Oct. 15 2001 -- Like parents everywhere, Diane Martin, of Lafayette, Ind., thought there were better things for her 13-year-old son David to be doing this past summer than hanging around the house watching television and bickering with his sister.
So she enrolled David in a summer camp at nearby Purdue University. Basketball, swimming, soccer, and the company of 45 other boys -- that was the ticket for a healthy summer.
But that wasn't all there was to Camp Calcium, a project of researchers at Purdue to study the relationship between calcium intake and growth of bones in a natural, and fun, setting. The boys were also taught some important lessons about osteoporosis, a disease that occurs when bones become brittle and susceptible to fracture.
For six weeks, David and the other boys consumed a controlled diet of varying amounts of calcium and received periodic bone scans. They were also required to collect their feces and urine so researchers could determine how much calcium was being retained in their bones, and how much was being excreted.
In the normal course of things, collecting urine and feces might not be considered summertime activity for 13-year olds -- but anything can be made to seem routine after a while. "David didn't mind the collections," his mother says. "All the boys were doing the same thing, so it was just normal."
In return, David was paid seven dollars a day for participating, and enjoyed all the activities typical of summer camp. He lived in a dorm with the other guys and attended minicamps in soccer, basketball, swimming, track, and bowling, receiving instruction from Purdue University coaches.
"We wanted to expose these kids to activities they would be doing normally in their life," says Berdine Martin, PhD, lead researcher in the Camp Calcium study. "It's a way to get kids to participate in a study that is enjoyable and has an educational feature."
Not For Women Only
That education may save David's bones later in life. "He understands the importance of calcium and how it will affect him in the future," his mother tells WebMD.
It's a lesson not widely known to apply to young boys. But Connie Weaver, PhD, head of the department of foods and nutrition at Purdue, says the notion that osteoporosis is only an elderly woman's concern is a myth.
And because the bones that kids build as teens will be the bones that last -- or fracture -- in their older years, it's wise to start early, Martin says.
"It's important to consume a diet that will maximize your genetic potential for the heaviest bones possible," she tells WebMD. "Men and women will lose some bone as they age. If we start at a higher point as teens, then obviously we can postpone and prevent factures."
As Weaver puts it: "You get more bang for your buck if you build a strong skeleton when you are young."
Camp Calcium is now in its seventh year, though this past summer was the first time the camp was run for boys. Funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMSD), the camp has sought to answer these fundamental questions: How does the body use calcium to build strong bones? And how much calcium should young people have in their diet?
At this year's camp, researchers sought to determine the level of calcium intake that would result in the optimum amount being retained by the boys' bones. The boys were fed controlled diets that included from 1,800-2,200 milligrams of calcium (approximately six or seven glasses of milk) a day.
By analyzing the urine and feces collections, researchers will be able to determine how much calcium is being excreted -- as opposed to absorbed by bones -- at varying levels of dietary intake. Results from the research will be published early next year.
"We want to see how absorption and retention of calcium reacts to changes in intake," Martin explains. "Is there a point of diminishing returns at which drinking more milk is not going to do any good?"
For kids like David Martin, Camp Calcium is a fun and unusual way to spend a summer. But the findings from research at the camp will likely affect their lives, and their bones, decades from now.
On the basis of results from Camp Calcium's earlier research with girls, the National Academy of Sciences' Institute of Medicine revised its recommendations for the amount of calcium girls should consume from 1,200 milligrams a day to 1,300 milligrams (approximately four to five glasses of milk).
"We have a serious goal of trying to understand the metabolism of calcium during the adolescent growth spurt," says Joan McGowan, PhD, chief of the musculoskeletal disease branch at NIAMSD. "Osteoporosis is not going to be a factor in these kids' lives for half a century, but among those who do get it, probably 50% will have had inadequate bone acquisition in adolescence."
McGowan says that when it comes to building bones, it's adolescence or never. "It's not possible to really build the skeleton after adolescence, so it's critical to put as much bone in the bank as you can," she says.
She calls the camp an innovative way to attract kids to participate in a research project -- always a challenge when the more typical setting is a hospital or clinic with white-coated researchers. And previous camps for girls have had the added benefit of introducing young women to science and to women scientists, she says.
"The girls were exposed to excellent role models for careers in science in a very positive setting," she says.
As for David Martin, he did his part for science this summer. Will he come back next year? "Maybe," his mother reports him saying.
That sounds like a reasonable response from a 13-year old, for whom next summer is a lifetime away. In the meantime, he is grateful for his experience at Camp Calcium and is smiling all the way to the bank.
"He made pretty good money, which made him happy," says Diane Martin. "Now he has a savings account."