Exercise cuts genetic obesity risk by 40 percent: study

WASHINGTON (AFP) – Physical exercise can reduce a genetic predisposition to obesity by an average of 40 percent, a new study showed.

The research challenges the notion that an inherited propensity to obesity is impossible to overcome and boosts the case for the benefit of more exercise for anyone looking to shed some weight.

The study, published in this week's Public Library of American Science Medicine journal, is based on examination of 20,430 people living in Norwich, Britain.

It found most of the study's participants inherited between 10 and 13 genetic variants known to increase the risk of obesity, with some inheriting as many as 17 variants, and others as few as six.

Using modelling techniques, the researchers found that each genetic variant was linked to an increase in body mass index (BMI) -- a measure of body size based on both height and weight.

"Each additional genetic variant in the score was associated with an increase in BMI equivalent to 445 grams (1.6 ounces) in body weight for a person 1.70 meters (5.7 feet)," the study said.

For physically active individuals, the increase was just 379 grams (13 ounces).

That was "36 percent lower than in physically inactive individuals in whom the increase was 592 grams (21 ounces) per variant," the research found.

Each additional variant also raised the individual's chances of obesity 1.1-fold, but in physically active individuals, "the increased odds per variant for obesity risk were 40 percent lower."

Ruth Loos of Britain's Medical Research Council Epidemiology Unit, who carried out the research, said the study "challenged deterministic view of the genetic predisposition to obesity."

"Our findings further emphasize the importance of physical activity in the prevention of obesity," Loos said.

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For Bonobo Males, Mom Is the Best Wingman

To most human males, the thought of your mother anywhere near your sex life is probably horrifying. Not so for the bonobo, one of our closest primate relatives. A new study confirms that hanging out with mom boosts male bonobos' chances of getting intimate with a fertile female.

The study found that when their mothers are around, low- to mid-ranking bonobo males get more opportunities to mate. Mothers facilitated sons' presence in their social circle so they were able to interact with more females, and also chased away rival males who might try to break up their sons' blooming relationships.

The mothers aren't just busybodies, say the researchers. In fact, taking an active interest in their sons' love lives helps mothers pass on their own genes.

"If they support their sons, they can have more grandkids," study researcher Martin Surbeck, a biologist at the Max Planck Institute for Evolutionary Anthropology in Germany, told LiveScience.

Bonobo mama's boys

As any newlywed can tell you, parental interest in offspring's reproduction is common. Orcas are known to form strong mother-son bonds, and according to a study published in August in the journal Nature Communications, being born to a high-ranking mom gives male hyenas a reproductive boost later in life.

In primates, mothers have been shown to improve the survival of their daughters' offspring. But mother-son bonds are harder to measure, because most primate males leave their mother's side at puberty. Bonobos, a cousin to chimpanzees, are an exception. Bonobo communities are female-dominated, and males stick with their mothers in adulthood.

Researchers have long known that the status of bonobo males is linked to the status of their mothers, and field observations suggested that moms were taking an active role in facilitating their sons' mating, said Surbeck. To figure out the maternal role, he and his colleagues used DNA information to tease out the relationships between the bonobos in their field area at Salonga National Park in the Congo. Then they observed the bonobos over a 10-month period, watching how often they fought, mated and became fertile.

Maternal matchmakers

They saw that while the primates split into different "parties" during the day, sons stuck with their mothers between 81 percent and 92 percent of the time. When moms weren't around, the dominant male was responsible for about 41 percent of sexual encounters with fertile females. But when the mothers of low-to mid-ranking males were present, that proportion dropped to 25 percent. In other words, moms kept the dominant male from monopolizing the most fertile females, allowing their own sons to mate, too.

Sometimes, the moms interfered, chasing unrelated males away from females or backing up fights involving their sons. Other times, they stood guard while their sons mated, keeping competitors at bay.

But in large part, the mom's role may be more like that of a matchmaker. Since females have lots of social status in bonobo communities, Surbeck said, a mother's presence allows a son to play a more central role in the group. Being in the center of the social group means more interactions with females and more opportunities to mate.

Evolutionary cousins

The study, published this week in the journal Proceedings of the Royal Society B, "confirms largely what we've known for a long time" about the importance of mothers in bonobo communities, said Jo Thompson, the director of the Lukuru Wildlife Research Project in the Democratic Republic of the Congo.

Thompson, who researches bonobos but was not involved in the current study, said the research raises new questions about the influence of a mother's social rank on her son's success, as well about how other family members, like brothers, might influence mating. She also warned that while the current study showed low- and mid-ranking males got to mate more with fertile females when their moms were present, it didn't investigate whether they actually had more offspring.

"This is a good solid study that continues to build on the knowledge we have, and leads to more questions," Thompson said. "The next step is where we really get interesting."

Studying bonobos is important for conservation reasons, as the animals are threatened by habitat loss and poaching, said University of California Los Angeles anthropologist Joan Silk, a primate researcher who was not involved in the study. But because humans share an evolutionary ancestor with bonobos, the studies may also give us hints about our own evolutionary background, Silk said.

"Seeing both chimpanzees and bonobos gives us an idea of the range of possibilities of our ancestors'" behavior and social structure, Silk said. "They help us imagine what early human ancestors might have been like."


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Original Story: For Bonobo Males, Mom Is the Best Wingman
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U.S. Pediatricians Decry Media's Portrayal of Sex

TUESDAY, Aug. 31 (HealthDay News) -- The nation's leading group of pediatricians has issued a strong policy statement directed toward pediatricians, parents and the media on the danger of messages American teens and children are getting about sex from television, the Internet and other media outlets.

The statement, Sexuality, Contraception, and the Media, was published online Aug. 30 and in the September print issue of the journal Pediatrics.

"The media represents arguably the leading sex educator in America today," said Dr. Victor Strasburger, the lead author of the paper. "We do such a poor job of educating kids about sex in sex education classes in school, and parents are notoriously shy about talking to kids about sex. The media picks up the slack."

Seventy percent of teen shows contain sexual content, Strasburger added, "and less than 10 percent of that content involves what anyone would classify as being responsible content. There's no mention of contracting an STD [sexually transmitted disease] or the need to wait to have sex until later."

The United States leads the western world in teen pregnancy rates and American teens have an alarmingly high rate of STDs -- one in four children.

Meanwhile, U.S. children spend seven hours and more a day with various types of often-sexually explicit media, including music, movies, television shows, magazines and the Internet.

"The research shows us that the portrayal of sex in the media is really unrealistic. It's unhealthy. It doesn't consider the consequences of sexual behavior," said Alan Delamater, professor and director of child psychology at the University of Miami Miller School of Medicine. "This is what our kids are growing up thinking. This is what sex is about. To deny its impact is ignorant because there's so much knowledge of it at this point."

Many pediatricians would like to flip the equation and see media outlets introduce more responsible programming.

"Media has an opportunity to continue doing the same old thing, which is to have an adverse effect on child development, or turn it around and shape attitudes and behavior that could have a positive effect on child development," Delamater said.

The statement contains a number of recommendations for parents, physicians and the media.

"We want physicians to ask two media questions at every well-child visit: how much entertainment screen time per day does the child engage in, and is there a TV set or Internet connection in his or her bedroom," said Strasburger, professor of pediatrics at the University of New Mexico School of Medicine. "That takes 20 seconds and may be more important than asking about childproofing or car seats or bicycle helmets."

The authors of the statement ideally would like ads for erectile dysfunction drugs to not be shown on TV until after 10 p.m.

"Half a billion dollars of ads for erectile dysfunction drugs and virtually no ads for birth control pills or condoms or emergency contraception," Strasburger said. "There's not a single shred of evidence that exposing kids to birth control ads or even making birth control available to them makes them sexually active at a younger age. We're doing things completely backwards."

There should also be more attention paid to how kids use social networking sites on the Internet. And parents can use media story lines as teaching tools to discuss sex with their children, instead of having "the big talk," the statement said.

On the more idealistic side, the statement also recommends that advertisers no longer use sex to sell a wide range of products.

"We want parents to realize that kids are spending more time with media than in any other activity but sleeping, and that the media represents a powerful source of information and in this case a powerful sex educator," Strasburger said.

More information

To learn more about children and the media, visit the American Academy of Pediatrics.

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Benefits seen for high-risk women in ovary removal

CHICAGO – Surgery to remove healthy ovaries gives a triple benefit to high-risk women: It lowers their threat of breast and ovarian cancer, and boosts their chances of living longer, new research suggests.

The study is the largest to date to find advantages for preventive surgery for women who carry BRCA gene mutations. Women with the faulty genes have a dramatically higher cancer risk than other women — five times greater for breast cancer and at least 10 times greater for ovarian cancer.

The study, appearing in Wednesday's Journal of the American Medical Association, found benefits for women with two different BRCA gene variants whether they had previously had breast cancer or not.

The results offer more tailored evidence for women considering ovary removal, a surgery that ends fertility, fast-forwards them into early menopause and may contribute to osteoporosis or heart problems later in life.

"It's really critical to have the best information when making such a profound decision," said senior author Timothy Rebbeck of the University of Pennsylvania School of Medicine.

The researchers followed nearly 2,500 women with BRCA mutations in Austria, England, the Netherlands and the United States. All the women were cancer-free at the start. They were watched for an average of four years. Most of the women were younger than 50 at the start of the study.

They got counseling to help them choose between surgery or increased screening to watch for cancers early.

Ten percent of the women chose mastectomy and 40 percent chose to have their ovaries removed; some had both. More than half the women had neither surgery.

The women who chose ovary removal had impressive results:

_1 percent were later diagnosed with ovarian cancer that showed up in cells missed by surgeons, compared to 6 percent of the women who kept their ovaries.

_11 percent were diagnosed with breast cancer, compared to 19 percent of the women who kept their ovaries.

_3 percent of those who had surgery died, compared to 10 percent of the others.

The study also found preventive mastectomy lowered the risk of breast cancer. No breast cancers were seen in the women who had their breasts removed. That may seem unsurprising, but mastectomy can leave behind breast tissue that can turn cancerous.

The study was observational, meaning it can't prove one choice was better than another. Other factors could have caused differences in the women's cancer rates.

But the results will help doctors counsel their patients, said Dr. Virginia Kaklamani of Northwestern University's Feinberg School of Medicine in Chicago, who wrote an accompanying editorial in the journal.

"I'll use it mostly in talking to people considering genetic testing," Kaklamani said. "I can tell them, 'If we know you test positive, there are things to do that will help you live longer.'"

The increased risk for BRCA carriers is frightening. In the general population, about 12 in 100 women will get breast cancer during their lifetimes, compared to about 60 in 100 women who have faulty BRCA genes, according to the National Cancer Institute. For ovarian cancer, the lifetime risk in the general population is a little more than 1 in 100 compared to 15-to-40 in 100 women with BRCA mutations.

For women with a family history of breast or ovarian cancer, the decision to get tested can be agonizing. The $3,300 blood test, while often covered by insurance, can disrupt families, force decisions on childbearing and leave a woman feeling stigmatized. Surgery costs thousands of dollars, not including lost time at work. Without preventive surgery, a woman faces a regimen of mammograms, MRIs and blood tests to look for cancer.

But several signs point to "the beginning of a new era" for high-risk women, said Joanna Rudnick, a 36-year-old Los Angeles filmmaker. She has known for nine years that she carries a breast cancer gene mutation. Engaged and planning to have children, she's also planning to have her breasts and ovaries removed when she's 40. Her documentary "In the Family" tells about her choices and those faced by other "BRCA-positive" women.

With testing more than a decade old, researchers are just beginning to have better data to understand the benefits of risk-reducing surgery. For high-risk women, equally important are the breakthroughs in cosmetic breast reconstruction, laws to prevent genetic discrimination and evolving attitudes toward removing body parts to avoid cancer, Rudnick said. A federal judge recently struck down patents on the two genes held by Myriad Genetics Inc., which may widen research possibilities and testing options.

Rudnick's glad to hear ovary removal may reduce her risk of breast cancer as well as ovarian cancer.

"This is one of the rare silver linings that has been learned from these prospective studies," Rudnick said.

___

Online:

JAMA: http://jama.ama-assn.org

BRCA genes: http://www.cancer.gov/cancertopics/factsheet/risk/brca

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Aging vets' costs concern Obama's deficit co-chair

RALEIGH, N.C. – The system that automatically awards disability benefits to some veterans because of concerns about Agent Orange seems contrary to efforts to control federal spending, the Republican co-chairman of President Barack Obama's deficit commission said Tuesday.

Former Wyoming Sen. Alan Simpson's comments came a day after The Associated Press reported that diabetes has become the most frequently compensated ailment among Vietnam veterans, even though decades of research has failed to find more than a possible link between the defoliant Agent Orange and diabetes.

"The irony (is) that the veterans who saved this country are now, in a way, not helping us to save the country in this fiscal mess," said Simpson, an Army veteran who was once chairman of the Senate Veterans' Affairs Committee.

The Department of Veterans Affairs has also allowed Vietnam veterans to get money for ailments such as lung cancer and prostate cancer, and the agency finalized a proposal Tuesday to grant payments for heart disease — the nation's leading cause of death.

Simpson declined to say whether the issue would become part of his work on Obama's panel examining the nation's debt. He looked to Congress to make a change.

Sen. Daniel Akaka, a Hawaii Democrat who currently chairs the VA committee, said Tuesday he will address the broader issue of so-called presumptive conditions at a hearing previously set for Sept. 23. The committee will look to "see what changes Congress and VA may need to make to existing law and policy," Akaka said in an e-mail.

"It is our solemn responsibility to help veterans with disabilities suffered in their service to our country," said Akaka, who served in the Army Corps of Engineers during World War II. "That responsibility also requires us to make sure limited resources are available for those who truly need and are entitled to them."

Virginia Sen. Jim Webb, a Democrat and Vietnam combat veteran, has also raised questions about the spending. The leading Republican on the committee, North Carolina Sen. Richard Burr, has not responded to several requests for comment on the topic in recent months.

Because of concerns about Agent Orange, Congress set up a system in 1991 to grant automatic benefits to veterans who served in Vietnam at any point during a 13-year period and later got an ailment linked to the defoliant. The VA has done that with a series of ailments with strong indications of an association to Agent Orange, including Hodgkin's disease, soft-tissue cancers and non-Hodgkin's lymphoma.

Other ailments have been added even though and Institute of Medicine review has found they only have a potential association and that they could not rule out other factors. Those maladies include prostate cancer, lung cancer and diabetes. The committee has said that, for diabetes, more powerful influences include family history, physical inactivity and obesity.

The AP found in reviewing millions of VA compensation records that diabetes is now the most frequently compensated ailment, ahead of post-traumatic stress disorder, hearing loss or general wounds. VA officials use a complex formula when awarding benefits and do not track how much is spent for a specific ailment, but AP calculations based on the records suggest that Vietnam veterans with diabetes should receive at least $850 million each year.

Paul Sullivan, executive director for the advocacy group Veterans for Common Sense, said it would be unreasonable for veterans to have to prove on a case-by-case basis that their illness came from Agent Orange. He believes the science supports the decision by VA to grant presumptive benefits.

"The presumptive law is absolutely essential," he said. "Money should not be an issue."

Sullivan also said many veterans file claims not for the compensation but for access to free health care.

The VA also acknowledged in its heart disease rule Tuesday that it could cost billions more than initially anticipated. The initial projection was that the new ailments, mostly heart disease but also Parkinson's disease and certain types of leukemia, would total $42.2 billion over 10 years. But that was based on disease prevalence rates for the general population, not representative of the aging class of Vietnam veterans.

VA used an age-adjusted formula in its latest proposal and estimated that it could cost some $67 billion in the next decade.

"It's the kind of thing that's just driving us to this $1 trillion, $400 billion deficit this year," Simpson said. "It's not that I'm an uncaring person, but common sense is the most uncommon thing in Washington."

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Scientists expect C-section rate to keep rising

WASHINGTON – More women will be giving birth by C-section for the foreseeable future, government scientists said Monday, releasing a study into the causes of a trend that troubles maternal health experts.

Overall, cesarean deliveries account for about a third of births in the U.S. While much attention has recently focused on women having repeat C-sections, researchers with the National Institutes of Health found that nearly one third of first-time moms delivered by cesarean.

That is "somewhat surprising," said Dr. Jun Zhang, lead author of a study that looked at nearly 230,000 deliveries in 19 hospitals around the country. "It has consequences for future pregnancies."

Many doctors and hospitals follow a policy of "once a cesarean, always a cesarean."

The study also suggested a link between chemically induced labor and higher likelihood of a C-section. Women whose labor was induced were twice as likely to have a cesarean. The authors said more research is needed to clarify if there's a cause-and-effect relationship.

Many medical experts consider cesarean deliveries to be a major component of "overtreatment" in the U.S. — procedures and tests that provide little or no benefit while subjecting patients to additional risks. Indeed, new clinical recommendations say vaginal birth is safe for most women who've had a first C-section.

But the trend does not appear likely to reverse. Since the mid-1990s, the C-section rate in the U.S. has increased by more than 50 percent.

How low should it be? In Scandinavian countries it hovers in the 20 percent range, with no evidence of ill-effects for mothers or babies, Zhang said. How high can it go? In some countries 60 percent to 70 percent of babies are now delivered surgically.

"I hope that we won't get there," said Zhang. "The upward trajectory seems likely to continue in the near future."

Explaining the increase in C-sections is no simple matter. The study found a variety of reasons, some related, including heavier moms and babies, women giving birth later in life, an increase the number of twins and multiple births, and evidence that doctors may be opting for a cesarean if women encounter difficulties in the early stages of labor.

One factor that made no difference was whether the mother had private health insurance or was covered through a government program like Medicaid.

The study was published in the American Journal of Obstetrics & Gynecology.

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