A large Chinese study of over 4 million adults found that BMI alone is insufficient for assessing the risk of chronic diseases like COPD, cardiovascular disease, and diabetes, and that alternative measures focusing on body shape, central fat distribution, and visceral adiposity better predict disease risk across different conditions.
- BMI showed weaker and more complex relationships with COPD and cancer compared to cardiovascular disease and diabetes
- Body shape index, weight-adjusted waist index, and conicity index were better at identifying individuals at elevated COPD risk than traditional BMI
- Central fat distribution and visceral fat accumulation increase mechanical stress on the lungs and trigger inflammatory responses that accelerate pulmonary function decline
- Different obesity measures showed varying effectiveness: Chinese visceral adiposity index for cardiovascular disease and triglyceride-glucose index for diabetes risk
- The study included 4.3 million adults aged 35-75 followed for a median of 4.9 years with 38,674 documented COPD cases
Body mass index (BMI) has long been one of the most popular ways of identifying obesity and obesity-related health risks. But new research suggests it may fall short when it comes to assessing the risk for chronic conditions like COPD, cardiovascular disease and diabetes in people who are obese.
The paper, “Associations of Body Shape, Visceral Adiposity and Metabolic Function Indices With Risk of Major Noncommunicable Diseases: Evidence From a Nationwide Population Cohort,” was published in ScienceDirect.
According to a news release, the researchers analyzed data from 4,258,033 adults aged 35 to 75 years across China. Participants entered the cohort between November 2014 and December 2023. The researchers compared 15 indices reflecting body shape, visceral fat accumulation and metabolic function.
During a median follow-up of 4.9 years, the study documented 38,674 COPD cases, along with 329,073 cardiovascular disease events, 71,925 diabetes events and 113,373 cancer events.
The study examined how obesity-related measures were associated with the risk of these chronic diseases. Higher values of most measures were associated with higher risks of cardiovascular disease and diabetes. On the other hand, relationships with cancer and COPD were weaker and more complex, with some measures showing nonlinear or inverse associations.
The researchers wrote that these contrasting patterns suggest obesity-related health risks may differ substantially across diseases and may not be fully captured by a single measure.
The researchers then examined how well certain measures could distinguish individuals at different levels of disease risk. They looked at multiple obesity and metabolic indices, including:
- BMI
- Body roundness index (BRI)
- Waist-to-heigh ratio
- Body shape index
- Weight-adjusted waist index
- Conicity index
- Lipid accumulation product
- Chinese visceral adiposity index
- Triglyceride-glucose index
Of these, a body shape index, weight-adjusted waist index and conicity index showed relatively higher discrimination for COPD risk.
“This finding suggests that central fat distribution may be more pertinent for identifying individuals at elevated respiratory risk,” the researchers wrote. “Such a pattern may be attributable to differences in body composition phenotypes.”
In addition, the researchers reported that the accumulation of visceral and truncal fat may contribute to COPD pathogenesis through both mechanical and inflammatory mechanisms. This is because visceral and truncal fat increase the mechanical load on the thoracic cage, restrict diaphragmatic excursion, reduce chest wall compliance and impair ventilatory efficiency. This combination leads to an acceleration in the decline of pulmonary function, they said.
As for other conditions, the Chinese visceral adiposity index showed higher discrimination for cardiovascular disease risk, while the triglyceride-glucose index showed a higher discrimination for diabetes risk. The researchers found that all the measures had limited ability to discriminate overall cancer risk.
The researchers concluded that obesity-related health risks cannot be fully captured by BMI alone. Different measures capture different aspects of body fat distribution and metabolic health, and their associations and discriminatory ability vary across diseases.
“The development of diverse definitions for obesity measurement and management tailored to different population subgroups is warranted to optimize public health interventions and clinical decision-making,” they wrote.
