Earlier diabetes diagnosis linked to worse mid-life heart health

April 29, 2012: In this file photo a woman diagnosed with diabetes gives herself an injection of insulin at her home in the Los Angeles suburb of Commerce, Calif. (AP)

When people develop diabetes early in life they may also be more likely to experience heart problems in middle age, a study suggests.

Cardiovascular disease has long been linked to diabetes in older adults. The new study, however, offers fresh evidence that getting diabetes as a younger adult may exacerbate or accelerate the erosion of heart function as people age.

"Diabetes is toxic to the heart since it affects many important components of the machinery," said Dr. Genevieve Derumeaux, a researcher at Henri Mondor Hospital in Creteil, France and author of an editorial accompanying the study.

In particular, diabetes can damage the left ventricle, the bottom left chamber of the heart responsible for pushing oxygen-rich blood out into the circulatory system, Derumeaux said by email. Over time, diabetes can make it harder for the chamber to fill with blood and pump blood out into the body.

Globally, about one in 10 adults have diabetes, according to the World Health Organization. Most have type 2 diabetes, which is associated with obesity and aging and occurs when the body can't make or process enough of the hormone insulin.

Medications as well as lifestyle changes such as improved diet and exercise habits can help manage diabetes and keep symptoms in check. When diabetes isn't well managed, however, dangerous spikes in blood sugar can eventually lead to blindness, amputations, kidney failure, heart disease and stroke.

For the current study, researchers examined data on nearly 3,200 adults over a 25-year period starting in 1985 when they were between 18 and 30 years old.

After initial medical exams, participants received a series of seven additional checkups during the study period. The exams included assessments of blood sugar and the ability to process the hormone insulin, as well as imaging tests known as echocardiograms to determine heart health.

By the end of the study, the participants who lived the most years with diabetes were much more likely to have heart damage than their peers without diabetes or participants who only developed the condition more recently, the study found.

When people developed what's known as insulin resistance, a failure to process the hormone, they were also much more likely to experience heart damage by the end of the study.

One limitation of the study is that researchers lacked data on diabetic complications, making it impossible for them to assess how specific problems that developed with this disease might influence the odds of heart damage, the authors note in the Journal of the American College of Cardiology.

Even so, the findings point to the importance of preventing the onset of diabetes and controlling blood sugar properly if the condition does develop, the authors conclude.

"Cumulative exposure to diabetes and higher insulin resistance from early adulthood to middle age are risk factors for adverse cardiac dysfunction later in life," lead study author Dr. Satoru Kishi, a diabetes researcher at Mitsui Memorial Hospital in Tokyo, said by email.