WEDNESDAY, Feb. 3 (HealthDay News) -- Adding more evidence to theories linking DNA to weight, European scientists report that a genetic variation seems to virtually guarantee that a person will become obese.

The genetic variation in question robs people of about 30 genes and appears to be found in seven of every 1,000 severely obese people, the researchers report. The same variation also may be linked to mental retardation and learning disabilities.

"Obesity is definitively a genetic trait, and it is very likely that additional small chromosomal abnormalities exist that may dramatically increase the risk of obesity and may also be linked to brain developmental problems," said Dr. Philippe Froguel, co-author of a study published in the Feb. 4 issue of the journal Nature and head of genomic medicine at Imperial College London.

In the new study, researchers examined the genes of teens and adults who had learning difficulties and developmental delays. Thirty-one people were missing the genes in question, and all were obese.

The researchers then looked at the genomes of 16,053 people who were either of normal weight or obese. Nineteen people had the same genetic deletion, and all were severely obese.

"We feel that this is a major advance -- the first paper to convincingly demonstrate that a relatively rare genetic variant can also be an important cause of common obesity," said study co-author Alexandra Blakemore, a senior lecturer at Imperial College London.

"Although the percentage of severely obese people with this (variation) is just under one person, that adds up to an awful lot of people in total," Blakemore said. "The effect on carriers is very strong."

But what are the missing genes doing to the body to make people become obese? That remains to be determined.

"The mechanism by which this genetic defect unveils itself may give us insight into how other conditions lead to obesity. There may be an enzyme or a protein that is involved in the development of obesity," said Dr. Stuart Weiss, an assistant clinical professor at NYU Langone Medical Center, who is familiar with the study findings.

Finding the cause "will allow us to investigate medications and therapies" that could turn something in the body on or off, he said.

Not all obese people can get skinnier by eating less and exercising more, Weiss said. "The bottom line is that they may be able to eat less, but their bodies may be so efficient that they can extract calories from food much more effectively and may not be burning energy as efficiently as others," he said.

This fact leads to unhappy news for some obese people, he said. "If you're eating just one pea and you're gaining weight, you'll have to cut the pea in half."

Still, the future could bring genetic tests for patients that could allow doctors to tailor treatments to their particular bodies, he added.

More information

The U.S. National Institutes of Health has more on obesity.

WEDNESDAY, Feb. 3 (HealthDay News) -- Following the introduction of Wii to video gaming in 2006, more than just the ligaments and tendons in the hands of players are getting injured these days: a new report details foot injuries that have been incurred while playing with the Wii.

"Before these types of games were introduced, patients typically presented with ligament injuries of the hand from intensive use of [video game] hand-held controls," noted Karen A. Eley. A plastic surgery resident and doctoral candidate at Oxford Radcliffe Hospitals NHS Trust in Great Britain, she outlined the specific nature of what is now known as "Wiiitis" in a letter in the Feb. 4 issue of the New England Journal of Medicine.

"Now, the injuries seem to affect any region of the body," Eley added.

In her commentary, Eley said that the so-called "Nintendinitis" of the 1990s -- involving thumb tendon pain -- has given way to an increasing number of foot-related injuries in conjunction with the rise of the popularity of the Wii.

Such injuries can result, for example, when otherwise healthy players fall off special pressure-sensitive "balance boards" that are raised two inches off the ground and are designed to read the body movements of gamers without the need for hand controls.

This type of fall has been seen to result in soft-tissue swelling, dislocations, muscle pulls and even small fractures -- as highlighted by Eley in recounting the case of a 14-year-old girl who sought emergency medical care for such injuries at a British hospital.

Head injuries are another aspect of Wiiitis, Eley pointed out, resulting from the grouping of gamers in confined spaces, prompting unintentional bumping and striking.

Her observations notwithstanding, Eley said that Wiiitis injuries are not yet a frequent hazard of gaming.

"I have not encountered many injuries of this nature," she stressed. "I think that in some respects some people are just rather unlucky. I am sure that many more people twist their ankles when they miss their footing on the Wii-fit balance boards, but the injury is not significant enough to seek medical treatment. We only see the ones that are particularly severe."

And on a more positive note, Eley added that Wii does, in fact, encourage people who might otherwise be sedentary to get up and move.

"And as with any activity, it is this group that are more likely to sustain strains and sprains," she said. "[But] hopefully, playing these games will result in people becoming interested in participating in exercise, aiding in our fight against obesity, heart disease and diabetes."

Robert Gotlin, director of the Sports Rehabilitation department at Beth Israel Medical Center in New York City, concurred with Eley's sense that while the risk for injury due to Wii gaming is real, it is not a cause for alarm.

"Any physical activity or recreational fad always brings with it the risk of newfound injuries. We've seen this across the board, ranging from the so-called 'BlackBerry thumb' to Nintendo wrist injuries," Gotlin observed.

"And even though everything carries some risk -- from jumping off a couch to stepping off a curb -- in this case Wii largely involves kids, so we should try to make sure they are safe," Gotlin noted. "That means -- like any activity -- it should not be overdone. And it should be part of a kid's life, not their whole life. And it should come with some parental guidance."

He added, "But then the question is whether kids -- who at the age of 7, 8 or 9 are just becoming masters of their own neuromuscular control -- get a benefit learning about balance and movement through Wii games that outweighs their risk for injury? Well, I would say that it certainly beats being sedentary and sitting on the couch. And the reality is that problems seem to happen to just a few kids, and the risk-benefit is very low. So I would not go overboard with concern."

More information

For more on fitness and stretching exercises, visit the U.S. Department of Health and Human Services.

WEDNESDAY, Jan. 20 (HealthDay News) -- Slashing salt intake by just 3 grams a day -- the equivalent of half a teaspoon -- could dramatically cut the incidence of heart disease and death in U.S. adults, researchers claim.

According to the authors of a study in the Jan. 20 online edition of the New England Journal of Medicine, the projected reductions would be similar to the benefits accruing from a 50 percent drop in the smoking rate and a 5 percent decline in body mass index among obese adults.

"There's no question that Americans eat too much salt," said Dr. Robert Eckel, a professor of medicine at the University of Colorado Denver School of Medicine. "The idea of salt restriction and reducing blood pressure-related outcomes such as heart disease and stroke has been under consideration for some time. This group just simply took a map to it. The study certainly has scientific validity in terms of the importance of salt reduction for quality of life and longevity."

"Is everyone going to make the same change? Maybe not," said Karen Congro, director of the Wellness for Life Program at Brooklyn Hospital Center in New York City. "But even a small change would reduce the total number of strokes and heart attacks over time because the situation is so dire. It would also be beneficial to immediate health."

U.S. health agencies recommend that most adults limit their daily consumption of salt to less than 5.8 grams (2,300 milligrams [mg] of sodium), with 3.7 grams a day preferable.

The American Heart Association urges the average American to eat less than 2,300 mg of sodium daily, but also notes that older people, blacks and people with high blood pressure need to go even lower -- to under 1,500 mg per day.

Despite these recommendations, the average daily intake of salt is on the increase.

In 2005-2006, the study authors stated, men in the United States took in an average of 10.4 grams of salt a day and women consumed 7.3 grams a day, far more than the suggested limit.

Excess salt can cause or worsen high blood pressure and raises the risk for cardiovascular disease.

This is not the first time Americans' favorite dietary supplement has hit the news in recent days.

The New York City Health Department, under Mayor Michael Bloomberg, has announced that it is spearheading the "National Salt Reduction Initiative," which aims for a 20 percent reduction in salt consumption over five years.

The initiative is targeted primarily at restaurants and food manufacturers, which supply the gross majority of sodium in American diets.

Only about one-quarter of the salt in the U.S. diet comes directly from the kitchen table salt shaker.

The researchers, from the University of California, San Francisco, fed previously published data on heart disease in U.S. adults aged 35 to 84 into a computer model.

The model then predicted that the reduction of 3 grams of salt a day would cut the number of new cases of coronary heart disease each year by 60,000 to 120,000; stroke by 32,000 to 66,000 cases; and heart attacks by 54,000 to 99,000.

The annual number of deaths from any cause would be reduced by 44,000 to 92,000.

Limiting salt intake would be good for the fiscal diet as well, saving an estimated $10 billion to $24 billion in health care costs yearly, the paper found.

But if Americans cut even a mere 1 gram of salt from their meals and snacks every day, the effects would still be stunning, the authors stated: 20,000 to 40,000 fewer cases of coronary heart disease; 18,000 to 35,000 fewer heart attacks; 11,000 to 23,000 fewer strokes; and 15,000 to 32,000 fewer deaths.

Given that so much sodium comes from processed food, the authors urged a public health initiative to curb consumption.

More information

The American Heart Association   has more on shaking your salt habit.

THURSDAY, Jan. 7 (HealthDay News) -- If you're vowing to lose weight this year, consider adding a regular exercise program while you're cutting calories.

Combining the two results in better health outcomes -- such as lower blood pressure and cholesterol levels -- than simply cutting calories alone, a new study finds.

"It's better to lose weight with a combination of caloric reduction and exercise rather than caloric reduction alone," said study author Dr. Enette Larson-Meyer, an assistant professor of family and consumer science at the University of Wyoming.

For the six-month study, the researchers assigned 36 overweight men and women, average age 39, to one of three groups. One group cut calories by 25 percent. The second cut calories by about 12.5 percent and exercised enough to increase energy output by 12.5 percent. A control group simply stayed on a weight-maintenance diet.

At the study's end, both the caloric-restriction group and the caloric-restriction plus exercise group lost about 10 percent of their body weight. The average weight at the study start was about 178 pounds, so the loss at the end was about 17 pounds on average.

The exercise prescription varied according to body weight at the start, but typically men walked for 50 minutes at a brisk pace five days a week, and women, 45 minutes five times a week, Larson-Meyer said. They could choose their preferred activity and intensity, however.

At the end, those who included exercise had better health outcomes, according to the study published in the January issue of the journal Medicine & Science in Sports & Exercise.

"The big improvement was related to blood pressure," Larson-Meyer said. The exercising and dieting group had greater blood pressure improvements, and improvement in cholesterol and insulin sensitivity, too, she said.

"It's not surprising at all," Larson-Meyer added. "They definitely work together."

Working with a professional to decide on calorie restriction and workout routine is best, she noted, especially for obese people with orthopedic problems.

The results make sense to Dr. Walt Thompson, a professor of kinesiology at Georgia State University who has studied exercise adherence for years. "I think it finally proves what we have been saying for a long time," he said. "Effective weight-loss programs have to include diet and exercise."

While it's not difficult for people to start an exercise program -- many people do so every January 1st, he noted -- sticking with it is hard for most. "By January 15, 50 percent are going to drop out," he predicted.

His tips for getting people to stay faithful? Identify what is important to you -- long-term goals. That might be weight loss. Then come up with short-term exercise goals to help you get to the long-term goal.

Hiring a wellness coach might help, too, he noted. They are experts in helping people change their behaviors.

Overcoming obstacles is important, Thompson said, and lack of time is a big one. When he hears that excuse, he asks people how much TV they watch. Two hours a day is the typical answer.

His suggestion: Record the programs to watch later, skip the commercials, and you've found your exercise time.

He tells potential exercisers to find something that motivates them. "Two things motivate me," said Thompson. "My dad had a heart attack at 52, and I was bound and determined not to."

His other motivation? About 32 years ago, before he married his wife, she said to him: "If you get fat, I will divorce you."

He's pretty sure she wasn't kidding. And now, it matters little. He remembers her saying it as if it were yesterday, and it still motivates him.

More information

To learn more about how to start an exercise program, visit the American Council on Exercise  .