Reader: I was recently informed that I have very high cholesterol. (I believe the total was 321.) I am now taking pravastatin to try to lower it. I am 72 years old, weigh about 127 lbs., and try to stick to a reasonable diet and get some exercise.

I was also recently diagnosed with hypothyroidism, for which I am taking Synthroid. And, I have also been taking Fosamax for osteoporosis for some years now.

Now, my question is prompted by an article in which the author writes: "Certain health problems, such as hypothyroidism, can increase cholesterol production. Also, some medications that treat conditions like high blood pressure or osteoporosis may adversely affect the balance of good vs. bad cholesterol."

Could my hypothyroidism plus the Fosamax be contributing to my high cholesterol? I'm entertaining the thought of quitting the Fosamax in light of the fact that my bone density has improved hardly any, and is even some worse in the spine. I have also heard reports about Fosamax causing a condition in some individuals where the jaw is literally eaten away. Your advice will be appreciated.

Dr. Zipes: Hypothyroidism, which is caused by a thyroid gland functioning at a rate lower than normal, call definitely he responsible for elevated cholesterol. Taking the Synthroid should correct the hypothyroidism and reduce your cholesterol. Importantly, it may not reduce the cholesterol all the way to an acceptable range and you may still have to take the pravastatin. So be sure to check the cholesterol level again when your thyroid status returns to normal.

Fosamax (generic name alendronate) belongs to a class of compounds called bisphosphonates that are used to inhibit a type of cell called osteoclasts that break down bone. By inhibiting bone resorption, these drugs improve bone density. You are correct that a form of jaw dissolution called "bis-phossy jaw" has been reported. It is named after "phossy jaw," the occupational hazard of those who made matches with white phosphorus without proper safeguards, many years ago. Bis-phossy jaw appears to be due to insufficient blood flow to the jaw causing osteonecrosis, or death of the jaw bone. Fosamax does not seem to have an effect on cholesterol, however. Check with your doctor before stopping the Fosamax.