Study: Lack Of Sunlight, Milk, Exercise Causing Bone Deficiency In Children

Rickets is making a comeback, but bone specialists are more concerned that the recent rise in diagnosis of the disease (virtually wiped out until the 1990s) is a red flag indicating another, more serious issue — that possibly millions of seemingly healthy children aren’t building as much strong bone as they should, which may leave them more vulnerable to osteoporosis in the future than their grandparents are now.

Experts say that an overall lack of milk, sunshine and exercise is becoming an anti-bone trifecta. As a result, scientists are taking the first steps to ascertain how much of a problem is caused by kids not getting enough of the bone-building trio, based on new research that shows what “normal” bone density is for children of different ages.

Dr. Heidi Kalkwarf of the Cincinnati Children's Hospital led a national study that gave bone scans to 1,500 healthy children ages 6 to 17 to see how bone mass is accumulated. This resulted in the first bone-growth guide for children — similar to height-and-weight charts — being published last summer, designed specifically for pediatricians treating children at high risk of bone problems.

The government-funded study will continue to track those 1,500 children for seven more years to see how their bones turn out. Ultimately, the study seeks to find exactly what bone-growth level is cause for concern.

“I don't know if we're raising a population that's going to be at risk for osteoporosis,” Kalkwarf says. “It's really hard to know what the cutoff is; how low is too low?”

Since almost half of peak bone mass develops during adolescence, the concern is that missing out on the strongest possible bones in childhood could haunt people decades later. By the 30s, bone is broken down faster than it's rebuilt. Then it's a race to maintain bone and avoid the thin bones of osteoporosis in old age.

“There's some early data showing that even a 10-percent deficit in your bone mass when you finish your adolescent years can increase your potential risk of having osteoporosis and fractures by as much as 50 percent,” says James Beaty, Ph.D., president of the American Academy of Orthopaedic Surgeons.

Already there's evidence that children in the United States break their arms more often today than four decades ago — girls suffer breaks 56 percent more often, while boys suffer breaks 32 percent more often, according to a Mayo Clinic study. Some say this is due to newer forms of risky play — like inline skates — but Kalkwarf's hospital recently found that kids who break an arm have lower bone density than their playmates who don't.

Doctors have long known that less than a quarter of adolescents get enough calcium, but strong bones require more than calcium alone. Exercise is at least as important. (Consider this: The dominant arm of a tennis player has 35-percent more bone than the non-dominant arm.)

Likewise, the body can't absorb calcium and harden bones without vitamin D, which is absorbed by the body following exposure to sunlight. But by some estimates, 30 percent of teens get too little of the “sunshine vitamin”. This is suspected to be the result of increased teen computer use, a lack of safe places to play outdoors and less school physical education keeping kids and adolescents inside and away from the sun. In addition, because skin pigment alters a person’s rate of sun absorption, black children are particularly at risk.

Rickets marks the worst deficiency, where bones become so soft that legs literally bow. Rickets was once thought to have been eradicated with milk fortification, but the comeback of the disease suggests that there is more to solving the problem.

“I am now treating rickets in a way that I never treated it 20 years ago,” says Laura Tosi, Ph.D., bone health chief at Children's National Medical Center in Washington.

She diagnoses rickets or super-low D levels in children every month at a bone clinic she runs for mostly inner-city children. Fortunately, rickets caught early is easily cured with high-dose infusions of vitamin D and calcium. However, Tosi says it’s the kids whose vitamin D levels haven’t gotten quite low enough to produce symptoms of deficiency that she worries about, because they may never get treated.

Source: http://www.lookingfit.com/hotnews/7bh279755.html