Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Brain Reward Area Larger in Video Gamers

An area of the brain associated with addiction is larger than normal in teens who regularly play video games, a new study finds.

But it's not clear if playing video games changes the brain or if preexisting brain differences make teens more likely to play video games, BBC News reported.

The study of 154 14-year-olds found that those who played more than nine hours a week had a larger ventral striatum, the hub of the brain's reward system.

This part of the brain is typically activated "when people anticipate positive environmental effects or experience pleasure such as winning money, good food, sex," said researcher Dr. Simone Kuhn, from Ghent University in Belgium, BBC News reported.

Previous research has also linked this part of the brain to drug addiction.

The study appears in the journal Translational Psychiatry.

-----

Britain Should Ban Smoking in Cars, Medical Group Says

Smoking in cars should be banned, says the British Medical Association.

The influential group released research Wednesday showing that smoking in cars exposes drivers and passengers to 23 times more toxins than smoky bars. Children are especially at risk because their bodies absorb more pollutants, CBS News and the Associated Press reported.

The British government should take the "bold and courageous step" of implementing a ban on smoking in cars, said the BMA's Dr. Vivienne Nathanson.

The U.K. has no law against smoking in private cars. In parts of Australia, Canada and the United States, smoking is banned in cars when children are in the vehicles, BBC News reported.

-----

Drug Slows Prostate Cancer Spread to Bones: Study

A new drug called denosumab delays the spread (metastasis) of prostate cancer to the bones, according to a new study funded by drug maker Amgen.

The study of more than 1,400 patients found that the drug seemed to increase bone-metastasis-free survival by an average of four months, compared to a placebo. But it did not increase overall survival, ABC News reported.

The findings were published in The Lancet.

"Prostate cancer patients who develop bone metastases usually have poor outcomes, so preventing the development of metastasis has been a major unmet clinical need," study author Dr. Matthew Smith, a professor of medicine at Harvard Medical School who serves as a consultant for Amgen, said in a news release, ABC News reported.

Denosumab has U.S. Food and Drug Administration approval for treatment of osteoporosis and prevention of fractures in patients with bone metastases from solid tumors.

-----

Healthier School Lunches Challenged by Congress

Nutritionists and other health experts are outraged that the U.S. Congress is fighting the Obama administration's efforts to make school lunches healthier.

The final version of a spending bill released by Congress Monday would block or delay Department of Agriculture efforts to remove pizza and french fries from school lunches, the Associated Press reported.

For example, the bill would allow tomato paste on a pizza to be considered a vegetable, as it is now. It's expected that the House and Senate will vote on the bill this week and send it to President Obama for signing.

Despite the bill, the USDA says it will continue its efforts to make school lunches healthier.

"While it's unfortunate that some members of Congress continue to put special interests ahead of the health of America's children, USDA remains committed to practical, science-based standards for school meals," spokeswoman Courtney Rowe said in a statement, the AP reported.

"We are outraged that Congress is seriously considering language that would effectively categorize pizza as a vegetable in the school lunch program," Amy Dawson Taggart, director of a group called Mission: Readiness, said in a letter to lawmakers before the final bill was released. "It doesn't take an advanced degree in nutrition to call this a national disgrace."

Mission: Readiness is a group of retired generals who have been advocating for healthier school lunches. They believe poor nutrition in school lunches is a national security issue because obesity is the leading reason for medical disqualification for military service, the AP reported.

-----

Few Baby Boomers Have End-of-Life Legal Documents

A new survey finds that 64 percent of American baby boomers don't have end-of-life legal documents such as a living will or health care proxy.

A living will outlines a person's wishes for medical care if he or she is unable to communicate with doctors. A health care proxy, also called a health care power of attorney, appoints a trusted person to make decisions about medical care if a patient becomes incapacitated, the Associated Press reported.

The AP-LifeGoesStrong.com poll involved online interviews with 1,416 adults, including 1,078 baby boomers -- those born between 1946 and 1964.

One reason why so few baby boomers have end-of-life legal documents is because they feel healthy and young, the AP reported.

-----

Nearly 5 Million More Contact Lenses Recalled by CooperVision

An expanded recall of nearly 5 million contact lenses was announced Tuesday by CooperVision Inc. of California.

Avaira Sphere contact lenses have been added to an August recall of nearly 780,000 Avaira Toric lenses. The products may be contaminated with silicone oil residue and linked to blurred vision, eye injuries and severe pain, msnbc.com reported.

The company produced 6.6 million Avaira Sphere lenses affected by the recall but only 4.9 million were actually shipped to consumers, according to CooperVision spokeswoman Denise Powell.

The recall of the Avaira Sphere and Toric lenses followed a U.S. Food and Drug Administration Class 1 warning, which is the most serious type and is issued when there is a reasonable chance of serious adverse health consequences or death, msnbc.com reported.

For more information, consumers can contact the company at 1-855-526-6737.