"Weighty Evidence

Living large can mean dying large, as familiar reminders about obesity's link to cardiovascular disease and diabetes repeatedly emphasize. But those warnings often overshadow another threat from obesity: cancer.

Excess weight accounts for 14 percent of cancer deaths in men, and 20 percent in women, researchers estimate. Among all preventable cancer risk factors, only smoking claims more lives.

Obesity's link to cancer should come as no surprise. Signs of that relationship began to emerge two decades ago. In the late 1980s, laboratory researchers found connections between cancer and insulin—one of the major hormones that responds to obesity.

While the findings got little attention then, today at least a half-dozen companies are developing cancer drugs that interfere with the hormone's cousin—insulinlike growth factor 1 (IGF-1).
"We've been working on this for 20 years," says Derek LeRoith of the Mount Sinai School of Medicine in New York City. Yet until recently, "nobody ever bought into it." After all, even if a tumor does need insulin, the rest of the body does too. The early research was seen as hardly relevant for disease treatment.

Not so today. If clinical trials find that dampening IGF-1 shrinks tumors in cancer patients, scientists will have not only a new kind of cancer drug but also a new source of insight into the interplay between body weight, metabolism, and cancer.

In 2003, a study in the New England Journal of Medicine estimated that if the U.S. population were of a healthier weight, "90,000 deaths due to cancer could be prevented each year." That number may not fall for generations, as obesity rates among even the youngest in the developed world continue to soar. "

This gives us food for thought, and I will continue to reprint this article tomorrow.