Understanding Osteoporosis -- the Basics

Medically Reviewed by David Zelman, MD on September 13, 2023
6 min read

Osteoporosis, which means "porous bones," is a condition that causes bones to gradually thin and weaken, leaving them at greater risk of fractures. About 2 million fractures in the US each year are due to osteoporosis.

Although all bones can be affected by the disease, the bones of the spine, hip, and wrist are most likely to break. In older people, hip fractures can be particularly dangerous. Having to stay still for a long time during the healing process can lead to possibly deadly complications, like blood clots or pneumonia.

Of the estimated 10 million Americans who have osteoporosis, at least 80% are women. Experts believe it’s because women’s bones tend to be lighter and less dense and because their bodies go through hormonal changes after menopause that speed up the loss of bone mass.

When people are young, bone in their bodies is broken down and replaced continuously, a process known as bone remodeling. Bone mass usually peaks in a person's mid to late 20s.

Bone loss -- where bone breakdown goes faster than bone buildup -- usually begins in the mid-30s. Bones begin to lose calcium -- the mineral that makes them hard -- faster than they can replace it. Less bone remodeling takes place, and the bones begin to thin.

For women, the loss of bone density speeds up during the first 5 to 7 years after menopause and then slows down again. Scientists believe that’s because of a sharp decline in the body's production of estrogen, which appears to help keep calcium in the bones.

Although some loss of bone density is a natural part of aging, you’re at higher risk for getting the very porous bones and fractures associated with osteoporosis if you:

  • Are thin or have a small frame
  • Smoke, drink more than moderately, or live a sedentary lifestyle
  • Have a family history of hip fracture
  • Had your ovaries removed, especially before age 40
  • Are white or Asian

Certain medical conditions that increase bone breakdown, including kidney disease, Cushing's syndrome, and an overactive thyroid or parathyroid, can also lead to osteoporosis. Glucocorticoids, also known as steroids, also increase bone loss. Anti-seizure drugs and long-term immobility because of paralysis or illness can also cause bone loss.

Your everyday habits -- good and bad -- affect bone health. How do your habits stack up?

  • Vitamin D and calcium. Not getting enough vitamin D or calcium can weaken your bones. The National Institutes of Health recommends adults up to 70 years of age should get 600 IU of vitamin D every day. Over the age of 70, they need 800 IU of vitamin D each day. Men up to age 70 and women up to age 50 need 1000 mg of calcium daily. Men over 70 and women over 50 need 1200 mg of calcium a day.
  • Fruits and vegetables. Eating plenty of fruits and vegetables provides you with magnesium, potassium, and vitamin K -- all good things for bone health.
  • Protein. Very high amounts of nondairy animal protein can weaken the bones. Sufficient protein is important for bone health. Ask your doctor how much protein you should have each day.
  • Caffeine. When used in excess, caffeine can threaten bone health.
  • Alcohol. Excess alcohol intake can decrease bone formation. If you are tipsy from the alcohol, you're more likely to fall. In older people, falls are linked with broken bones.
  • Activity level. Physical activity can help keep bones strong. If you're not an exerciser, ask your doctor for guidance on doing weight-bearing exercises such as fast walking. Ask about lifting weights or other muscle-strengthening exercises. Both types are good for your bones.
  • Smoking. Studies show that smoking is bad for the bones.

To make a diagnosis, your doctor will usually take a full medical history, order a bone density test, and possibly other tests.

During an exam, your doctor will:

  • Look at your age, consider whether women have reached menopause, whether you have ever broken a bone as an adult, your own family history, and your habits such as drinking, eating, and exercise.
  • Ask about which medications you take. Some, such as corticosteroids, can weaken the bones if taken long term.
  • Measure you to see if you’ve lost height. The doctor will inspect your spine. If it abnormally curves forward, that could be a sign that you've already had spinal fractures due to osteoporosis.

A bone density test is noninvasive and measures the concentration of minerals in the bones of the hip, spine and sometimes forearm. Your doctor will compare your results to what’s normal and determine if you have low bone density, known as osteopenia, or osteoporosis.

Your doctor may recommend a prescription drug to help limit bone breakdown and maintain bone density and lower your risk of an osteoporotic fracture. Most of these drugs have been shown to lower risk of fractures in your hips and back.

Examples of bisphosphonate drugs include:

Other drug options to protect against bone loss include:

  • Raloxifene (Evista): an estrogen-like drug that helps increase bone density and reduces fracture risk.
  • Romosozumab-aqqg (Evenity): an anti-sclerostin antibody that works to increase bone formation and reduce bone loss.
  • Abaloparatide (Tymlos) and teriparatide (Forteo): a synthetic form of parathyroid hormone for people with osteoporosis who are considered at high risk for fracture. These medications help build bone density.
  • Denosumab (Prolia, Xgeva): an antibody that prevents the formation of cells that break down bone, resulting in less bone loss.
  • Calcitonon: a naturally occurring hormone that helps prevent fracture and may help slow bone loss.

If you start taking a bone-maintenance drug, be sure your doctor knows about all other medicines you’re on. Some drugs can affect the bones, and your doctor may want to switch you to another drug or adjust the dose.

If you’re taking a bisphosphonate, you may be switched to another drug after 5 years. There’s a low risk of getting a thigh bone fracture if you use them long term.

Hormone replacement therapy (HRT) -- either estrogen alone or a combination of estrogen and progestin -- can prevent and treat osteoporosis.

However, research has shown that hormone replacement therapy increases the risk of breast cancer, heart disease, and stroke in some women. So HRT isn't generally recommended for initial treatment of osteoporosis in most women, because the health risks are thought to outweigh the benefits.

In women who have been on menopausal hormone therapy in the past and then stopped taking it, the bones begin to thin again -- at the same pace as during menopause.

Fractures from osteoporosis often happen at the hip, wrist, and spine. Hip fractures often require surgery. Wrist fractures may need casting or surgery.

Spine and fractures are the most common in seniors. Weak bones can lead to a compression fracture in the vertebrae, the bones that form your spine. Over time, compression fractures can change the strength and shape of your spine. You may lose height or have chronic back pain. In some people, the pain can be severe and can lead to other health problems.

Pain medicine and other therapies can help. Options include:

Two surgical procedures, both minimally invasive, can be done for fracture-related back pain:

  • Kyphoplasty involves inserting a balloon to expand the fractured vertebrae. The space created by the balloon is then filled with bone cement. The balloon is withdrawn.
  • Vertebroplasty involves injection of the cement, but without the use of the balloon.

When considering these procedures, discuss the benefits and risks with your doctor. They can have serious risks, such as the cement leaking, and other side effects, like tissue damage, blood clots in the lung, and respiratory failure.

Fractures due to osteoporosis can interfere with daily activities such as bending, walking downstairs, or cooking. Prompt treatment, physical therapy, and your commitment to a healthy lifestyle can improve your well-being