WHILE a class of drugs called biphosphonates has been widely prescribed to inhibit bone breakdown, recent research suggests that their long-term use could raise the risk of rare but serious thigh fractures, prompting the Food and Drug Administration (FDA) to announce on Oct. 13, 2010 that biphosphonates will now carry a warning sign to this effect, says the December 2010 issue of the Weill Cornell Medical College’s Women’s Health / Advisor.

The National Osteoporosis Foundation estimates that about 10 million Americans have osteoporosis and 34 million are at risk for it.

Osteoporosis renders bone fragile which puts it at higher risk of fractures that can impede mobility and cause long-term functional impairment and disability.

An excellent way to boost bone health is through exercise and the best exercise is the weight-bearing kind...exercise that forces you to work against gravity, supporting your own body weight, says the health letter.

The January 2010 issue of the UC Berkeley Wellness Letter says that weight-bearing exercise (the kind recommended to help keep bones strong) is any sustained activity you do against the force of gravity, which is essential for maintaining bone mineral density.

The more load on the bone, the greater the benefit.

Thus, high impact activities or resistance workouts build more bone.

This is how activities stack up:

• Best for bones (weight-bearing/high-impact/resistance activities): running, jumping rope, aerobic dance, basketball, tennis, baseball, skiing, skating, stair climbing, hiking, weight lifting.

• Also good, but less so (weight-bearing/low-impact): walking, low-impact aerobics, most cardio machines (stair-climbers, rowers, elliptical trainers, treadmill walking)

• Least beneficial for bones (non-weight-bearing/non-impact): swimming, cycling, yoga, pilates.

Some researchers think that rowing, swimming and yoga, when done strenuously, are more beneficial than indicated here.

Short bouts/stronger bones:

To benefit your bones even more, divide up your exercise.

Short bouts (15 to 20 minutes of intense weight-bearing exercise), separated by at least eight hours, are more effective than one longer session.

Also, try to vary your weight-bearing activities, adds the letter.

Richard Bockman, M.D., Chief of the Endocrine Service at the Weill Cornell-affiliated Hospital for Special Surgery, says, “This kind of exercise places your bones under a certain degree of stress, stimulating the natural bone remodeling process.”

However, Dr. Bockman advises that if you have osteoporosis, consider getting advice from a registered physical therapist before you start your exercise regimen.

Protect your spine by avoiding exercises that flex, bend or twist it and avoid high-impact exercise to lower the risk of breaking a bone, adds the letter.

Like all your body tissues, your bones are metabolically active, changing as you grow, mature and age.

Dr. Bockman explains, “This change is enabled by a constant building up and breaking down of bone, a process called remodeling...where cells called osteoclasts break down (resorb) old bone and cells called osteoblasts form new bone.”

Up to about age 50, this system is balanced so that the ratio between new bone to old is maintained, but as we get older (and particularly after menopause in women) more bone is resorbed than is manufactured, Dr. Bockman adds.

Such an imbalance underlies osteoporosis...literally “porous bones,” a condition in which the microarchitecture of our bones is altered to an extent that they lose their density and become prone to fracture.

While a class of drugs called biphosphonates has been widely prescribed to inhibit bone breakdown, recent research suggests that their long-term use could raise the risk of rare but serious thigh bone fractures.

Thus, on Oct. 13, 2010, the FDA announced that biphosphonates will now carry a warning sign to this effect.

This FDA warning comes in the wake of a recommendation to do so by a task force of the American Society for Bone and Mineral Research (ASBMR), based on a report released on Sept. 14, 2010 which stated that of 310 cases of atypical fractures under study, 94 percent of the patients had been taking biphosphonates, most for more than five years.

Earlier concerns were raised about biphosphonates (Fosamax, Reclast, Actonel, Boniva) after several small studies reported that subtrochanteric (mid-thigh) and diaphyseal femur fractures (occurring in the long part of the thigh bone) were manifesting in patients who had taken biphosphonates for more than five years.

Biphosphonates boost bone density by interfering with the action of osteoclasts, ensuring that existing bone stays put.

“Initially this decrease in bone breakdown allows more calcium to be placed in the existing bone and bone density can improve,” explains Dr. Bockman.

However, this benefit eventually plateaus, raising concerns that the occurrence of these atypical fractures in some individuals may result from prolonged biphosphonate use which could be associated with altered bone properties that may weaken, not strengthen, bone, adds the doctor.

Although the ASBMR task force stressed that atypical fractures represent only about one percent of thigh fractures and that biphosphonates are an important weapon against fractures for the vast majority of patients; nevertheless, many doctors now recommend a five-year limit for taking biphosphonates, and the task force recommended that doctors annually assess whether patients still need to take them.

Dr. Bockman agrees that the drugs’ benefits outweigh their risks, emphasizing that patients shouldn’t stop taking them without discussing it with their doctor.

However, he notes that biphosphonates build up in the bone, so if you stop taking the medication after a period of time, its positive effects can persist but you may need to start taking the medication again, if your bone density declines.

Since the panel uncovered a general lack of patient awareness of atypical femur fracture, it offers these warning signs which include “groin or thigh pain for a period of weeks or months before the fractures.”

The task force likewise noted that more than one-third to one-half of the patients experienced these warning signs before their fracture, and more than a quarter of the patients who had an atypical thigh fracture in one leg had a similar fracture in the other leg.

Thus, if you are taking biphosphonates for osteoporosis, discuss with your doctor the task force recommendation of annually assessing whether you still need to take the medications, as well as the possibility of limiting biphosphonate use to five years, as many doctors now recommend, in order to avoid the risk of a rare but serious thigh bone fracture, that may arise from the long-term use of this medication.

Also, if you experience the warning signs of atypical femur fracture, seek your doctor’s advice and attention immediately.

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