ANSWER: Yes, strontium will increase your bone density; a better question is whether strontium will reduce your likelihood of getting a fracture, and that answer probably is yes. However, the best question is whether the risks outweigh the benefits, and that answer is a bit unclear.

Strontium is a heavy and dense element, but it is treated like calcium by your body, and is placed into your bones. That makes the bone density appear greater by the standard DEXA test, and the rising bone density does not correlate with the degree of fracture reduction.

Longer studies in Europe did show that strontium reduced the risk of vertebral fractures; however, a European Medicines Agency (similar to the U.S. Food and Drug Administration) committee recommended against the use of strontium ranelate (which is not available in the United States) unless there are no other approved medicines that can be used, and that it should not be used in people with a history of heart attack, angina or stroke. This is because some data showed increased risk of heart disease and blood clots.

Strontium can be purchased in the U.S. as a supplement; however, it is not strontium ranelate; has not been tested for safety and efficacy; and its risks on the heart and on blood clotting are unknown. Most supplements sold in the U.S. are not independently tested for purity. I recommend against taking strontium supplements.

The osteoporosis pamphlet furnishes details on how to prevent this universal condition. Readers can obtain a copy by writing: Dr. Roach — No. 1104, 628 Virginia Dr., Orlando, FL 32803. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name address. Please allow four weeks for delivery.

DEAR DR. ROACH: My husband starts radiation treatment next week for stage one cancer on his vocal chord. Does radiation negatively affect the immune system the same way chemotherapy does? Should I be looking out for people who don’t vaccinate? — H.T.

ANSWER: Radiation can affect the immune system when it is given to large areas of the body, since the immune system cells are largely sensitive to radiation. Whole-body radiation rarely is used now, except in people planning for bone-marrow transplant. By contrast, localized radiation does not adversely affect the immune system to anywhere near the degree that chemotherapy can, since the bone marrow, where the immune system cells live, is diffuse throughout the large bones of the body.

As far as avoiding unvaccinated individuals, people who are unvaccinated and who are healthy do not pose a risk. It is in an outbreak of vaccine-preventable disease (there have been localized outbreaks of measles and mumps in the past year, and there are seasonal outbreaks of influenza) that unvaccinated people are much more likely to be infectious. So anyone with immune system disease (such as chemotherapy or whole-body radiation) should avoid people with potentially infectious illness. Caregivers of people with severe immune disease certainly should be immunized according to current guidelines. Even elderly people whose caregivers are immunized for flu get flu less than those whose caregivers are not.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.