DEAR DR. DONOHUE: Every summer, I go camping and fishing with three friends. We’ve been doing it for 10 years. I enjoy it, but mosquito bites make it hellish. I’m a mosquito magnet. My friends rarely are bitten, but I am covered with bites. What can I do about it? Someone suggested taking the vitamin thiamine. Does it work? And what works best to stop the itching that drives me crazy? – R.K.

ANSWER: Someone always suggests thiamine to prevent mosquito bites. I haven’t seen any proof that it works.

It’s the female mosquito who bites. She needs blood for the development of her eggs. It’s a survival thing, so don’t be too hard on her.

Some people do attract mosquitoes. Researchers have many theories why this is so. It might be that the mosquito magnets have more cholesterol, uric acid or lactic acid on their skin.

Or they might produce more carbon dioxide, which attracts mosquitoes.

Repellents are the answer for you. Those with DEET are very good. DEET can eat through fishing lines, so beware. It can also damage plastics, rayon, spandex, leather and some paints and varnishes. Another good repellent is picardin, found in Cutter Advanced.

Permethrin kills mosquitoes on contact. It’s put on clothes. It doesn’t harm skin if it gets on it, but skin breaks it down and it loses its effectiveness. You can doubly protect yourself by using a skin repellent and also using permethrin on your clothes.

The antihistamine Zyrtec quells mosquito-bite itching quite well. It’s a prescription drug.

DEAR DR. DONOHUE: I am 6 feet tall. I have a 50-inch chest, 18-inch biceps and big, meaty legs. I feel great all the time. I am an auto-body repair technician, so I am up and down all day long.

I just read your body mass index article. I think they should do away with that. I weigh 245 pounds, and according to the body mass index scale, I am obese. An insurance company refused me for insurance because of that stupid scale. When you praise this scale, you give people the wrong information. This scale might work for pencil-necked, little people, but it doesn’t apply to muscular people. It’s a scale that absolutely stinks. – G.W.

ANSWER: Calm down, will you? I’m on your side.

Body mass index is not an infallible guide to body composition, but it’s better than scale weight. It puts heavily muscled people into an obese range when they shouldn’t be there. For such people, other methods of assessing body composition are more reliable, but they’re expensive and often hard to perform.

Why not appeal to the insurance company? The medical director might yield to your argument.

For the less-well-endowed, body mass index is reliable.

I am a pencil-necked geek. I bet you’ll kick sand in my face if you see me on a beach. Don’t.

DEAR DR. DONOHUE: I would like to tell you what happened to my son so that others can be aware of the problem. He pitches on a baseball team in a teen league. Three weeks ago he complained of shoulder pain in his pitching arm. I thought he overused it, and told him to rest for a few days. The pain didn’t go away but he tried to pitch again. Then his shoulder really hurt. It turns out he had a clot in one of the veins that drains his arm. Now he’s on blood thinners, and there is talk of an operation. His shoulder is OK. What’s this operation? – K.S.

ANSWER: Your son’s condition is not limited to baseball pitchers. It can happen to swimmers, rowers, volleyball players, tennis players and weight lifters. In addition to shoulder pain, the arm is usually swollen.

The combination points to a clot in one of the large chest veins that drains blood from the arm. Often that vein is compressed by a rib high in the chest. If that is the case, the rib must often be removed – probably the surgery that the doctor spoke of.

If the condition is caught early, clot-busting drugs can be used to dissolve the clot.

DEAR DR. DONOHUE: My daughter-in-law says that no one should use deodorant that contains aluminum because the aluminum causes Alzheimer’s disease.

I checked mine. It does have aluminum. Should I stop using it? – A.S.

ANSWER: The link between aluminum and Alzheimer’s disease has been discussed for more than 25 years. To date, no evidence proves there is such an association.

If you want my opinion, I would not throw out the deodorant. I am not one who fears aluminum, in any form, as being a risk for Alzheimer’s disease.

The booklet on Alzheimer’s disease discusses this prevalent and heartbreaking condition in detail. Readers can obtain a copy by writing: Dr. Donohue – No. 903, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com