Osteoporosis - The New Generation
by: Dan Fogel
An estimated 10 million Americans have bones that are porous enough that they could be classified as having osteoporosis. Another 18 million aren't quite there yet, but have bones that are weak enough that they have an increased risk of fracture.
Often thought to be solely restricted to women who are 70 years old or more, osteoporosis is claiming new victims. Men now account for 20% of the hip fractures and we now know that women can lose 25% or more of their bone mass in the first 5-7 years after menopause.
Women still have the biggest risk because they generally start with less bone than men to begin with, but men are more than twice as likely to die in the year after a hip fracture than women are.
Medical experts are also starting to lean towards watching women for osteoporosis in the few years before menopause, often known as pre-menopause. Hormone balances are starting to change and so can the balance between building and tearing down bone.
Osteoclasts are constantly digging holes in bones while osteoblasts keep filling them in. As we age, the balance between osteoclasts and osteoblasts change and we start losing bone faster than we are building it. So far, medications that are prescribed for osteoporosis only slow down the osteoclasts from breaking down bone and hopefully that will allow a net gain in bone density.Women at Risk
"Osteoporosis is a silent risk factor for fracture, just as hypertension is for stroke," says Robert Lindsay, former president of the National Osteoporosis Foundation. "High-risk women should be tested to detect low bone density before fractures occur."
Who's at high risk? Any Caucasian woman aged 65 or older, according to the foundation's guidelines.' (It had too little data to estimate the risk of fractures in men or non-white women.) But, like recovering hip-fracture patient Pat Wootan, some younger women may also be at risk.
"People who have fractured any bone after the age of 50 are at higher risk for another fracture," explains Bess Dawson-Hughes of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston.
That's not true if your bone is broken in a car accident or by some other massive force, she explains. "But if you simply fall and break your wrist at the age of 50, you may be a candidate for drugs that treat osteoporosis, because that kind of break may be a sign that your bones are weak."
You're also at risk if you smoke cigarettes or if your mother, father, or sibling had a fracture that wasn't caused by massive force. And weighing less than 127 pounds means a higher risk, at least in women over 50. "Thinner people have smaller bones and less padding when they hit," explains Dawson-Hughes.
That's not an excuse to gain -- or to avoid losing weight if you need to. It's not worth getting diabetes, high blood pressure, or other health problems just to help prevent a bone fracture. But a low body weight should nudge women aged 50 or older to get a bone density test. The questions is: which kind?
"Each method predicts the risk of fractures, but I recommend DEXA," says Deborah Sellmeyer of the University of California at San Francisco.
DEXA, or DXA, stands for dual-energy X-ray absorptiometry. Unlike other tests, it can measure density in the spine, hip, and wrist, the three major sites for fracture. A DEXA scan exposes patients to only about one-hundredth of the radiation they'd get from a chest X-ray,
What's more, when the World Health Organization (WHO) defined osteoporosis, it relied on studies that used DEXA. "It's more difficult to apply the WHO guidelines with another type of bone density test," says Sellmeyer.
What To Do
"When cholesterol tests first came out, it wasn't clear what was the 'normal' range and at what number you should begin treatment," says Lindsay. "The same was true for bone density tests."
That picture has changed in recent years. Now researchers know what a bone density score means, and they have more options for drug treatment.
Estrogen is no longer the only option. Drugs like Fosamax usually work. And, unlike with estrogen, you don't have to worry that they may raise the risk of breast cancer. "We can tailor treatment to a woman's concerns and her risk of other problems," says Sellmeyer.
Whether or not you're at high risk, you can take steps to protect your bones at any age. Here's what experts recommend:
1) Shrink your calcium deficit. The average American consumes only 600 milligrams of calcium a day. Yet the National Academy of Sciences recommends 1,000 mg for adults under age 50 and 1,200 mg for those over 50.
"Adequate calcium intake will slow the rate of bone loss and reduce the risk of fractures in most bones in older adults," says Johnston. It doesn't matter if you get your calcium from food, a supplement, or a growing number of cereals, juices, and other foods that are fortified.
"Randomized controlled trials have shown that calcium and vitamin D can reduce the risk of fractures in older people by up to 40 percent," says Sellmeyer.
But men should be especially careful not to exceed the recommended levels. Too much calcium (more than 2,000 mg a day) was linked to a higher risk of prostate cancer in some studies. It's too early to know whether other studies will confirm those results, but why take a chance?
A bonus: In a study on bone density and fractures, Dawson-Hughes and colleague Elizabeth Krall found that older people who took calcium and vitamin D supplements were also less likely to lose teeth than those who took a placebo. "It's the first randomized controlled trial to show that calcium and vitamin D made a difference for tooth loss," says Dawson-Hughes.
And it's not just adults who need calcium. "It's especially important that adolescents get enough calcium to reach their genetic peak for bone mass," notes Johnston.
If that's not compelling to teenagers, other recent findings might be: Among teenage girls who participate in sports, two preliminary studies indicate that heavy soda-drinkers are more likely to break a bone than those who drink fewer soft drinks.
2) Get enough vitamin D. Without sufficient vitamin D, your body can't absorb calcium efficiently. When Dawson-Hughes and her Tufts colleagues gave daily vitamin D and calcium supplements to postmenopausal Boston women from October through April, the women lost less bone than women who took just calcium.
"And when other researchers gave vitamin D supplements or a placebo to elderly people whose blood vitamin D levels were in the lower half of the normal range, the vitamin-D-takers had half as many falls over the next year as those who got the placebo," says Dawson-Hughes. Those results suggest that the National Academy of Sciences may have aimed too low when it set its vitamin D recommendation at International Units (IU) a day for people over 70.
"There's a growing consensus that people need blood vitamin D levels in the upper half of the so-called normal range," says Dawson-Hughes. "But only two-thirds of older women who get the recommended intakes reach the upper half," probably because some women don't absorb vitamin D well or spend less time in the sun than others.
"With the current advice, we're leaving a number of women behind," she adds. To play it safe, Dawson-Hughes advises women older than 70 to get 800 IU a day of vitamin D.
3) Get sufficient protein. The link between protein and bone is still fuzzy. Some scientists claim that protein harms bone because it forces the kidneys to excrete more calcium. But that's only part of the story, say others.
"The question is whether the body adjusts over the long term," says the University of California's Deborah Sellmeyer. "And no one knows the answer."
In some studies, people aged 65 or older who eat more protein are less likely to break a hip.
"Contrary to common misconceptions, the more protein older women eat, the less their bone loss and the better their bone density," says Dawson-Hughes.
One possibility: "Protein increases calcium in the urine, but it also promotes a bone growth factor, and it's the balance between losses and gains that determines bone density," she suggests.
It's also possible that older people who eat less protein have weaker bones because they eat poorer diets. And it's conceivable that the findings in older people may not apply to others. But all things considered, the evidence so far suggests that protein protects, rather than harms, bones as they age.
"Cutting back on protein is exactly the wrong thing to do,"says Harvard Medical School's Marian T. Hannan. "That's especially true for older folks, who are facing all kinds of insults to their health. They may need the protein to recover from infections, surgery, or chronic disease."
That's not to say that you should eat more red meat. To reduce the risk of heart disease and cancer, it makes more sense to get your animal protein from chicken, fish, and low-fat milk, yogurt, or cheese.
Says Hannan: "Whether you're nine or 90, it makes sense to eat a well-balanced diet that includes calcium, protein, and plenty of fruits and vegetables."
It's also clear that protein supplements can help elderly women recover from a hip fracture. But others needn't reach for a can of Ensure.
"Women need at least the Recommended Dietary Allowance for protein to reduce their risk of fracture," says Dawson-Hughes. That's 0.4 grams for every pound you weigh, which translates into 50 grams of protein for a 120-pound woman or 60 grams for a 150-pound woman. "We don't have enough evidence to say that they should get more," she adds.
4) Get enough vitamin K. Vitamin K helps blood coagulate. But in recent years, researchers have found that women who consume the least vitamin K have a higher risk of hip fractures than women who consume more.
"In the Framingham Osteoporosis Study, we found that the higher the intake, the higher the bone density," says Sarah Booth of the Jean Mayer U. S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston.
Researchers aren't certain how much vitamin K is enough, but in Framingham, those at highest risk got an average of 60 micrograms a day and those at lowest risk averaged 250 micrograms a day.9 "It would be a major accomplishment if we could get all Americans to the current recommended levels - 90 micrograms a day for women and 120 micrograms for men," says Booth.
No one will know for sure if vitamin K can prevent fractures until scientists complete several trials that will test the vitamin against a placebo. In the meantime, it makes sense to get enough K. Dark green lettuce, spinach, collards, and other greens are some of the best sources.
Some multivitamins have K, but many leave it out. You might have better luck with a calcium supplement. Each Viactiv Soft Calcium Chew, for example, supplies not only 500 milligrams of calcium, but 40 micrograms (half a day's worth) of vitamin K.
Caution: if you take coumadin or other blood-thinners, check with your doctor before taking any vitamin K, because it might change the dose of drug you need to prevent blood clots.
5) Avoid excess caffeine. Caffeine increases calcium losses in the urine, but only some studies have found a higher risk of fractures in people who consume large amounts (at least three cups of coffee a day). The latest studies may explain the discrepancy. Researchers found that caffeine increased bone loss only in women over 65 who have one variation of a gene involved in making vitamin D."Until we can know an individual's genotype, we have to assume that each person has a genetic susceptibility to osteoporosis," says Linda Massey of Washington State University in Spokane. "It's prudent to recommend that anyone over 65 get adequate calcium and no more than 300 milligrams of caffeine a day." That works out to two cups of brewed coffee, four cups of brewed tea, or six cans of cola or other caffeinated soft drinks.
6) Exercise to strengthen muscles and bones. "If you measure the playing arm of a pro tennis player, it has more bone than the non-playing arm," explains Indiana University's C. Conrad Johnston.
"When you exercise, the muscles pull on the bone and produce strain and a slight bending. If you increase the strain, it increases bone."
Exercise has the greatest impact when bones are still growing, but it also works in older people. "And even if we don't have a lot of 75-year-old women pumping iron, they can still walk or do other exercise that builds their muscles," says Johnston. "And muscle strength can keep people from falling."
Any exercise that's weightbearing-that is, done standing up - builds bone. That includes walking, jogging, stair climbing, dancing, and tennis. The exceptions: "Swimming is not weight-bearing, and cycling is only partially weight-bearing," says Dawson-Hughes.
7) Forestall falls. Studies have homed in on several factors that make an older person more likely to fall. For example, "beta-blockers, which lower blood pressure, can cause lightheadedness when a person stands up," explains Dawson-Hughes. Sometimes doses can be adjusted to minimize the problem.
Not surprisingly, poor vision can make someone trip and fall. "Older people may have a cataract or other visual impairment that remains a problem even after they try to correct it," says Sellmeyer.
To lower your risk, "you can fall-proof the environment," says Dawson-Hughes. "Get rid of scatter rugs, remove clutter, and make sure you have good lighting on steps."