WEDNESDAY, May 21 (HealthDay News) -- Men who keep their cholesterol down might also help lower their levels of prostate specific antigen, a protein that can warn of prostate cancer, a new study says.

"Prostate cancer is controlled by the male hormone testosterone. The main molecule that forms testosterone is cholesterol," said Dr. Murugesan Manoharan, an associate professor of urology at the University of Miami Sylvester Comprehensive Cancer Center, who was not involved in the study. "So it is known that prostate cancer is related to testosterone, and testosterone is related to cholesterol."

The study's inference is that by lowering cholesterol, you also lower PSA, which in turn may reduce the risk of prostate cancer, Manoharan said. "Obviously this is a very small study and does not confirm anything, but it is a very good start that could lead to something more at a later point," he said.

The results of the study were expected to be presented Wednesday at the American Urological Association annual meeting, in Orlando, Fla.

For the study, researchers collected data on 1,214 men taking cholesterol-lowering drugs called statins. The researchers found that PSA levels were lower after starting the statins, and the drop in PSA was proportional to the drop in cholesterol.

The results of the study confirm those of a previous study that also found that lowering cholesterol lowered PSA, the researchers noted. If confirmed, the results of the new study would provide more evidence that cholesterol plays a role in the biology of the prostate, the researchers said.

It's still not clear, however, whether lowering PSA with cholesterol-lowering drugs may actually hide developing prostate cancer, Manoharan said.

"Bringing down the PSA levels artificially does not mean necessarily decreasing the chance of developing prostate cancer," he said. "It might just bring the blood test reading down without reducing the risk of prostate cancer. In fact, we could miss the prostate cancer, because the PSA readings are on the lower side."

Manoharan said the new findings need to be studied further. "If statins do, in fact, reduce the incidence of prostate cancer that would be a very good thing," he said.

Two other studies presented Wednesday confirmed that so-called "watchful waiting" of men with a low risk of prostate cancer is a viable option. Watchful waiting is a strategy in which no treatment is given, but the patient is monitored to check the progress of the cancer.

But, the researchers of one of the studies noted that PSA exams and digital rectal exams aren't good predictors of the progress of prostate cancer. They suggest that better monitors of the disease need to be developed.

In another study presented Wednesday, researchers from Johns Hopkins University found that men 75 to 80 years of age with low PSA levels -- less than 3 nanograms per milliliter of blood -- may be able to stop regular prostate cancer screenings.

The researchers found that these older men who have PSA levels below 3 nanograms per milliliter have a low probability of dying from prostate cancer, while men with PSA levels of 3 nanograms or more have an increased risk of dying from the disease.

More information

For more on prostate cancer, visit the National Cancer Institute.

THURSDAY, May 1 (HealthDay News) -- Depression in women and stroke in men are critical factors in the development of Alzheimer's disease, French researchers report.

They analyzed data from almost 7,000 people over the age of 65 in three French cities. None of them had dementia, but about 40 percent had mild cognitive impairment at the start of the study.

They were assessed two and four years later. Of those with mild cognitive impairment at the start of the study, just over 6.5 percent developed dementia over the next four years, about half had no change, and about one-third regained normal levels of cognitive ability.

People with depression, those taking anticholinergic drugs (which influence chemical signaling in the brain), and those with a variation in the ApoE gene (a known risk factor for dementia) were more likely to progress from mild cognitive impairment to dementia.

The researchers also found that risk factors varied according to gender. Men with mild cognitive impairment were more likely to be overweight, diabetic and to have had a stroke. Men who'd suffered a stroke were almost three times more likely to progress from mild cognitive impairment to dementia.

Women with mild cognitive impairment were more likely to be in poorer general health, disabled, suffering from insomnia, and to have a poor support network. Women with depression were twice as likely to progress from mild cognitive impairment to dementia, while women unable to perform routine daily tasks (which would allow them to live without assistance) were 3.5 times more likely to progress to dementia.

Stroke was not a risk factor for women, even though both women and men had similar rates of stroke.

The study was published online in the Journal of Neurology Neurosurgery & Psychiatry.

More information

The U.S. National Institute on Aging has more about Alzheimer's disease.

MONDAY, April 21 (HealthDay News) -- The first signs that men are at higher risk of heart disease than women appear during the adolescent years, according a new study that tracked boys and girls through their teens.

"This is not what we would have predicted," said Dr. Antoinette Moran, chief of pediatric endocrinology and diabetes at the University of Minnesota Children's Hospital, and lead author of the report in the April 22 issue of Circulation. "Because boys lose fat and gain muscle in adolescence, while girls add body fat."

At the start, 11-year-old boys and girls were similar in body composition, blood pressure and blood levels of lipids (fats). As expected, the percentage of body fat decreased in the boys and increased in the girls over the adolescent years.

Yet the study of the 507 Minneapolis school children found that between the ages of 11 and 19, levels of triglycerides, a type of blood fat associated with cardiovascular disease, increased in the boys and dropped in the girls. Levels of HDL cholesterol, the "good" kind that helps keep arteries clear, went down in boys but rose in girls.

Blood pressure increased in both, but significantly more in boys. And insulin resistance, a marker of cardiovascular risk, which was lower in boys at age 11, rose until the 19-year-old men were more resistant than the women.

But excess weight is of major importance in both sexes, Moran said. "Being overweight or obese can cancel out these relationships and cause increased cardiovascular risk for males and females," she said. "Any protection that the young women had was wiped out by obesity."

A recent study found that more than a third of children and adolescents in the United States are overweight or obese.

The study points toward the importance of hormonal factors in cardiovascular disease risk, Moran explained. "We knew that women had extra protection from cardiovascular disease, and we knew it disappeared after menopause," she said. "This adds further weight to the role of hormones by looking at the other end of the age spectrum."

One possible lesson of the study is that it is never too early to start protective measures against heart disease, said Dr. Stephen R. Daniels, chairman of the department of pediatrics at the University of Colorado.

"Studies have used autopsies of young people who died in accidents to show that by the late teens, the kind of lesions we know cause heart attacks and strokes are in the process of developing," Daniels said. "So, in some ways, our best opportunity to prevent heart disease is to look at children and adolescents and start the preventive process early."

Fighting obesity in the years before adulthood is essential, he said. "Some changes that occur may be due to what is built into the difference between the sexes," he said. "But if you add overweight and obesity, you can increase risk through that mechanism."

More information

Facts about childhood obesity are available from the U.S. Surgeon General.