Holiday gatherings, football playoff parties, and bundling up to stay warm bring plenty of joy to the season. The festivities can also come with a common and dangerous side effect: the “beer belly.”

New research sheds light on how this visceral obesity can result in cardiac damage in different ways from general obesity measured by BMI — an important consideration for clinicians, study authors said. This observation was more pronounced in men than in women, according to the research, recently presented at the Radiological Society of North America annual meeting.

“While an increase in BMI was associated with ‘a larger heart’ in simple terms, visceral obesity was associated with concentric remodeling,” study co-author Jennifer Erley, MD, said in an interview with Medscape Medical News.

Despite the high prevalence of obesity in the industrialized world, it is still unknown whether obesity has independent effects on cardiac remodeling, said Erley, a radiology resident at the University Medical Center Hamburg-Eppendorf in Hamburg, Germany.

“We know from many body composition studies nowadays that visceral fat has totally different effects on other organ functions than subcutaneous fat,” Erley said. “That is why we took a look into investigating the effect of general and also visceral obesity on cardiac morphology and function in this German-based population study.”

Examining Obesity’s Effects

The study included 2173 patients (43% female; mean age, 64 years) aged 45-74 years from the population-based prospective Hamburg City Health cohort study. The researchers performed 3T cardiovascular MRI and excluded patients with known cardiac diseases.

Patients had a median waist-to-hip ratio, used to measure visceral fat, of 0.94 and a median BMI of 26.3. Based on waist-to-hip ratio, the researchers deemed 80% of patients obese (waist-to-hip ratio, ≥ 0.85 in women and ≥ 0.90 in men) compared with 20% who they considered obese according to BMI ≥ 30.

Data showed that a 0.1 increase in the waist-to-hip ratio led to a 3.9-g rise in left ventricular (LV) end-diastolic mass. This same rise in waist-to-hip ratio was also associated with drops of 4.4 mL in LV end-diastolic volume and 5.7 mL in right ventricular (RV) end-diastolic volume (P < .001 for both), as well as significant decreases in end-systolic volumes, which led to a significant decrease in stroke volumes (LV, -2.2 mL; P < .001; RV, -2.1 mL; P = .002).

Furthermore, the researchers found that with every 0.1 increase in the waist-to-hip ratio, RV end-diastolic volume decreased by 4.5 mL (P = .024) and RV stroke volume decreased by 2.9 mL (P = .033), an association weaker in women than in men.

Moreover, a 1-point increase in BMI yielded a 2.3-g rise in LV end-diastolic mass (P < .001), a 0.5-mL increase in LV end-diastolic volume (P = .002), and a 0.4-mL higher LV stroke volume (P < .001), whereas RV structure and function was not significantly linked to BMI. The increase in LV end-diastolic mass for women was -0.9 mg weaker for every one point added to BMI (P < .001).

Possible Mechanisms

“The results provide evidence for the so-called ‘clinical eye’ and how we use data in our daily clinical routine,” said Sebastian Kelle, MD, PhD, head of the Cardiac Imaging Unit at Deutsches Herzzentrum der Charité in Berlin, Germany, who was not involved in the study.

Kelle told Medscape Medical News that the first of the two main takeaways from the data is that BMI and the waist-to-hip ratio affect the heart differently. He said this difference is potentially explained by general obesity increasing blood volume and cardiac workload and promoting chamber dilation and visceral fat driving metabolic and inflammatory stress that favors hypertrophy without dilation.

“The second main finding is sex matters,” Kelle said. “Associations are stronger in men — potentially hormonal, metabolic, and fat-distribution differences likely modulate cardiac responses to both general and visceral adiposity.”

High Waist-to-Hip Ratio: ‘More Dangerous’ to the Heart

The study’s results are relevant to both patients and specialists performing cardiac imaging, Erley said.

“Patients should be aware that a high waist-to-hip ratio appears ‘more dangerous’ than a high BMI regarding potential effects on the heart,” she said. “Medical specialists should take into account the waist-to-hip ratio and not only BMI when assessing a patient’s nutritional status. Imaging specialists should be aware that concentric remodeling patterns in cardiac MRI might be attributed to visceral obesity (we currently primarily think of other diseases like hypertensive heart disease).”

Kelle agreed that measuring the waist-to-hip ratio will be important going forward. Visceral obesity metrics should always be part of cardiovascular risk assessment because visceral adiposity is metabolically active and strongly linked to cardiometabolic risk, he said.

“Relying solely on BMI may miss individuals at risk for concentric cardiac remodeling,” he said. “In addition, cardiac evaluation of obesity should be sex-specific. The recent data underscore that using the same thresholds for both sexes may over- or underestimate cardiac risk.”

Erley and Kelle reported having no relevant financial relationships.

Brian Ellis is a freelance writer and editor who lives in Southwest Virginia.