Dear Doctor: My teenage daughter got the HPV shot. Should my son get it as well?

Dear Reader: The vaccine against HPV infection was initially created for females under the age of 26 to reduce the risk of cervical cancer. Human papilloma virus, or HPV, has been shown to be the cause of virtually all cervical cancer cases in women. Thus, if you decrease the possibility of infection with HPV, you would decrease the rates of cervical cancer, a disease diagnosed in 12,000 to 13,000 women in the United States each year. That's all for the good among females, but your question -- a logical one -- was about the benefit to males.

In men, HPV infection can lead to penile cancers, anal cancers and oral cancers. It has been estimated that 70 percent of cancers of the oropharynx are related to HPV. If that is the case, HPV-related cancers are diagnosed in about 11,000 men in the U.S. per year, so the vaccine would appear to have benefit for males as well.

The other benefit of the vaccine -- for both men and women -- is the prevention of genital warts. These warts are not life-threatening, but they're more than a nuisance to the people who get them. The Gardasil vaccine, the most common HPV vaccine, protects against four types of HPV. In addition to protecting against HPV types 16 and 18, which cause many HPV-related cancers, the vaccine also protects against types 6 and 11, which cause 90 percent of genital warts.

The benefits of giving boys the HPV vaccine appears to be enough to recommend giving the vaccine to your son. In addition, by giving your son the HPV vaccine, you will also decrease the likelihood that the virus will be passed on to other people. Providing the vaccine to boys nationwide will lead to less HPV in the community, which will in turn lead to a decrease in cervical, penile, anal and oral cancers.

The biggest problem with the HPV vaccines is the rate of vaccinations. Only 6 of 10 adolescent girls have started the HPV vaccine series, and only 5 of 10 adolescent boys have started it. As there is a two- to three-shot regimen for these vaccines, I can understand if your son does not want to get the vaccine simply to prevent a hypothetical cancer or wart.

However, as a society, we vaccinate against many other illnesses at a much higher rate even when the incidence of those illnesses is quite low. HPV is a very common infection and leads to multiple cancers and genital warts. I'm glad your daughter received the vaccine. Your son should get it too.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: While my wife and I were working in the garden, she got dizzy and couldn't understand what I was saying. It went away after a few minutes, but I took her to the ER anyway. The doctors said she had a TIA. What is that, and is it dangerous?

Dear Reader: Your wife experienced a transient ischemic attack, or TIA. Also known as a mini-stroke, a TIA happens when part of the brain is temporarily deprived of blood flow.

You were right to seek immediate medical help. The symptoms of a TIA and those of a major stroke, which is the fifth-leading cause of death in the United States, are quite similar. And though the effects of a TIA are temporary -- that's the "transient" in the name -- that doesn't mean they're harmless.

First, let's talk about what's going on.

Ischemic strokes occur when a blood vessel in the brain becomes blocked, often by a blood clot. As a result, the part of the brain that is fed by that vessel is starved of blood. Since blood carries oxygen, which is vital to survival, it takes just a few minutes for brain cells to begin to die.

Unlike in a major ischemic stroke, where the blockage persists and damage can be permanent, a TIA resolves quickly. Sometimes it takes just a few minutes, and sometimes the effects can last up to 24 hours. When the TIA is over, the person feels normal again.

Symptoms of a TIA include the dizziness and cognitive lapse that your wife experienced. Additional symptoms may be a sudden headache, impaired vision, numbness or weakness in the face or limbs, garbled speech, and loss of balance and coordination.

The federal Centers for Disease Control and Prevention classify a TIA as a medical emergency. Although impairment due to a TIA is temporary, the event itself is a warning sign that needs to be addressed. A person who has experienced a TIA is at increased risk of a full-blown stroke, particularly in the first few days after the attack. However, with prompt treatment, as well as certain lifestyle changes, you can decrease the chance of a future stroke.

Your wife should see her primary care physician to discuss what happened and to begin treatment. This typically includes taking aspirin, a blood thinner that makes your platelets less likely to clump together. Aspirin should be initiated and continued under a doctor's supervision.

The good news is that your wife can also make some simple lifestyle changes to decrease her risk of another episode:

-- Keep blood pressure under control.

-- Don't smoke, and avoid secondhand smoke.

-- Maintain a healthy weight.

-- Eat plenty of fresh fruits and vegetables.

-- Exercise regularly.

-- Avoid stress.

-- Get enough sleep.

-- Limit alcohol.

Even better news: Every one of these suggestions will make you healthier, too.

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: Some women, and juries, say that talc causes ovarian cancer, but doctors say it doesn't. Where's the evidence either way?

Dear Reader: Talc is a mineral composed of magnesium and silicate. Talcum powder, commonly known as baby powder, was first marketed by Johnson & Johnson in 1894. It was first used, and is still used, to prevent diaper rash. The concern regarding ovarian cancer is that talc may pass into a woman's uterus and then move up the fallopian tubes during menses. In fact, talc particles have been found in the fallopian tubes of women who have used talcum powder on sanitary napkins or pads.

The suggestion that talcum powder may lead to ovarian cancer first came from case-control studies. The largest of these was a combined analysis of eight different studies that compared 8,525 women (cases) who had ovarian cancers and 9,859 women (controls) who did not. In the studies, researchers asked women if they had used talcum powder in the genital area previously and how frequently. The authors concluded that the use of genital powder was associated with a 20 to 30 percent increase in some types of ovarian cancer.

One problem with that analysis is that some powders contain cornstarch, not talc. The other problem is that of recall bias. Women with ovarian cancer may report previous use of powders because they believe there may be a link between the powder and their ovarian cancer. Further, the authors did not find any dose response associated with powder use, meaning that they did not find a link between greater amounts of powder and ovarian cancer.

Other case-control studies have come up with similar conclusions. Based on such data, many lawsuits have contended a link between talcum powder and ovarian cancer. Two of these lawsuits have led to judgments of $72 million and $55 million against Johnson & Johnson.

One difficulty with analyzing statistical links to ovarian cancer is that the disease is somewhat rare; over her lifetime, the average woman has only about a 1 percent chance of developing it. To truly study a potential link between ovarian cancer and talcum powder, you would need large studies. You would also need prospective studies. A prospective study in this case would assess talcum powder use and follow women over time to see if they developed ovarian cancer.

Several studies have attempted to do this. The Nurses' Health Study included 78,683 women followed for nearly 13 years. These women were asked about their use of talcum powder and, over the course of 13 years, 307 cases of ovarian cancer were found. Note that researchers did not find talcum powder to be associated with ovarian cancer, although they did find a 9 percent increase among women who used talcum powder.

The Women's Health Initiative included 61,000 women followed for more than 12 years. In that study, researchers also found a minimal increase in ovarian cancer, but not a statistically significant one. The biggest problem with these prospective studies is that they need to be even larger and longer.

It's possible that there is a minimal increase in ovarian cancer among menstruating women who use talcum powder. However, this may have more historical relevance than topical relevance because fewer women are using talcum powder today than in years past. If you do use a genital powder, cornstarch powder would be a good alternative to talc.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)