TUESDAY, Oct. 8, 2003 (HealthDayNews) -- An estimated one in three Americans born in the year 2000 will develop diabetes at some point in their lives.
If anything, that estimate is a conservative one, says Dr. K.M. Venkat Narayan, lead author of a study detailing those sobering projections that appears in the Oct. 8 issue of the Journal of the American Medical Association.
Even so, the numbers were higher than expected.
"We have all along known that diabetes is common and growing," says Narayan, chief of the diabetes epidemiology section at the U.S. Centers for Disease Control and Prevention. "We knew it [the probability of developing diabetes in a lifetime] would be high, but it was startlingly high even for us."
Adds Dr. Tuan Tran, a fellow in endocrinology at the Ochsner Clinic Foundation in New Orleans, "It's not very surprising, but it is alarming."
One in three people is not the same as one-third of the population because not everyone will develop the disease at the same time. Nor does it mean that people will develop the disease as children; it could be at any point during their lifetime.
Diabetes is a large and growing public health problem. In the last decade, the disease's prevalence has increased 40 percent, from 4.9 percent of the U.S. population to 6.9 percent. Between 2000 and 2050, it is estimated that the number of Americans diagnosed with diabetes will increase by 165 percent. If not adequately controlled, the disease can cause people to lose limbs, eyesight, kidney function and, eventually, their lives.
Despite the severity of the epidemic, no estimates of lifetime risk of developing the disease have ever been published, say the study authors.
Narayan and his colleagues analyzed data on almost 360,000 individuals collected between 1984 and 2000 as part of the National Health Interview Survey. "This is kind of a representative sample of all Americans of all ages, both genders and all ethnic groups," Narayan explains. The researchers used the rates at which diabetes is being diagnosed, as well as death rates, and changes in population structure to make their projections.
They calculated that the estimated lifetime risk of developing diabetes for males born in 2000 is 32.8 percent and for females, 38.5 percent.
Women had a higher lifetime risk at every age.
The highest risk was among Hispanics, with males having an estimated lifetime risk of 45.4 percent and females, 52.5 percent.
People diagnosed with diabetes have shorter life expectancies. The researchers estimate that a man diagnosed at age 40 will lose 11.6 years off his life as well as 18.6 quality-adjusted life-years (QALYs). Women will lose 14.3 actual years and 22 QALYs. Quality-adjusted life-years are calculated by weighting each year with diabetes by 0.75 of a year without diabetes, and are intended to show the quality of life lost due to diabetes.
The upshot is that the risk of developing diabetes is equal to or higher than the risk of developing many other diseases. Compare the diabetes figures with the risk of developing breast cancer (one in eight for U.S. women) and coronary heart disease (one in two for men and one in three for women).
The actual risk may well be higher because the projections assumed that diabetes rates would continue at the same rate. "What we haven't accounted for is if the prevalence actually increased," Narayan says. The researchers also relied only on data on diagnosed diabetes, whereas many cases remain undiagnosed.
The data did not make a distinction between type 1 and type 2 diabetes, but by far the most diabetes cases (about 95 percent) are type 2.
In type 1 diabetes, the body doesn't produce the hormone insulin. This requires people to inject insulin daily to survive and to keep their levels of blood sugar -- called glucose -- under control. If glucose levels get too high, it increases the risk of complications such as blindness or kidney problems.
In type 2 diabetes, the body doesn't make enough insulin or cells don't process the insulin. These people are advised to lose weight, eat a healthy diet and exercise regularly. Some are put on oral medication or insulin to manage blood sugar levels.
The only good news is that information from clinical trials shows that type 2 diabetes may be preventable and, once diagnosed, the progression delayed with lifestyle changes -- such as better nutrition and exercise -- and medications.
"There has been accumulating evidence of the possibility of preventing the disease," Narayan says. "The Diabetes Prevention Program showed that by simple lifestyle modifications you can reduce the rate of progression to diabetes by almost 58 percent. So implementing those results into practice can help us slow down the epidemic."
But is anyone listening? A recent report card on the nation's health from the U.S. Department of Health and Human Services found that almost one in three adult Americans is now obese, double the rate in 1976-1980. Obesity is a major risk factor for diabetes.
Tran reports that when he asks patients if they exercise, they frequently respond that they walk at work or walk to the store from the house. He has to stress that exercise is really something that's separate from your regular daily activities. For some, exercising is a hardship financially and otherwise. "They live in a neighborhood that's unsafe," Tran says. "Not everybody can afford to get a treadmill to exercise in the house."
Still, Narayan thinks there's hope. "The trial of diabetes prevention has been available only during the past one to two years. Hopefully, these things well get implemented," he says. "It will take time to see the results."
Adds Dr. Robert Rizza, vice president of the American Diabetes Association: "There are data that if you treat diabetes, you can substantially reduce risks. If you have the disease and are not managing it, bad things happen."
More information
For more on type 2 diabetes, visit the American Diabetes Association or the National Diabetes Information Clearinghouse.
