Insulin resistance may raise the risk of heart failure in elderly men, new research shows.

The study, done in Sweden, is published in The Journal of the American Medical Association.

Before exploring the findings, take a minute to learn about insulin resistance and heart failure.

Insulin Resistance

Insulin is a hormone made by the body to control blood sugar.

In people with insulin resistance, the body's response to insulin falters. Normal amounts of insulin won't do. Instead, it takes more and more insulin to get the job done.

Insulin resistance often later leads to type 2 diabetes. It's also seen in metabolic syndrome, a cluster of abnormalities that increases the risk of developing heart disease and diabetes. These include obesity, abnormal blood fats, high blood pressure, and elevated blood sugar.

Read WebMD's "Get the Facts About Heart Failure"

About Heart Failure

In heart failure, the heart doesn't quit. It becomes less effective.

The heart muscle doesn't pump as much blood as the body needs. The heart may become enlarged and weakened, which reduces the amount of blood pumped out to the body. Many things can cause heart failure including high blood pressure, past heart attacks, or coronary artery disease (clogged arteries on the heart muscle).

Read WebMD's "'Risky' Diabetes Drug May Help Heart Failure"

Heart Failure's Dangers

Running the body on a weaker heart can take its toll, write the researchers.

They included Erik Ingelsson, MD, of the public health and caring sciences departments at Sweden's Uppsala University.

The death rate for heart failure patients is four to eight times that of the general public, even after adjusting for age, write Ingelsson and colleagues.

Heart failure is also a major source of illness.

Read WebMD's "Eating Fish May Help Avoid Heart Failure"

Warning Signs

Heart failure's main causes are high blood pressure and coronary artery disease.

Other things that may increase the risk of developing heart failure include smoking, obesity, high blood fat levels, diabetes, valve-related heart disease, and a thicker-than-normal left ventricle in the heart, write the researchers.

Their study suggests that insulin resistance may belong on that list.

Read WebMD's "5 Steps to a Healthier Heart"

Study's Findings

Ingelsson's team studied more than 1,100 older men for about nine years, on average.

When the study started, the men were all at least 70 years old. They didn't have heart failure at the time.

During the study, 104 men developed heart failure.

Insulin resistance was a risk factor for heart failure, write the researchers. Taking other known risk factors into account didn't change that.

Insulin resistance could partly explain the link between obesity and heart failure, they write.

The study only included elderly men living in Sweden. It's not known if the findings apply to other people, write the researchers.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Ingelsson, E. The Journal of the American Medical Association, July 20. 2005; vol 294: pp 334-341. WebMD Medical Reference from Healthwise: "Heart Failure: Topic Overview." News release, JAMA/Archives.