If you're a woman over age 50 -- especially if you're white and slender -- and you haven't asked your doctor to test you for bone density, shame on you. Or shame on your doctor, if he or she hasn't insisted upon it.
About 10 million Americans -- 80 percent of them women -- suffer from osteoporosis (porous bone), and another 34 million are at risk, according to the National Osteoporosis Foundation. That's 55 percent of all Americans 50 or older. Approximately half of women and 25 percent of men over age 50 will have an osteoporosis-related fracture in their remaining lifetimes. According to one estimate, the incidence of hip fracture is expected to quadruple by 2050.
A woman's risk of having a hip fracture is equal to her combined risk of contracting breast, uterine and ovarian cancer, says the National Osteoporosis Foundation.
Osteoporosis causes bones to be so brittle that "even mild stresses like bending over, lifting a vacuum cleaner or coughing can cause a fracture," say Mayo Clinic experts on the Web site mayoclinic.com. In most cases, bones weaken when you have low levels of minerals, chiefly calcium, in your bones.
"Our bones do more than provide the structure for our bodies. They're the storehouse for minerals like calcium," said Dr. Vonda Wright, director of the Performance and Research Initiative for Masters Athletes at UPMC Sports Medicine.
Testing is important because in the early stages of osteoporosis, there is usually no pain or other symptoms. But if you've lost a fair amount of height over time and your posture has become more stooped, there's a high likelihood you have it.
Poor diet, a sedentary lifestyle and smoking increase the risk of osteoporosis, as does the early onset of menopause. White and Asian women are more at risk than black or Hispanic women. Slender, small-framed women are particularly at risk. Men with low levels of testosterone are at increased risk. For men, the risk of osteoporosis is greatest from age 75 upward.
Fighting osteoporosis should begin early. Nearly 90 percent of adult bone mass is acquired by age 18 in girls and age 20 in boys. Building strong bones in childhood and adolescence reduces the risk of osteoporosis later in life.
Although people acquire most of their bone mass early in life, their bones are constantly changing. New bone is made and old bone is broken down in a process called "remodeling." A full cycle of remodeling takes about two or three months, according to the Mayo Clinic.
Men and women reach peak bone mass in their mid-30s. After that, bone remodeling continues, but more mass is lost than gained. After menopause, when levels of estrogen drop, bone loss in women increases dramatically. Women can lose up to 20 percent of their bone mass in the five to seven years after menopause, the National Institute of Aging reports.
By the time they reach age 70, men and women lose bone at the same rate. But thanks to menopause, women have had a head start, and they have less bone to lose.
The risk of developing osteoporosis depends on how much bone mass is built up between the ages of 25 and 35, and how rapidly it is lost later. The more bone "in the bank," the more you can afford to lose without getting osteoporosis, the Mayo Clinic says.
The keys to osteoporosis prevention are diet and exercise. If you don't have enough calcium (essential for bone health) and vitamin D (essential for absorbing calcium) in your diet, bone loss will be accelerated. Bone growth is slowed by excessive amounts of alcohol and caffeine.
"Caffeine can cause a loss of calcium in the urine," said Dr. Murray Gordon, director of the Division of Endocrinology for Allegheny General Hospital. "Epidemiological studies indicate drinking more than five cups of coffee [a day] increases the risk."
Very high intake of protein and high intake of salt also can cause calcium to be excreted in the urine, Dr. Gordon said.
People ages 50 and older need a minimum of 1,000 milligrams of calcium per day, Dr. Wright said.
"For women in menopause, the figure is 1,200 milligrams." Dairy products and leafy green vegetables are the best natural sources of calcium, but most people over the age of 50 will require supplements.
Adults need 400 to 800 International Units of vitamin D per day to maintain bone health, Dr. Wright said. The best natural source of vitamin D is sunlight, but here in Pittsburgh, all but a handful of outdoorsmen and women don't get enough of it.
Dr. Gordon did a study of patients in Pittsburgh and discovered that 70 percent were deficient in vitamin D -- with 25 percent having a serious deficiency.
"As a country we are vitamin D deficient," he said. "One of the consequences of listening to the dermatologists [to stay out of the sun] is that we've exacerbated the problem."
The best food source for vitamin D is cod liver oil. Fish -- especially salmon, tuna, mackerel and sardines -- is another good source. Calcium supplements usually also contain vitamin D, and most milk is fortified with it.
Any kind of exercise is beneficial in retarding bone loss, but most beneficial are resistance training (weight lifting) and weight-bearing exercises, such as running and racquet sports.
Weight-bearing exercises and weight lifting are beneficial because they put stress on the body's bones.
"When our body perceives stress, it tells itself it is time to lay down more bone," Dr. Wright said. "The stress actually stimulates the body to store up more minerals."
Chinese researchers in a 2004 study found that practicing tai chi, a Chinese martial art form of slow, graceful moves, reduced significantly bone loss in post-menopausal women. The women in the study who did 45 minutes of tai chi a day, five days a week, lost bone at a rate 31/2 times slower than the women in the control group.
Tai chi also improves balance, which makes its practitioners less likely to fall as well as less likely to hurt themselves seriously if they do fall.
A study published in the Yoga Journal last year indicated women who practiced yoga five days a week actually increased their bone density.
If you've been diagnosed with osteoporosis or osteopenia, vigorous exercise may be a bad idea, because of the risk of fracture. But brisk walking is a good exercise for virtually everyone. So is dancing. Consult carefully with your physician before beginning or maintaining a workout program.
"Once you've been diagnosed with osteoporosis, it is not the time to stop being active," Dr. Wright said. "Your doctor may not want you to be out running but certainly walking."
A recent study of nurses indicate women who walked briskly for four hours or more a week had a 41 percent lower risk of hip fracture than women who walked an hour a week or less.
There is no cure for osteoporosis, but there are medications that can slow it down.
The primary prescription medications for osteoporosis are bisphosphonates. These inhibit bone breakdown, preserve bone mass and can even increase bone density in the spine and hip. But, Mayo Clinic experts warn, side effects can be severe. These include nausea, abdominal pain and an inflamed esophagus.
"Bisphosphonates are the first line [of treatment]," said Dr. Christine Gallis of West Penn OBGyn Associates. "But there are multiple options out there today."
"Bisphosphonates are proven to be effective at reducing fractures by 50 to 75 percent," Dr. Gordon said. "They've been around quite a while."
Fewer than 10 percent of her patients on bisphosphonates experience side effects, Dr. Gallis said.
"Most people will tolerate the generic Fosomax [alendronate] pretty well," she said. "With the economy what it is, that is what I would try first with most of my patients."
A study published in the Journal of the American Medical Association in February concluded: "Bisphosphonates have been shown to be safe and are not associated with long-term impairment of [kidney] function." Research indicates bisphosphonates are especially beneficial for men, young adults and people with steroid-induced osteoporosis.
For patients who have or are at risk for side effects from bisphosphonates, two hormonal-based drugs, Avista and Forteo, offer promise, Dr. Gallis said.
"[Avista] works totally different from bisphosphonates," she said. "It also helps to correct breast cancer."
While bisphosphonates slow bone loss, Forteo, a relatively new drug, actually stimulates production of new bone, Dr. Gallis said.
Bisphosphonates have been associated with osteonecrosis of the jaw, an area of the bone that has lost its blood supply. The overlying tooth often falls out, and a non-healing lesion remains.
But this condition is associated chiefly with patients who are taking large amounts of bisphosphonates intravenously, Dr. Gordon said.
"The risk of oral bisphosphonates for necrosis of the jaw is extremely low, less than one case in 100,000," he said. Patients who are at a high risk for fractures shouldn't be dissuaded from taking bisphosphonates by those odds.
A DXA (dual-energy X-ray absorbtiometry) test can determine whether or not you have osteoporosis or its predecessor condition, osteopenia. The DXA test measures bone density. It takes from 10 to 30 minutes to perform, depending on the part of the body being X-rayed, typically the hips, lower spine or wrist.
Jack Kelly can be reached at firstname.lastname@example.org or 412-263-1476.