Researchers from Johns Hopkins have identified a new risk for obese people: silent heart damage. In a study published in the October edition of the Journal of the American College of Cardiology: Heart Failure, the investigators found evidence that obesity is an "independent driver of heart muscle damage."

Diabetes and high blood pressure are the best-known risk factors for the severely overweight, but in this new federally-funded study, which tracked thousands of middle-age and elderly adults in four states over more than 12 years, researchers discovered obese people who otherwise appear healthy may not be.

One measure of obesity is Body Mass Index, or BMI, a number calculated from a person's height and weight that doctors say is a fairly reliable indicator of body fatness. The Centers for Disease Control and Prevention considers a normal weight status BMI somewhere between 18.5 and 24.9. Overweight is between 25.0 and 29.9 and obese is 30 and above.

Using an ultrasensitive blood test to detect a protein called troponin T, an enzyme released by injured heart muscle cells, the Johns Hopkins researchers measured levels of troponin in more than 9,500 disease-free men and women, aged 53-75. Those whose BMI measured above 35 had more than twice the risk of developing heart failure than people of normal weight.

"Obesity is a well-known 'accomplice' in the development of heart disease," said lead investigator Dr. Chiadi Ndumele in a press release last week," but our findings suggest it may be a solo player that drives heart failure independently of other risk factors."

The severely obese, that is, people with a BMI above 35 were nine times more likely to develop heart failure than those of normal weight, and for every five-unit increase in BMI, the risk increased by 32 percent.

Ndumele went on to say that finding a relationship between obesity  and clinically-undetectable heart damage "is quite potent and truly concerning from a public health standpoint given the growing number of obese people in the United States and worldwide."

Public health experts say heart failure, a condition where the heart muscle is unable to pump efficiently, has been on the rise in recent years and is expected to affect 1 in 5 adults by the year 2030. Coronary artery disease, high blood pressure and diabetes are all common risk factors for heart failure, according to the CDC. Currently, about 5.1 million people in the United States suffer from heart failure. Half of those diagnosed are dead within five years.