A new study presented at a scientific conference reports that a measure of body shape should be performed and taken into account, in addition to body mass index (BMI), to better determine the risk of obesity-related cancers.

Cancer, and, obesity:, BMI, body, shape, combined, better, predict, risk

Obesity increases the risk of certain cancers, but to measure this risk, it would be better not to rely solely on the body mass index (BMI). This is the suggestion of a new scientific study, presented at the European Congress on Obesity (ECO), whose 2021 edition was recently held online.

Often criticized, the BMI measurement allows to measure the corpulence of a person from his weight and height. But it does not distinguish muscle from fat, nor does it take into account the distribution of body fat, gender or age of the individual. Conversely, the waist circumference gives an overview of a possible overweight and accumulation of fat in the abdomen, but does not take into account the size. This is why the scientific and medical community is working to find more appropriate and complete criteria. 

A body shape index to take more factors into account

In a new study, researchers from the University of Glasgow and Newcastle University in the United Kingdom have developed a "body shape index," or ABSI, that takes into account an individual's age, sex, weight, height and waist circumference. The team combined data from 442,614 participants (average age 56) from the UK Biobank, followed for an average of 8 years, during which time 36,961 people were diagnosed with cancer. 

Participants were divided into three groups based on body shape to find possible associations with risk of 24 different types of cancer; and to examine ABSI and BMI as predictors of cancer risk. Age, gender, ethnicity, income level, alcohol and tobacco use, diet, physical activity, and physical inactivity were considered as potential biasing factors.

The verdict: ABSI was associated with an increased risk of three cancers. Participants with the highest ABSI were 38% more likely to develop liver cancer, 40% more likely to develop lung cancer, and had a 17% increased risk of bowel cancer, compared with participants with the lowest ABSI, regardless of BMI. 

But the researchers found that taking into account ABSI combined with BMI was even better in terms of accounting for cancer risk. High ABSI combined with high BMI were linked to an increased risk of seven different types of cancer (uterine, esophageal, liver, stomach, kidney, bowel, breast). Thus, participants with the highest ABSI who were also overweight or obese in terms of their BMI (BMI greater than 25 kg/m2) were twice as likely to develop uterine cancer as those with the lowest ABSI and a normal BMI.

For the authors, these results invite to go beyond the calculation of BMI when estimating the risk of obesity-related cancers. Regardless of the method you use, overweight or obesity is the leading cause of preventable cancer after smoking," said Dr Carlos Celis-Morales, lead author of the study, in a statement.