Body roundness a predictor of CVD risk?

A study has found an association between long-term body roundness index (BRI) patterns and an altered risk of cardiovascular disease (CVD), with higher BRI trajectories tied to increased CVD risk.

“Compared with general obesity represented by the BMI, abdominal obesity has been proposed to be a much stronger risk factor for CVD,” said the researchers. Albeit an easier measure for evaluating visceral fat, waist circumference (WC) does not take into account the effect of height, which may lead to under- or overestimation of abdominal obesity in short or tall people. [Eur J Clin Nutr 2010;64:2–5]

“Therefore, researchers have proposed a new body measurement index – the BRI – an abdominal obesity-related anthropometric index … that combines WC and height to describe a person’s body shape and better reflects the proportion of body fat and visceral fat than traditional indices such as BMI, WC, and hip circumference,” the researchers explained.

A total of 9,935 participants (average age 58.85 years, 53 percent men) from CHARLS* with repeated BRI measurements from 2011 to 2016 were included. Participants were divided into three BRI trajectories: low- (49.81 percent), moderate- (42.35 percent), and high-stable (7.84 percent). [J Am Heart Assoc 2024;13:e034768]

From 2017 to 2020, a total of 3,052 CVD events (including 965 stroke and 2,477 cardiac events) and 894 deaths were documented.

Compared with the low-stable group, the moderate- and high-stable groups had higher risks of incident CVD in the crude model (hazard ratios [HRs], 1.61 and 2.63, respectively; p_trend<0.001 for both). These effects remained after adjusting for demographics, medical history, and clinical characteristic variables (p_trend<0.001 for all).

The risk of stroke was also significantly greater among participants with elevated BRI trajectories, as was the risk of cardiac events across all models (p_trend<0.001 for all).

Simultaneously adding the BRI trajectory to the model containing conventional risk factors significantly improved risk reclassification for CVD (cNRI**, 16.35 percent and IDI***, 0.32 percent; p<0.0001 for both), stroke (14.79 percent; p<0.0001 and 0.16 percent; p=0.0004, respectively), and cardiac events (15.64 percent and 0.17 percent; p<0.0001 for both).

“These findings indicate that experiencing a prolonged increase in the BRI would increase CVD risk,” the researchers noted.

The effects may have been driven by the impact of obesity on the myocardium. [Proc Natl Acad Sci U S A 2000;97:1784–1789] “[O]besity may lead to increased production of proinflammatory cytokines, increased oxidative stress, excessive hemodynamic load, and activation of neurohormones, all of which may lead to left ventricular remodeling,” they explained.

A novel indicator of CVD risk

However, the self-reported physician assessments may have introduced information bias, and the results may not be extrapolated to other races or ethnicities as the population was limited to Chinese participants. Nonetheless, the large, diverse sample ensures reliability of the findings.

Moreover, the different BRI trajectories provide a more comprehensive understanding of BRI fluctuations in this cohort. “This approach adds further value to long-term monitoring of the BRI in middle-aged and older adults,” the researchers noted.

The follow-up may have been brief, but this suggests that significant associations between BRI trajectories and CVD risk may be identified in a relatively short period, they added.

“The longitudinal trajectory of the BRI could be used as a novel indicator of CVD risk, which provides a new possibility for CVD prevention … Consequently, future research is necessary to corroborate our findings,” said the researchers.