People who develop Type 2 diabetes before age 20 show higher risks of kidney failure and death by middle age than those who develop diabetes later in life, researchers have found.

Type 2 diabetes mellitus is becoming more common in children and teens as obesity rates rise.

Type 2 diabetes can be caused by weight gain, poor nutrition and lack of exercise, which reduces the ability of insulin manufactured by the body to control blood sugar levels.

Dr. Meda Pavkov of the National Institutes of Health in Phoenix, Arizona, and colleagues analyzed data from a 37-year study of Pima Indians, who have disproportionately high rates of diabetes and obesity.

Of the 1,865 participants with Type 2 diabetes, 96 developed it in childhood. All participants had medical exams including blood sugar tests every two years.

For the group developing diabetes in childhood, the natural-cause death rate was nearly double that of those who developed the disease later in life, the team reports in Wednesday's issue of the Journal of the American Medical Association.

The frequency of end-stage kidney disease was also nearly five-fold higher by midlife for those diagnosed with diabetes in youth compared with later in life, the researchers found.

"The longer duration of diabetes mellitus by middle age in individuals diagnosed younger than 20 years largely accounts for these outcomes," the study's authors wrote. 

"Because youth-onset diabetes mellitus leads to substantially increased complication rates and mortality in middle age, efforts should focus on preventing or delaying the onset of diabetes."

Weight-lifting exercise strategy

Another group considered at risk for diabetes are Latinos. According to the U.S. Centers for Disease Control, about half of all Latino children born in 2000 are expected to develop Type 2 diabetes in their lifetime.

Writing in the July issue of the journal Medicine and Science of Sports Exercise, researchers in the U.S. concluded that weight lifting could help overweight Latino teens reduce their risk of diabetes. It was the first controlled study to test the idea in overweight youth.

The study's lead author, Michael Goran, a professor of preventive medicine at the University of California, hypothesized overweight teens would be more likely to stick to a weight program than aerobics, as it was less physically taxing and gave visible results faster.

Overweight Latino teenage boys who lifted weights twice per week for 16 weeks guided by personal trainers showed significantly less insulin resistance compared to a control group, the researchers found.

Insulin resistance is a precursor to diabetes in which the body doesn't respond to the hormone properly and can't process sugars normally.

Although total body fat mass didn't change among weight lifters, their lean muscle mass increased, Goran said.