This is a presentation to the Greater NY Celiac Support Group, Columbia-Presbyterian Medical Center, October 9, 1996, summarized by Sue Goldstein
Normal bone is similar in appearance to a sea sponge. It is composed of thick interconnected plates separated by spaces. In osteoporosis, the plates gradually become thinner, then perforate and eventually disappear. Due to this deterioration in the architecture of bone, it becomes less able to withstand the stresses and strains of everyday life. A person may have osteoporosis and never have a broken bone. However, if they have a fall or other injury, they are more likely to break a bone than someone with normal bone.
In this country, approximately 1.5 million fractures occur every year. These include fractures of the vertebrae, the wrist, and the most dangerous and expensive of all - the hip fracture. As a consequence of hip fractures, more than 60,000 patients a year enter nursing homes. There are also many deaths during the first year after a hip fracture. It is much easier to prevent osteoporosis than to treat it once it has developed. Therefore, it is important to make the diagnosis as early as possible.
The factors that cannot be changed include:
Risk factors that can be changed:
By the time a person reaches their twenties, they have probably achieved their peak bone mass, which is a major determinant of osteoporosis later in life. In general, people who have high peak bone mass at maturity will end up with the most bone and fewer fractures later in life. Once the forties are reached, bone mass begins to decrease gradually by 1-2% per year. Women also go through a period of more rapid bone loss during the 5 to 10 years after menopause. Calcium deficiency impacts on bone density early in life because you will make less bone, and later in life when you will lose more bone than an individual with enough calcium available.
The incidence of osteoporosis in patients with Celiac Disease varies somewhat. The incidence is higher with more severe disease and older age at diagnosis. When children present with Celiac Disease, they usually have evidence of delayed or poor growth, and bone density, if measured, is low. When a gluten-free diet is maintained, there is usually an increase in bone mass, and the growth rate usually improves. Some studies suggest that children with Celiac Disease who are diagnosed at a young age and treated effectively will have normal bone mass when they reach adulthood.
Adults who have had lifelong undiagnosed Celiac Disease are more likely to have lower bone density than the average person their age. They are significantly more likely to already have had broken bones than are age and sex matched controls.
Patients with Celiac Disease may also have a different bone disorder called osteomalacia. Osteomalacia differs in several respects from osteoporosis. In osteomalacia, the amount of bone may be normal, but there is less mineral in the bone. Bone formation is a two-step process. Bone is first made as soft tissue; after the bone has been laid down, calcium and phosphorus are deposited in the tissue, and it hardens. In osteomalacia, less calcium and phosphorus are deposited into bone. This makes the bone soft and more pliable. In children, the long bones of the legs will bend and bow, which is called rickets. In contrast to osteoporosis, there are usually symptoms with osteomalacia. The bones may ache and feel sore to the touch. For example, it is common to have hip or heel pain when you stand. Fractures do occur, but they tend to be a little different from osteoporatic fractures. It is important for the physician and the patient to know whether they’re dealing with osteoporosis or osteomalacia, because they are treated differently, and certain therapies that might make osteoporosis better might make osteomalacia worse. The definitive diagnosis of osteomalacia is made by bone biopsy, where excess unmineralized bone can be seen, although tests of blood and urine may also be helpful.
A plain x-ray will not detect bone loss until 30% of the bone is gone; bone densitometry will detect bone loss much earlier. Bone densitometry is also easy and fast; depending on the manufacturer or age of the scanner, it will take anywhere from five to thirty minutes. Another strength of bone densitometry is its accuracy; if you do sequential bone densities, you can detect relatively small changes with a fair degree of certainty. Bone densitometry also has very low radiation exposure. The two most common types of bone density machines in use today are made by Hologic or Lunar. It is very important to try and be measured on the same machine, since measurements made on different machines do not always correlate well.
Patients with Celiac Disease should be evaluated for osteoporosis. Bone densitometry will tell you whether you have osteoporosis or not, and how you compare to other people your age. Certain blood tests are also essential. The concentration of calcium in the blood should be measured, because it is frankly low in many Celiac Disease patients. Phosphorus may also be low, and this blood test is helpful to the physician in evaluating the degree of involvement of your bones when you have Celiac Disease. The 25-hydroxyvitamin D blood level, which reflects the body’s stores of vitamin D should also be measured. Parathyroid hormone blood levels should also be measured; this test helps the physician know if the Celiac Disease is well controlled, whether there is a lot of bone loss going on, and whether the patient is getting adequate calcium or not.
It is also helpful to have a urinary calcium test, which involves a 24-hour urine collection, which helps in determining whether the patient is getting adequate calcium. Bone turnover markers are more specialized tests that assess whether there is a lot of bone loss going on. It has been shown that patients with Celiac Disease do have higher levels of bone turnover markers.
Calcium supplements are important, and may be necessary even in those patients who have a good response to the gluten-free diet. Celiac Disease patients lose more calcium in bowel movements than normal people do, and there is a certain amount of calcium that is lost in the urine whether you have Celiac Disease or not. Calcium is necessary for a myriad of body processes, and if it doesn’t come from the diet or supplements, it is taken from the bones.
If the vitamin D level is low, supplements can be taken. Sometimes plain vitamin D doesn’t work, because it is not well absorbed. Other types of vitamin D can be prescribed by your physician that are more easily absorbed. Making sure you get a reasonable amount of sunlight exposure is also a good way to get more vitamin D.
Women with Celiac Disease who go through menopause should strongly consider taking estrogen, which will protect them from the additional bone loss that occurs with estrogen deficiency.
There are other newer therapies for osteoporosis. None of them have been evaluated in patients with Celiac Disease. The new Merck drug, Fosamax (Alendronate), is absorbed mainly in the stomach, and should be absorbed in the patient with Celiac Disease. It does not contain gluten, but does contain lactose. The decision to institute Fosamax therapy is a very individual one that should be reached between the Celiac Disease patient and their doctor after a careful evaluation to make sure that there is no evidence of osteomalacia. Fosamax may make osteomalacia worse. Moreover, at this time we don’t really know if Fosamax is effective. The other agent that is approved for osteoporosis is calcitonin, which is available in a nasal spray. Calcitonin probably won’t hurt anybody, but there is no information available about whether it helps. Newer agents that act by different mechanisms to increase bone density are now in clinical trials.
A: The diagnosis is helped by the blood tests that we discussed, but the only way to make a firm diagnosis is with a biopsy of the bone. Osteomalacia is treated with a lot of vitamin D and calcium. If the patient cannot absorb vitamin D, a way to get enough vitamin D has to be found. Since vitamin D is made in the skin, you can make enough vitamin D from sitting out in the sun 15-20 minutes a day. In northern latitudes like ours, there is not enough sunlight during the winter months to form sufficient vitamin D. Therefore, it is wise to get a little extra sunlight in the summer.
Q: Is weight-training beneficial for increasing bone density?
A: Exercise studies are very difficult to do and evaluate. The best data has shown walking to be the best exercise for increasing bone density. Weight-training can increase strength, flexibility and muscle tone, and impedes aging, so it is encouraged, although it hasn’t been proven to directly increase bone density.
Q: Would a CAT scan be a good test to measure bone density?
A: I do not recommend CAT scans, which have very high radiation. Moreover, the hip is not usually measured, which is very important, particularly in older people. Also, it is not as reproducible as DEXA when yearly tests are ordered to see if you are responding to therapy.
Q: How much calcium should be taken in one dose?
A: The most efficient absorption of calcium is from a 500 mg. dose. Taking supplements in 500 mg. doses during the day is best. Calcium carbonate should be taken with food for best absorption. Calcium citrate does not need to be taken with food.
Q: What are the recommended daily allowances of calcium?
A: Men and premenopausal women and postmenopausal women taking estrogen need a total of 1000 mg. of calcium a day from dietary sources or supplements. Postmenopausal women who are not on estrogen need 1500 mg. of calcium a day. Before age 10, children need 800 mg. a day. Adolescents, from age 10 and up, require 1500 mg. a day. Celiac patients may need more than the recommended allowances; this would need to be determined on an individual basis.
Q: Are magnesium and zinc supplements beneficial for bone? What about boron?
A: Magnesium would be helpful only if the patient has magnesium deficiency; otherwise there is no evidence that it improves the absorption of calcium or the effect of calcium on bone. I’m not aware of any evidence of zinc or boron having any benefits.
The purpose of this copyright is to protect your right to make free copies of this paper for your friends and colleagues, to prevent publishers from using it for commercial advantage, and to prevent ill-meaning people from altering the meaning of the document by changing or removing a few paragraphs.