Nearly half of all cancer cases are linked to obesity

The study led by Lund University in Malmo, Sweden, involved 4.1 million participants who were monitored for about 40 years, with close monitoring of their weight and lifestyle.

Over the period, 332,500 cancers were identified. In 40 per cent of cases, there appeared to be a link between excess weight and the development of cancer.

There are an average of 390,000 cancer diagnoses in the UK annually, meaning that around 150,000 of them could be linked to obesity.

In total, researchers identified 32 types of cancer with an obesity link.

Previously, international research had identified 13 types of cancer which were linked to being overweight or obese, including bowel, breast, womb and kidney. The new study found that a five-point increase in Body Mass Index (BMI) appeared to increase the risks of such cancers by 24 per cent for men and 12 per cent for women.

The same increase – enough to take someone from the threshold for healthy weight to the cusp of obesity – was linked to 19 other cancers, with the risk raised by 17 per cent for men and 13 per cent for women. These cancers include malignant melanoma, gastric tumours, cancers of the small intestine and pituitary glands, as well as types of head and neck cancer, vulval and penis cancer.

In total, researchers examined 122 types and subtypes of cancer in a study which tracked patients over 100 million years of follow-up.

“The findings of this study have important public health implications. Established obesity-related cancers accounted for 25 per cent of all cancer cases in this study, and the proportion increased to 40 per cent when potential obesity-related cancers were added. Therefore, a substantial proportion of cancers could potentially be prevented by keeping a normal weight,” researchers said.

Obesity rates have almost doubled in the UK since the 1990s, with 26 per cent of adults in England now classed as obese, while 38 per cent are overweight.