New obesity framework identifies disease more accurately than BMI

A new international study says a diagnostic framework that considers waist measurements and organ function can distinguish harmful obesity from excess body fat more accurately than body mass index alone. ERR reported that the researchers analysed health records for more than 840,000 adults in China, the United Kingdom, the United States and Spain.

The framework, developed last year by a Lancet commission, supplements weight and height measurements with waist circumference and the waist-to-height ratio. The researchers say these measures help doctors assess where fat is located and whether it is affecting the organs.

The system distinguishes between clinical obesity, an active disease that directly impairs organ function, and preclinical obesity, in which excess fat is present but organs function normally. Relying only on BMI can lead to both overdiagnosis and missed cases: the study found that the old approach failed to identify almost 9% of people with dangerously high levels of body fat.

Using the new framework increased the share of people classified as having obesity by 3% to 7% in all four countries. Clinical obesity accounted for nearly a third of diagnoses and affected about 6% to 11% of the population. People with clinical obesity had a significantly higher overall risk of death. Higher mortality was seen only among patients who had both excess weight and a larger waist circumference.

By contrast, 77% to 91% of people with preclinical obesity did not develop active disease over 10 years, the researchers said. Francesco Rubino, a professor at King’s College London, said BMI alone does not show what support a patient needs and can lead to unsuitable treatment. Study author An Pan, a professor at Huazhong University, said the findings support wider use of the framework, as the differences between the two stages appeared across all the populations studied.