A study of more than 400,000 adults shows that in addition to a high body mass index, a larger waist and hips also pose a risk of developing ten of the most common cancers.
- To estimate the risk of cancer linked to overweight, it is necessary to take into account not only the body mass index (BMI) but also the central adiposity, that is to say the percentage of fat located at the waist and hips.
- Obesity increases the risk of developing certain cancers by up to 73%, and the risk of general cancer by 3%.
Cancer is the second leading cause of death worldwide and obesity has long been identified as one of the main risk factors. A new study of more than 400,000 UK adults shows that body mass index (BMI) is not the only measure to consider when estimating cancer risk from being overweight. Presented at the European Congress on Obesity (ECO) held online this year, it shows that central adiposity (larger waist and hips) is to be taken into account in addition to general obesity (BMI and body fat percentage) to estimate cancer risk.
An increased risk of 10 of the most common cancers
To reach this conclusion, researchers from the University of Glasgow (Scotland) used data from the UK Biobank prospective cohort study. They identified 437,393 adults (54% women; mean age 56) who were cancer-free, to study the risk of developing and dying from 24 cancers based on six markers of obesity: BMI , body fat percentage, waist to hip ratio, waist to height ratio, and waist and hip circumference. After an average follow-up of 9 years, 47,882 cases of cancer and 11,265 cancer deaths were recorded.
The researchers found that all six measures of obesity were positively and similarly associated with a higher risk of 10 cancers. Thus, every 4.2 kg/m2 (in men) and 5.1 kg/m2 (in women) of BMI above 25 kg/m2 (defined as overweight) was associated with a risk more than 35% high for stomach cancer, 33% for gallbladder cancer, 27% for liver cancer, 26% for kidney cancer, 12% for pancreatic cancer , 9% for the bladder, 10% for the colon and rectum, 73% for the endometrium (73%), 68% for the uterus (68%), 8% for breast cancer post-menopausal and 3% for the risk of cancer in general.
Based on the results, the researchers estimate that if these associations were causal, overweight or obesity could be responsible for around 40% of endometrial and uterine cancers and 29% of gallbladder cancers. biliary. Overweight could also be respectively the cause of 64%, 46% and 40% of deaths from these cancers.
“We observed a linear association – the more severe the obesity, the higher the risk of developing and dying from these cancers, with the exception of postmenopausal breast cancer, explains Dr Carlos Celis-Morales of the University of Glasgow, who led the research. But the effects of obesity on different cancers vary widely. This tells us that obesity must affect cancer risk through a different number of processes, depending on the type of cancer.r.”
The researchers specify that this is an observational study: it cannot therefore establish a cause. They therefore cannot exclude the possibility that other unmeasured factors may have influenced the results.
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