Waist size predicted heart failure better than BMI - and inflammation explains why

Your scale might say you are a healthy weight. Your waist measurement might tell a different story - and when it comes to heart failure, the tape measure appears to be the better predictor.

Preliminary research presented March 17 at the American Heart Association's EPI|Lifestyle Scientific Sessions 2026 found that measures of abdominal fat - waist circumference and waist-to-height ratio - were more strongly associated with heart failure risk than body mass index (BMI) in a study of nearly 2,000 African American adults. More intriguingly, the study identified a biological mechanism linking belly fat to heart damage: chronic inflammation accounted for roughly one-quarter to one-third of the connection.

The belly fat distinction

The study drew on data from the Jackson Heart Study, which enrolled 1,998 African American adults ages 35 to 84 in three counties in urban and rural Jackson, Mississippi, between 2000 and 2004. None had heart failure at enrollment. The participants were followed for a median of 6.9 years, during which 112 developed heart failure.

The researchers, led by Szu-Han Chen, a medical student at National Yang Ming Chiao Tung University in Taiwan, measured body fat using multiple methods: weight, BMI, waist circumference, and waist-to-height ratio. They also tested blood samples for high-sensitivity C-reactive protein (hsCRP), a widely used marker of systemic inflammation.

The central finding: elevated waist measurements were associated with increased heart failure risk, while high BMI alone was not. People with larger waist circumferences and higher waist-to-height ratios were significantly more likely to develop heart failure, even when their BMI fell within ranges typically considered normal.

Where fat sits matters more than how much there is

This result aligns with a growing body of evidence that visceral fat - the fat deposited around internal organs in the abdominal cavity - is metabolically distinct from subcutaneous fat elsewhere on the body. Visceral fat is more hormonally active, produces more inflammatory cytokines, and has stronger associations with metabolic disease than fat stored under the skin of the arms, legs, or hips.

BMI, which divides weight by height squared, cannot distinguish between these fat types. A person with substantial visceral fat but relatively lean limbs might have a "normal" BMI while carrying the kind of fat most strongly linked to cardiovascular damage. Waist circumference, while imperfect, captures visceral fat distribution more directly.

Inflammation as the connecting thread

The study's most mechanistically interesting finding was the role of inflammation. Higher levels of hsCRP - indicating greater systemic inflammation - were independently associated with heart failure risk. When the researchers performed mediation analysis, they found that inflammation accounted for approximately 25% to 33% of the statistical link between abdominal fat measures and heart failure.

This suggests a potential pathway: visceral fat produces inflammatory signals, chronic inflammation damages blood vessels and heart tissue, and heart failure eventually results. If that causal chain holds, it opens a therapeutic question - could reducing inflammation in people with central obesity lower their heart failure risk, even without weight loss?

"By monitoring waist size and inflammation, clinicians may be able to identify people with higher risk earlier and focus on prevention strategies that could reduce the chance of heart failure before symptoms begin," Chen said.

Important limitations

This is a conference abstract, not a peer-reviewed publication, and should be treated as preliminary. The study population was exclusively African American adults from the Jackson, Mississippi area, which limits generalizability to other racial or ethnic groups. With 112 heart failure events among 1,998 participants, the statistical power for subgroup analyses is limited.

The researchers did not have data on heart failure subtypes - a significant limitation since heart failure with preserved ejection fraction and heart failure with reduced ejection fraction have different risk profiles and may relate differently to obesity and inflammation. The follow-up period of 6.9 years, while substantial, may not capture the full long-term effects of abdominal obesity on heart failure development.

The mediation analysis establishes a statistical relationship between belly fat, inflammation, and heart failure, but it cannot prove causation. Whether reducing inflammation directly prevents heart failure in this population would require an interventional trial.

Still, the practical message is straightforward: measuring waist circumference in routine clinical visits may identify heart failure risk that BMI misses entirely. A tape measure costs less than a blood test, and the information it provides about visceral fat distribution appears to be clinically meaningful.