Colds: caused by virus or being cold?

Q. My daughter insists you get colds from catching a virus, NOT from being cold, wet, not fully dressed or walking in the rain. Her beautiful 15-year-old son does not use an umbrella and likes to wear just a T-shirt out in chilly weather. She is so sure that only a virus can cause a cold that she never tells him to take an umbrella or a jacket. It makes me frustrated.

A. Folk wisdom maintains that becoming chilled — especially if clothes, hair or feet get wet — is likely to lead to a cold. Researchers have dismissed this belief as an old wives' tale.

Scientists have squirted cold viruses into the noses of volunteers and then exposed them to cold temperatures to see if this makes a difference. Studies that were done decades ago did not find an effect.

More recently, though, researchers in Wales had 90 volunteers put their feet in cold water for 20 minutes. Ninety others served as control subjects. Those who were chilled with cold water were more likely to report cold symptoms over the next five days (Family Practice, December 2005). The investigators concluded that the old wives may have been right after all, though they are not quite sure why.

Q. I have been taking thyroid hormones (first Synthroid and then Levoxyl) for more than 15 years. My doctor has recently started lowering my dose because he is concerned that the extra thyroid might weaken my bones.

Ever since the dosage was reduced, I have had many troubling symptoms. My cholesterol is going up, and so is my weight. I am tired, cold and depressed most of the time. My skin is dry, my fingertips have painful cracks, and my nails are splitting. My hair is thinning, and my eyebrows are fading away. Along with all that, I have absolutely no interest in sex. What can I do?

A. Although excess thyroid hormone can weaken bones and contribute to osteoporosis, getting the dose just right is essential for good health. All the symptoms you have described could be linked to insufficient thyroid activity.

We are sending you our Guide to Thyroid Hormones with information on how to interpret thyroid lab results as well as treatment options so you can discuss this with your doctor.

Q. I need more information about the generic for the epilepsy drug Keppra.

A. Generic drugs are supposed to be identical to their brand-name counterparts. We have received a couple of troubling reports about this epilepsy medicine, however. One reader wrote: "I take Keppra, and recently I was switched to a generic version. Several days after I began taking the generic pills, I suffered multiple seizures. I had to go back on name-brand Keppra." When we asked the Food and Drug Administration about this problem, we were told that the generic formulation was unlikely to be responsible for seizures.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them c/o King Features Syndicate, 888 Seventh Ave., New York, NY 10019, or via their Web site: www.peoplespharmacy.org