Posted January 31, 2012

Type 2 diabetes effects on older adults appear minimal

It’s no surprise to hear the term “diabetes epidemic” these days. Diabetes is the leading cause of kidney failure, non-traumatic lower limb amputations and new cases of blindness among adults in the United States. Among U.S. residents aged 65 years and older, 10.9 million, or 26.9 percent, had diabetes in 2010, according to the Centers for Disease Control and Prevention. 

Despite the potential complications, Temple researcher Adam Davey has found centenarians diagnosed with diabetes in their 80s living 20 or more years with the chronic condition.

The study tested 244 older adults, ages 98 to 108, in 44 counties in northern Georgia from the Georgia Centenarian Study. It found that 12.5 percent  —  or 1 in 8  —  of the group had type 2 diabetes, according to Davey and co-authors in the March 2012 issue of the Journal of the American Geriatrics Society.

Diabetes in younger age groups can lead to a number of health problems.  It’s a major cause for heart disease and stroke, vision problems, nerve damage, amputations and mortality, but Davey said he did not find any differences in these factors between individuals with and without diabetes in the group of centenarians. 

“Living 20 years or more after diagnosis is somewhat surprising because although we know that the risk for diabetes increases with age, diabetes is also a risk factor for mortality. This raises the question of how centenarians reach this exceptional age with diabetes,” said Davey, an associate professor of public health in the College of Health Professions and Social Work.

Overall, the risk for death among people with diabetes is about twice that of people of similar age, but without diabetes, according the CDC.

“One potential explanation is that centenarians who are able to reach this age with diabetes are those whose condition is most effectively treated by their health care providers,” he said.

In the study, about one-third of the centenarians with diabetes had been living with it before age 80. About half had been living with it since the ages of 80 to 97, and only 15 percent were diagnosed after age 98. The most common pattern was for these individuals to live with diabetes for many years, but with relatively few disease-related complications.

It is possible that diabetes may have fewer complications when developed later in life. In addition, many older adults suffer from other chronic diseases and it could be difficult to attribute a specific complication to diabetes, Davey said.

“One of the major risk factors from diabetes is cardiovascular disease. In many cases, they probably already have it. How insulin resistance impacts their cardiovascular health also might be different later in life,”  said Duane E. Kirksey, MD, director of the Temple University Institute on Aging and an assistant professor of medicine. “It’s a general trend that more people are developing diabetes because they are overweight or obese.”

Most of the centenarians whose diabetes was being treated took oral hypoglycemic pills, prescription medicines used to control diabetes by lowering the concentration of glucose in the blood. Only a small number used insulin and then at very low dosages.

This finding can be generalized to the Southeast region, which has a higher proportion of African Americans than the nation at large. The study represented 1 in 5 centenarians in the area.

“The study follows what we’re seeing the in the regular population. We’re probably going to see more older people with diabetes,”  said Kirksey.

Kirksey said that he estimates 30 to 40 percent of his patients have diabetes. The majority of his patients, averaging in their late 70s, are African American and overweight.

In our patient population, high blood pressure is a major concern and now diabetes is being added on. It may add more disability in older adults, such as amputation and nerve damage from the effects of diabetes, he said.

Researchers observed some of the same risk factors for diabetes in younger age groups and centenarians in the study. For example, those who were overweight were much more likely to have diabetes. Anemia and hypertension were more common among centenarians who had diabetes. 

African American centenarians are also three times more likely to have diabetes than White centenarians. In an area, such as Philadelphia, with a high proportion of African Americans, we would expect the prevalence of diabetes to be at least as high as found in this Georgia group, Davey said.

The analyses showed that the race difference persisted even when researchers adjusted for differences in factors such as being overweight, suggesting that genetic and lifestyle factors are likely to be important, he added.

It’s also important to note that no one in the group had type 1 diabetes. The distinction between type 1 and type 2 diabetes wasn’t recognized until this group of centenarians was in their 30s.

“We know that the number of centenarians is growing extremely rapidly, and that chronic illness is prevalent among very old adults. So we can expect the prevalence of chronic illness to increase, but what we don’t know is by how much, and with what burden of disease and disease-related complications,” Davey said.

Co-authors in the study are Uday Lele, MBBS, MPH, Department of Public Health, Temple University, Philadelphia, Pennsylvania; Merrill F. Elias, PhD, MPH, Department of Psychology, Graduate School of Biomedical Sciences, University of Maine, Orono, Maine; Gregory A. Dore, BA, Graduate School of Biomedical Sciences, University of Maine, Orono, Maine; Ilene C. Siegler, PhD, MPH, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina; Mary A. Johnson, PhD, Department of Foods and Nutrition, University of Georgia, Athens, Georgia; Dorothy B. Hausman, PhD, Department of Foods and Nutrition, University of Georgia, Athens, Georgia; J. Lisa Tenover, MD, PhD, Geriatric Rehabilitation, Education, and Clinical Center, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California; and Leonard W. Poon, PhD, Institute of Gerontology, University of Georgia, Athens, Georgia. 

— Anna Nguyen