ANN ARBOR, Mich. – More than 16 percent of American Indians and Alaska Natives aged 20 and older have diagnosed diabetes, compared to a national average of seven percent.
That’s the startling information contained in a newly released study from the National Diabetes Education Program (NDEP).
There are several theories about why the effect is so pronounced in the Native American population. “One is the thrifty gene theory,” said Martha Funnell, head of the NDEP program. She chairs the NDEP from the University of Michigan at Ann Arbor.
“People who survived to reproduce many years ago were able to use food very efficiently. There were times of feast and times of famine. One of the things that happened was that people whose bodies used food very efficiently had a better chance of survival.”
Those genetic characteristics have survived. “Today we have lots of feast and not much famine,” Funnell said. “So, perhaps there is a genetic tendency that has an impact.” Being able to use every bite of food effectively could cause overeating, leading to obesity.
“That characteristic was great when people had to store up food, internally, for winter, but we don’t need to do that any more,” she said. Evolution isn’t always our friend.
Research conducted on the Pima Indians for the past 30 years has helped scientists prove that obesity is a major risk factor in the development of diabetes. One-half of adult Pima Indians have diabetes and 95 percent of those with diabetes are overweight.
These studies, carried out with the help of the Pima Indians, have shown that before gaining weight, overweight people have a slower metabolic rate compared to people of the same weight. This slower metabolic rate, combined with a high fat diet and a genetic tendency to retain fat may cause the epidemic overweight seen in the Pima Indians, scientists believe.
Scientists use the “thrifty gene” theory proposed in 1962 by geneticist James Neel to help explain why many Pima Indians are overweight. Neel’s theory is based on the fact that for thousands of years populations who relied on farming, hunting and fishing for food, such as the Pima Indians, experienced alternating periods of feast and famine. Neel said that to adapt to these extreme changes in caloric needs, these people developed a thrifty gene that allowed them to store fat during times of plenty so that they would not starve during times of famine.
This gene was helpful as long as there were periods of famine. But once these populations adopted the typical Western lifestyle, with less physical activity, a high fat diet, and access to a constant supply of calories, this gene began to work against them, continuing to store calories in preparation for famine. Scientists think that the thrifty gene that once protected people from starvation might also contribute to their retaining unhealthy amounts of fat.
The new NDEP study also showed that most people recognize obesity and sedentary habits as diabetes risks - in others, but not themselves.
“What we found was having a family history of diabetes was very strongly associated with believing you are at risk for diabetes,” Funnell said.
“Knowing that they are overweight and more sedentary - people didn’t relate to that as much. They knew that was a risk factor for diabetes, but they didn’t see themselves as at risk.”
A family history of diabetes, however, caught their attention.
Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Diabetes can lead to serious complications and premature death, but people with diabetes can take steps to control the disease and lower the risk of complications.
Some 23.6 million Americans have diabetes. Each year, about 1.6 million people ages 20 or older are diagnosed with diabetes. The number of people diagnosed with diabetes has risen from 1.5 million in 1958 to 17.9 million in 2007, an increase of epidemic proportions. Total health care and related costs for the treatment of diabetes run about $174 billion annually.
Income isn’t necessarily related to diabetes risk, Funnell said, except as it fits with access to safe places to exercise and the availability of fresh fruits and vegetables.
“We did the survey to inform our own programs and projects,” she added. “We have used that information to revise the materials that are on our Web site to get people’s attention.” Their messages now target family history because that gets attention where lack of exercise and excess body weight did not.
“Hopefully by getting people’s attention we can help people to get the screening they need.”
The Indian Health Service has diabetes screening programs available, Funnell said. “Step one is to take a risk test. We have a risk test on our Web site, www.yourdiabetesinfo.org. If that risk test is positive it should be taken to a health care provider for a simple blood sugar test.”
The NDEP survey was done nationwide by telephone, interviewing 2,000 people 35 and older. The NDEP program is jointly sponsored by the National Institute of Health (NIH) and Centers for Disease Control (CDC).