Older adults with type 2 diabetes may be twice as likely as peers without diabetes to develop depression
Older adults with type 2 diabetes may be twice as likely
as peers without diabetes to develop depression, according to an article in the
June 11 issue of Archives of Internal Medicine.
Doctors have known for some time that depression appears to be more common
among patients with the disease, but researchers are still debating the cause-and-effect
relationship. People with diabetes may suffer hormonal imbalances that predispose
them to depression. Depression is associated with physical and behavioral factors
such as obesity and poor diet that may be enough to trigger diabetes in the elderly.
"This is the first study to evaluate diabetes as a risk factor for the
onset of depression in older persons," said study author Matteo Cesari, MD,
PhD, a geriatrician in the University of Florida Institute on Aging. "It's
likely we are looking at a vicious, self-feeding cycle: Diabetes causes depression,
which may reduce adherence to diabetic treatment, therefore worsening the diabetic
condition, and so on."
The researchers evaluated 2,500 healthy patients aged 70 to 79 over a six-year
period to determine if type 2 diabetes is a risk factor for depression. Patients
were enrolled in the Health, Aging and Body Composition study, an ongoing program
sponsored by the National Institute on Aging.
Investigators found that people with diabetes were twice as likely to develop
recurrent depression. The risk was slightly higher for patients did not adhere
to recommended diet and treatment regimens.
About 23 percent of participants had diabetes, and nearly two thirds of those
patients had elevated blood sugar levels. Furthermore, diabetics with high blood
sugar also had elevated levels of the inflammatory marker interleukin-6, which
has been associated with depression.
"There may be a direct biological link between diabetes and depression,"
said Marco Pahor, MD, director of the Institute on Aging. "We know that depression
is linked to proinflammatory cytokines, for one. Diabetes may be one of the triggers
that causes depression."
"Obesity and physical performance are the most important mediators in
the relationship between diabetes and depression reported in the study,"
Cesari said. "It is noteworthy that both are related to poor health status
and poor quality of life."
"The research showing that diabetes has an independent effect on the onset
of new depression is an important finding," said Jack Guralnik, MD, PhD,
chief of the laboratory of epidemiology, demography and biometry at the National
Institute on Aging. "Physicians caring for older diabetic patients need to
be particularly observant to identify the onset of depression so that they can
initiate early treatment."
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