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Madhavi Garimella M.D.: Understanding Osteoporosis

on March 4, 2016 - 6:02am

By MADHAVI GARIMELLA, M.D.
Medical Associates of Northern NM

What is osteoporosis?
Osteoporosis which means “porous bone” is a condition of weakening of the structure of the bone leading to an increased risk for fracture. Many people have osteoporosis and do not know about it as they have no symptoms at all.

Osteoporosis does not cause any pain unless you have a fracture.

Why should we worry about osteoporosis?
Osteoporosis is a major cause of morbidity in older Americans. A hip fracture can cause quite a setback in terms of costs both in terms of time, money and morale due to surgery and rehabilitation.

Some facts about osteoporosis:
The National Osteoporosis Foundation states:

  • Of the estimated 10 million Americans with osteoporosis, about eight million or 80% are women.
  • Approximately one in two women or 50% over age 50 will break a bone because of osteoporosis.
  • A woman’s risk of breaking a hip is equal to her combined risk of breast, uterine and ovarian cancer.

Why do we have osteoporosis?
Bone in our body is being constantly remodeled. Old bone is removed and new bone is laid in its place.

We build the maximum bone in our teens and 20s and reach “peak bone mass” in our “bone bank” around 30. Building bone mass depends on a lot of factors- gender, race, exercise, diet to name a few. (It is thus important that we emphasize healthy eating habits and exercise to children and adolescents). As we grow older, we lose more bone than we gain. The bone is more “holey” or porous as it is less dense.

Can men have osteoporosis too?
Women are more prone to osteoporosis as there is a rapid decline in the female hormone estrogen at menopause. Estrogen is one of the major bone building hormones. While men do not have such a rapid decline in hormones, they too can have osteoporosis. Certain medical conditions as well as medications and life style choices like smoking and alcohol can increase the risk. The endocrine society suggests screening men after the age of 70, as age is also considered a risk factor.

How do I know if I am at risk for osteoporosis?
Post menopausal women are at risk for osteoporosis. You are at risk even if you had early menopause surgically . People at additional risk are those with a family history of osteoporosis, taking certain medications like steroids for more than three months, smokers, drinking more than three servings of alcohol a day, White or Asian, with a small frame and those not getting enough physical activity.

What can I do to prevent it?
You can minimize your risk by making sure you follow a healthy lifestyle with adequate calcium, vitamin D and exercising every day with attention to weight bearing or resistance exercises like walking, jogging, skiing and even going up and down stairs.

The story about calcium keeps changing. How much calcium and vitamin D do I actually need?
It is recommended that women up to age of 50 get about 1200 mg a day and above age 50 about 1200-1500 mg a day. We get about 300 mg of calcium daily from all food sources. It is best that the balance of calcium comes from food sources for optimal absorption. A cup of milk or yoghurt supplies 300 mg, however vegans and lactose intolerant people need not despair. Green vegetables are great sources of calcium too. For example one cup cooked collard greens contains 358 milligrams of calcium, one cup of cooked spinach has 240 mg and one cup of mustard greens has about 150 mg of calcium. So you could vary your diet and make up the requirement just by eating healthy without needing to take a supplement.

Vitamin D is important to help absorb calcium from the gut. The recommendations are for adults under the age of 50 should get 800 IU (international units) of vitamin D each day. Adults over the age of 50 need 800 to 1,000 IU daily.

Can I take too much calcium or Vitamin D?
Yes, taking more than 1200 mg of calcium per day will not necessarily build more bone. Your body gets rid of extra calcium which then predisposes to kidney stones.
Similarly you could develop toxicity by taking too much vitamin D as it is stored in the body in fat cells and can accumulate.
Generally doctors recommend a blood level of greater than 30 ng/ml

When and how do we treat osteoporosis?
Your doctor reviews your bone density scan to determine need for treatment. She/he may decide that you would benefit from treatment in addition to adequate vitamin D, calcium and exercise if you have osteoporosis based on your scan. Your doctor could additionally recommend treatment based on your risk for fracture, even if you do not have osteoporosis and just have osteopenia. This risk can be calculated using a model called FRAX.

Since osteoporosis is caused by greater bone loss than bone formation, the medicines that are used target these areas. These are generally considered first line and are called anti-resorptives.

The most popular medicines belong to a family called bisphosphonates. These medicines suppress bone loss and can thus prevent fractures. They are alendronate (Fosamax®), risedronate (Actonel®), ibandronate (Boniva®) and zoledronic acid (Reclast®), which can be taken orally or given intravenously. Another drug with a similar mechanism of action which has been recently approved is denosumab (Prolia®). This is given under the skin every six months and works by blocking the cells which breakdown bone. Estrogen and estrogen like agents – raloxifene (Evista®) also work similarly.

Bone building agents used in severe osteoporosis include parathyroid hormone (teriparatide) /Forteo® This is a daily shot taken upto two years which is reserved for cases of severe osteoporosis or failure to respond to any of the first line agents.

I have heard that these medicines have many side effects and are causing fractures. Are they safe for me?

As with every other medication, these medicines have rare immediate reactions like rashes and other side effects associated with long term use. There have been long term concerns about jaw necrosis. The newest concern has been of fractures occurring with minimal or no trauma such as walking or standing, making us worry that medicines which are supposed to prevent fractures are actually causing them.

The theory behind these fractures is that these drugs which prevent bone breakdown are interfering with the body’s natural ability to heal micro fractures and repair itself. Thus, we may build thick bone, which need not necessarily be healthy bone and is brittle.

However the fact remains that typical hip fractures far outweigh the number of atypical femur (thigh bone) fractures.
The incidence of atypical fractures increases beyond 5 years of taking the drugs. The risk is 1 per 1000 after 6 years and 2.2 per 1000 after the 7th year in a study published in the Journal of the American Medical Association in February 2011. In a different study published in the New England Journal Of Medicine in May of 2011 where 1.5 million women over 50 with fractures of any cause were analyzed, the incidence of atypical fractures was 76 or an absolute risk increase of about 5 in 10,000.

This is a very small number compared to the number of fractures prevented. However there is no doubt that we should be aware of this potential side effect and you should discuss either a “drug holiday” or need to continue treatment with your doctor after 5 years of treatment with these drugs.

Interestingly there are “side benefits” to taking these drugs which have been noted in a few observational studies like reduction in breast, colon and gastric cancer, stroke and overall mortality. However, just as this should not be the reason to take the medications, neither should the fear of side effects deter you from taking the medications if you would benefit from them.

Everyone has a different risk and it is best to discuss with your doctor as to what would be the best choice for YOU and reevaluate periodically.

 


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