmark, Sweden and Norway have fallen by about 20% since about 1997 • • In the US, age-standardized hip fracture rates have fallen by about 25% in women and 20% in men since 1995
SOF (Study of Osteoporotic Fractures): Data on 80- to 84-year-olds • • Between 1992 and 2002, hip fracture risk decreased by approximately 23% • • Femoral neck BMD increased substantially in the same age group • • Between 1992 and 2002, weight gain, greater estrogen and bisphosphonate use, and significantly greater use of vitamin D and calcium may also explain hip fracture risk decline • OP therapies in the US: • • In women, they account for 9% at most of the ~25% decrease in hip fracture rates • • In men, they account for very little of the 19% decrease in hip fracture rates • • In the SOF, increasing use of OP treatments could account for ~25% of the decline in hip fracture rates
Hip Fractures in the East • In the early 1990s, age-specific hip fractures rates in Beijing, China, were about one-sixth or less than those in US Caucasians. • Approximately one decade later, age-specific hip fracture rates in women in Beijing have increased 3- to 4-fold, even though obesity rates are also rising. • Cultural Changes and Hip Fractures • • Use of cars over biking and walking has increased >4-fold since the early 1990s • • Citizens have moved from older residences where there were fewer chairs and no sofas to more Western-style apartments • • Squatting, which improves leg muscles and balance, was universal whereas now it is less common • • The incidence of hip fractures appears to rise with urbanization
Sarcopenia • Sarcopenia is the age-related loss of skeletal muscle mass • • In women, prevalence increases with age; in men, the prevalence increases to about the age of 50, after which it remains relatively stable • • Women with a history of hip fracture have a high prevalence of sarcopenia • • A reduction/increase in muscle weight = a corresponding loss/increase of bone • • One consequence of muscle loss is the risk of falling and subsequent fracture • OP and Sarcopenia • After adjustment for age and interval between fracture and DXA scan, a significant association between sarcopenia and OP was observed (P=0.026). • Adapted from Di Monaco et al. Arch Gerontol Geriatr 2010 Mar 4.Epub ahead of print.
Deconditioning and Aging • Deconditioning due to inactivity (bed rest) has a powerful effect on function and physical activity
Intentional and unintentional weight loss increase bone loss and hip fracture risk in older women
Exercise in the Elderly • Ten weeks of progressive resistance exercise training and nutritional supplementation in very frail elderly patients (age =87 years) led to: • • Increased walking speed • • Increased stair-climbing ability • • Increased spontaneous activity • • Decrease in depressive symptoms • Skeletal muscle mass is the strongest independent factor associated with femoral neck BMD in men and women
Future Perspectives • Myostatin and muscle loss: • • As a negative regulator of muscle growth, increasing levels of myostatin cause muscle loss • • Myostatin probably affects bone as well • • Future drugs that neutralize or eliminate myostatin may have appositive effects on muscle and bone