Do I need to get a Pap test every year?

DEAR DOCTOR K: I've had a Pap test every year for 20 years, since I was about 25. It's always normal. Do I still need one every year?

DEAR READER: The answer used to be yes. The reason was that doing the test often would help catch cancer of the cervix at its earliest and most curable stage. However, studies showed that less frequent Pap tests for younger women caught just as many early cancers. The studies also showed that many older women with repeatedly normal Pap smears (like you) had an extremely low risk of ever getting cancer of the cervix.

My father has Alzheimer’s disease. Does that mean my children and I will eventually develop it too?

DEAR DOCTOR K: My father has been diagnosed with Alzheimer's disease. Does that mean that my children and I will eventually develop Alzheimer's too?

DEAR READER: Many people worry that if a parent had Alzheimer's disease, they are doomed. But that's not true. Having a first-degree relative (parent, sibling or child) with Alzheimer's disease increases a person's risk by about 30 percent. That sounds like a lot, and therefore sounds scary. But what you really want to know is: What is my risk in the first place? If it's a very low number, then raising a low risk by 30 percent won't be a big deal.

Why do best practices get reversed so often in medicine?

DEAR READERS: In yesterday's column, I answered a reader's question about why doctors seem to change their minds about the best treatments for medical problems. I said that we doctors keep changing our minds because we're human. We sometimes believe things that seem reasonable and for which there is some evidence. But then we find out, as more and better research is done, that we were wrong.

Why do doctors keep changing their minds about the right thing to do?

DEAR DOCTOR K: I have diabetes, and my doctor used to tell me my fasting blood sugar level needed to be below a certain number. Now, he says it's OK if it's higher. Why do doctors keep changing their minds about the right thing to do?

DEAR READER: We doctors keep changing our minds because we're human. Which means that we sometimes believe things that seem reasonable and for which there is some evidence -- only to find out, as more and better research is done, that we were wrong.

Does the immune system really change with the seasons

DEAR DOCTOR K: A friend heard about a study that said a person's immune system changes with the seasons. That seems incredible to me. But if it's true, it's fascinating. Do you know what she is talking about?

DEAR READER: I think I know the study she is referring to. Before describing what it found, it's worth talking a bit about the immune system and also about genes.

Should I take antioxidants?

DEAR DOCTOR K: It seems like several years ago all my friends were taking antioxidant pills. Now I don't hear about antioxidants as much. Are they worth taking?

DEAR READER: Here's what we know, and here's what is still controversial. The cells of our body are full of chemicals interacting with other chemicals. In the process of getting the energy they need to survive and carry out their functions, cells naturally produce chemicals called "free radicals." Just as political free radicals can sometimes damage society, chemical free radicals can damage body tissues.

What could be causing my painful urination?

DEAR DOCTOR K: I'm a woman in my 50s, and every so often it is painful for several days when I urinate. The doctor tests me, says I don't have a urinary tract infection, and that there's nothing to do. It's true that it goes away, but I'd like some relief when it hurts. Is there anything I can do?

DEAR READER: Urinary tract infections are a common cause of painful urination, but there are other causes as well. And those other causes can be treated. Here's what you need to know before you talk again to your doctor.

Is red wine good for heart health?

DEAR DOCTOR K: I've heard that drinking red wine, or any alcoholic beverage, in moderation is "heart-healthy." Is it true, and is red wine any healthier than other alcoholic beverages?

DEAR READER: There are many studies of the two questions you ask. As for the first question, most studies have found that moderate drinkers are less likely to develop Type 2 diabetes and heart disease. That's when moderate drinkers are compared either to non-drinkers or to heavy drinkers.

Does the Mediterranean diet improve brain health?

DEAR DOCTOR K: I know that the Mediterranean diet is supposed to improve heart health. Recently I heard it also improves brain health. Is that pretty well established? Of all the organs I want to protect, my brain is "numero uno."

DEAR READER: I agree with your priorities regarding organs: My brain is "numero uno," too. And I do think the evidence is strong that the Mediterranean diet does protect the brain. This diet emphasizes fruits, vegetables, grains, beans, nuts, fish, poultry, olive oil and wine.

Should I try testosterone treatment to treat low-normal testosterone?

DEAR DOCTOR K: I'm a 68-year-old man who has been feeling more tired and less "sexy" over the past several months. My doctor says my blood testosterone level is normal, but "low normal" -- a little bit above low. I know that some men take testosterone gel as a treatment for this. My doctor is not so keen on that. What's your opinion?

DEAR READER: I don't know nearly enough about your health or your symptoms to offer you personal advice. But I'll tell you what I think research has shown, at least so far. I'll warn you: It is a controversial area, and I reserve the right to change my mind as new research is published.