New calculator predicts newborn's obesity risk

Next time you see an obese adolescent, blame the parents. At least that's what researchers at the Imperial College London are suggesting. They have developed a calculator to predict a newborn's chances of developing childhood or adolescent obesity

With only one in 10 cases of obesity being the result of a rare genetic mutation, researchers set out to determine which environmental factors played the largest roles in the development of childhood obesity.

"Once we compare different statistical models, and we added the genetic variants [associated with causing obesity], their ability to explain childhood obesity didn't improve at all in practice," Marjo-Riita Jarvelin, a pediatrician and one of the study's lead authors, told FoxNews.com. "Genetic variants were not important at a population level to help explain common obesity in a population."

Their simple calculator, available here, considers only a few factors: the parents' body mass indexes (BMIs), the mother's professional status, whether the mother smoked while pregnant, the number of household members, and the child's birth weight.

The team developed this formula after analyzing an ongoing study that has, since 1986, been following more than 4,000 children born in Finland. Jarvelin said they were able to pinpoint the few predictive factors listed above to correctly predict childhood obesity up to 85 percent of the time.

Almost one in five children in the U.S. today is obese, a rate that has tripled since 1980, according to the Centers for Disease Control and Prevention. Jarvelin said that healthy lifestyle habits, including good diets and physical activity, are important in preventing obesity, but whether the mother smokes and is well-educated -- factors that are in play before the child is even born -- also play major roles.

As a hypothetical, two parents with BMIs of 30 (meaning they are obese) can have an 8-pound newborn with a less than 10 percent chance of developing childhood obesity as long as the mother is a professional who does not smoke.

If she smokes, the percentage jumps to almost 16 percent. If she doesn't smoke but is unskilled, it soars to 45 percent. And if she both smokes and is unskilled, the newborn has a 60 percent chance of being obese like his or her parents.

Since most parents can fill out this short survey immediately following birth, Jarvelin argues that seeing the risk their newborn already has could at the very least help them change their own eating and exercise habits, not to mention their child's, to help ensure that he or she does not become obese and develop higher risks of other problems, such as hypertension and type 2 diabetes.

"It's incredible what parents can do," Jarvelin said.