Heart specialists at Johns Hopkins and elsewhere report what is believed to be the first wide-scale evidence linking severe overweight to prolonged inflammation of heart tissue and the subsequent damage leading to failure of the body’s blood-pumping organ.
The latest findings from the Multiethnic Study of Atherosclerosis (MESA), to be published in the May 6 issue of the Journal of the American College of Cardiology, appear to nail down yet one more reason for the estimated 72 million obese American adults to be concerned about their health, say scientists who conducted the research.
“The biological effects of obesity on the heart are quite profound,” says senior study investigator João Lima, M.D. “Even if obese people feel otherwise healthy, there are measurable and early chemical signs of damage to their heart, beyond the well-known implications for diabetes and high blood pressure.”
He adds that there is “now even more reason for them to lose weight, increase their physical activity and improve their eating habits.”
In the latest study, researchers conducted tests and tracked the development of heart failure in an ethnically diverse group of nearly 7,000 men and women, age 45 to 84, who were enrolled in the MESA study, starting in 2000.
Of the 79 who have developed congestive heart failure so far, 35 (44 percent) were physically obese, having a body mass index, or BMI, of 30 or greater. And on average, obese participants were found to have higher blood levels of interleukin 6, C-reactive protein and fibrinogen, key immune system proteins involved in inflammation, than non-obese adults.
A near doubling of average interleukin 6 levels alone accounted for an 84 percent greater risk of developing heart failure in the study population.
The researchers from five universities across the United States also found alarming links between inflammation and the dangerous mix of heart disease risk factors known as the metabolic syndrome. Its combined risk factors for heart disease and diabetes - high blood pressure, elevated blood glucose levels, excess abdominal fat and abnormal cholesterol levels, and particularly obesity - double a person’s chances of developing heart failure.
“More practically, physicians need to monitor their obese patients for early signs of inflammation in the heart and to use this information in determining how aggressively to treat the condition,” says Lima, a professor of medicine and radiology at the Johns Hopkins University School of Medicine and its Heart Institute.
“Our results showed that when the effects of other known disease risk factors - including race, age, sex, diabetes, high blood pressure, smoking, family history and blood cholesterol levels - were statistically removed from the analysis, inflammatory chemicals in the blood of obese participants stood out as key predictors of who got heart failure,” says Lima.
“Both obesity and the inflammatory markers are closely tied to each other and to heart failure,” says lead researcher Hossein Bahrami, M.D., M.P.H.
Each year, nearly 300,000 Americans die from heart failure.
