By Rebecca Terry, M.D.
The most common bone disease is also among the most preventable.
A silent disease, osteoporosis can progress undetected for years until a fracture happens. Fractures occur when an imbalance in bone remodeling causes bone resorption to occur at a faster rate than bone formation creating a loss in bone mass and structure and causing bone to weaken and the risk of fracture to increase.
In the U.S., a postmenopausal woman’s risk for hip fracture exceeds her risk of breast, endometrial and ovarian cancer combined. American women have a 50 percent chance of developing an osteoporotic fracture sometime during their lives.
The most common sites for fracture are the spine, hip and wrist. These fractures may heal without incidence, but many result in chronic pain, disability and death. Twenty percent of hip fracture patients will require long-term nursing home care, and only 40 percent will fully regain their pre-fracture quality of life.
Vertebral (spine) fractures can cause chronic back pain, height loss and permanent changes in the spine alignment. This change, called kyphosis, limits physical activity, impairs the ability of the lungs to fully expand, alters digestion and bowel function and has been associated with depression and lowered self esteem. In the U.S., the estimated annual cost of caring for patients with these fractures was estimated at $17 billion in 2005. With the aging population, the number of hip fractures and the associated cost could double or triple by 2040.
The majority of osteoporotic fractures can be prevented. The National Osteoporosis Foundation (NOF) recommends several interventions for reducing low bone mass and fracture risk:
- An adequate intake of calcium and vitamin D
- Lifelong participation in regular weight-bearing and muscle-strengthening exercise
- Avoidance of tobacco
- Identification and treatment of alcoholism
- Treatment of physical and health factors that increase the risk of fracture
Daily calcium intake and vitamin D have been shown to reduce fracture risk and increase bone density. Recommended daily consumption is at least 1,500 mg of calcium from childhood to age 30 while our skeleton is actively laying down its peak bone mass. Once peak bone production ends, the recommendation drops to 1,000 to 1,200 mg. The average American gets only 600 mg of calcium in their diet. This, coupled with losing estrogen’s protection of bone reservoir in the first three years following menopause, causes skeletal calcium to deplete at an accelerated rate. So, women over age 50 need 1,500 mg daily.
Calcium-rich foods are the ideal first-line approach, but supplements can also be used. About 75 to 80 percent of the calcium consumed in American diets is from dairy products. One cup of milk and 6 oz. of yogurt each provide 300 mg. Before age 30 and after menopause we need five servings daily. Calcium-fortified orange juice is another good source.
Vitamin D and calcium go hand in hand. The body needs vitamin D to absorb calcium. It is also essential for muscle performance, balance, mood and possibly cancer prevention. The NOF recommends 800 to 1,000 IU of vitamin D daily for adults over age 50. Good dietary sources are vitamin-D-fortified milk and cereals, egg yolks, saltwater fish and liver. Soy milk does not contain vitamin D. Sunlight is another source. Twenty minutes of sun exposure on the arms and legs two to three times a week increases the body’s Vitamin D levels. Many calcium supplements also include 400 IU of vitamin D. The safe upper limit for vitamin D was set at 2,000 IU daily in 1997. More recent evidence indicates that higher amounts may be needed as we age due to lowered absorption of the vitamin from our GI tract.
Regular weight-bearing exercise increases bone mass while lowering the risk for fracture by preventing falls. It improves agility, posture and balance. Thirty minutes daily is the minimum. Walking, jogging, Tai’Chi, stair climbing, jumping on a trampoline, dancing and tennis are good examples of weight-bearing exercise. Muscle-strengthening weight training helps build bone over time. If you have osteoporosis, avoid sit ups and exercises that require forward flexion of the spine; these can increase the risk of spinal fractures. Physical therapists are good resources for initiating muscle-strengthening and resistive exercise programs.
Tobacco products promote skeletal bone loss. A smoking cessation program is essential for osteoporosis prevention and treatment. Excessive alcohol intake of more than three drinks daily is another culprit.
Prevention of falls is key. Risk factors include a personal history of falling, muscle weakness, gait problems, poor balance and poor vision. Remove throw rugs and install assistive devices, such as hand rails, in bathrooms to help prevent falls. Evaluate medications for possible oversedation. Exercise to improve balance and muscle tone. These recommendations can be supplemented by hip protector devices worn daily to prevent fractures in patients who have established osteoporosis.
Diagnosis & Management
The NOF recommends a detailed history and physical exam, bone-density assessment and using the World Health Organization’s 10-year fracture probability assessment tool. All postmenopausal women should be evaluated for osteoporosis risk factors and, if necessary, undergo bone-density testing by densitometry.
DXA or dual-energy x-ray absorptiometry, which measures bone mass in the hip and spine, is the gold standard for diagnosing low bone mass. A DXA may be ordered if there are risk factors for low bone mass and the patient is premenopausal. Risk factors include, but are not limited to, smoking, alcohol intake, low vitamin D, anorexia and bulimia, genetic factors, hyperthyroidism and hyperparathyroidism, malabsorption, blood disorders, renal failure and certain medications. Patients who undergo bone density testing via DXA and have osteopenia may then benefit from FRAX calculation to determine their fracture risk and if therapy should be started.
The two main categories of drug therapies for low bone mass are antiresorptive (prevent bone destruction) and anabolic agents (build bone mass). Antiresorptive agents include bisphosphonates (i.e., Fosamax, Actonel, Boniva, Reclast), calcitonin, estrogens and progesterones, and Evista. The commonly used anabolic drug is parathyroid hormone or Forteo. All of these drugs have shown efficacy in reducing fracture risk. Not all the agents are appropriate for every patient, and decisions for therapy should include discussions of risks and benefits relative to the patient’s medical history and severity of bone loss.
Prevention of osteoporosis is possible through adequate calcium and Vitamin D intake and minimal lifestyle changes. Diagnosis is easily established by measuring bone mineral density by DXA, which all women age 65 and older should undergo regardless of clinical risk factors. Younger postmenopausal women should be tested based on their clinical risk profile, and women with fractures after age 50 should be tested. Based on the results women and their physicians can plan therapies to lower the risk of fractures.
Image from: www.fortworthdental.com
Rebecca Terry, M.D., graduated from Transylvania University and the University of Louisville School of Medicine. Her residency training was at the University of Oregon. Dr. Terry was a founding partner of Women First of Louisville PLLC and her current practice focuses on gynecology. She is also certified in clinical bone densitometry and has been named in Louisville Magazine as one of Louisville’s “Top Docs.” Her special interests include laparoscopic surgical procedures, conservative management of uterine bleeding problems, diagnosis and treatment of abnormal pap smears, osteoporosis and gynecologic urology, management of menopause and perimenopause, treatment and prevention of osteoporosis and preventative health care services.