Obesity, diabetes are robbing people of sight

4:38PM EST December 11. 2012 – The nation’s twin epidemics of obesity and diabetes are beginning to rob more Americans of their sight, a new study shows.

The percentage of American adults suffering from uncorrectable vision loss spiked 21% in only about six years, rising to nearly 1.7% of the population, according to an analysis of the years 1999-2002 to 2005-08.

Rates of visual impairment doubled among poor people and those who had had diabetes for a decade or more, according to the study, published Tuesday in The Journal of the American Medical Association.Researchers defined impairment as anything worse than 20/40 vision that can’t be corrected with glasses, a problem that disqualifies people from driving in many states.

“This is a dramatic change in eye disease in a small amount of time,” says study author David Friedman, a professor of public health ophthalmology at the Johns Hopkins University School of Medicine.

Typically, this sort of sight loss occurs in old age.

Yet the biggest jump in visual impairment was in adults ages 20 to 39, when these kinds of sight problems are usually rare, says David Musch, an epidemiologist at the University of Michigan Kellogg Eye Center, who wrote an accompanying editorial.

“That made me sit up and take notice,” Musch says. “I would hope this raises a flag for people.”

The total number of Americans with this kind of vision loss is relatively low, at only 1.7% of the population, Friedman says.

But Musch notes that their ranks swelled by nearly 700,000 people in the six-year study period. The number of people with visual impairment is likely to grow, given that rates of diabetes more than doubled in 20 years, from 4.9% of Americans in 1990 to 11.3% in 2010.

Friedman say he’s particularly concerned about children and teens, who are now developing diabetes at younger ages because of being overweight and inactive. The longer people live with diabetes, the greater their chance of suffering serious complications, which can take a decade or more to develop.

“I think of this as a kind of canary in the coal mine,” Friedman says. “It’s the tip of something that is just starting to surface.”

Health officials have warned for years of the dire consequences of obesity, which increases the risk of type 2 diabetes, a condition characterized by high blood sugar levels that can lead to kidney failure, blindness and even amputation.

About 27 million Americans have diabetes, and up to 80 million have “prediabetes,” putting them at high risk of the disease, says Vivian Fonseca, the American Diabetes Association’s president for medicine and science. Fonseca notes that other research has suggested that diabetes-associated vision loss is declining, partly because of better diabetes care.

That research wasn’t as strong as the current study, Friedman says, because it included people whose vision could be corrected with glasses.

Uncontrolled diabetes can damage the tiny blood vessels of the retina, allowing the vessels to leak blood, a condition called diabetic retinopathy, says K. Bailey Freund, a spokesman for the American Academy of Ophthalmology. Leaking blood can cause swelling, detached retinas or other serious problems.

Up to 40% of diabetes patients over age 40 have diabetic retinopathy, according to the study, which drew on data from the Centers for Disease Control and Prevention, which also funded the study.

With proper care and lifestyle changes, however, serious complications are preventable, Friedman says. Research shows that high-risk patients who exercise regularly and lose modest amounts of weight can cut their risk of developing diabetes by more than half.

People with diabetes can reduce their risk of vision loss by keeping their disease under control and undergoing annual eye exams, Fonseca says.

Freund described Friedman’s findings as concerning, but not surprising. Young people diagnosed with diabetes-related eye problems face a lifetime of expensive care, which can include monthly injections of new biological drugs.

In most cases, the eye damage is irreversible, although treatment can prevent further damage, Musch says. “Once you have diabetic retinopathy, it’s really a lifelong disease,” says Freund, a clinical associate professor at New York University School of Medicine. “Unless you make significant improvement in medical control of your disease, it’s likely to get worse.”

The best way to prevent diabetic eye disease, however, is to encourage healthy lifestyles in children, Musch says. “We have to turn the clock back quite a ways, when children are being taught about nutrition,” Musch says.

Yet Irene Sills, a pediatric endocrinologist at Upstate Medical University in Syracuse, N.Y., says doctors like herself are fighting an uphill battle.

Among pediatricians, “obesity prevention is what everybody talks about, every moment of the day,” says Sills, a spokeswoman for the American Academy of Pediatrics. “Changing behavior is one of the hardest things we do. Adolescents aren’t afraid of anything. It’s a difficult time to get people to make significant changes. I can talk about blindness, but when they are out the door, they think, ‘That old lady doesn’t know what she’s talking about.’ “