Close to half of all cancer diagnoses linked to obesity, research finds

A pivotal study has revealed a significant correlation between obesity and an increased risk of various cancers, intensifying concerns over a looming public health crisis. Conducted at Lund University in Malmo, Sweden, this extensive research tracked over four million adults over four decades, uncovering that excess weight could be a contributing factor in more than 30 different types of cancer.

This landmark research, set to be unveiled at the European Congress on Obesity in Venice, has been described as “groundbreaking” by experts, highlighting a potential health crisis in the making. The urgency of these findings has prompted health charities to call for immediate governmental action in response to this alarming revelation. They emphasise the economic burden of obesity, which is estimated to cost the UK nearly £100 billion annually, with NHS expenses alone reaching £19 billion.

The Health Secretary, Victoria Atkins, asserted the government’s commitment to addressing this issue robustly, with plans to leverage apps and technology to transform public health approaches expected to roll out this summer. Atkins stressed the government’s goal for citizens to enjoy longer, healthier lives.

Detailed findings from the study indicated that, of the 332,500 cancer cases recorded during the research period, 40% could be linked to obesity. Annually, the UK sees around 390,000 new cancer diagnoses, suggesting approximately 150,000 cases could be obesity-related. Previously, global studies had identified 13 cancers linked to excess weight, including cancers of the bowel, breast, womb, and kidney. This latest study has extended that list, identifying a total of 32 cancer types associated with obesity. Notably, a five-point increase in Body Mass Index (BMI) was found to enhance cancer risks significantly—by 24% in men and 12% in women for previously established obesity-related cancers. Additionally, this increase was connected to a 17% higher risk for men and 13% for women in 19 other newly associated cancers, including malignant melanoma and various rare cancers like those of the pituitary glands and small intestine.

The comprehensive nature of the study, examining 122 types and subtypes of cancer over 100 million years of follow-up, underlines the severe public health implications. Researchers highlighted that keeping a normal weight could potentially prevent a substantial proportion of cancer cases, with established obesity-related cancers accounting for 25% of all cases and this proportion rising to 40% when including potential obesity-related cancers.

Obesity rates in the UK have nearly doubled since the 1990s, with a current 26% of adults in England categorised as having obesity and another 38% as having overweight. Obesity now surpasses smoking as the primary cause of four major cancers, though smoking remains a significant risk factor.

Forecasts by Cancer Research UK suggest that reducing obesity could prevent approximately 8,000 cancer cases in England by 2040. Prof Jason Halford, president of the European Association for the Study of Obesity, emphasised the strength of the analysis and the need for further research to confirm these associations and explore the underlying mechanisms.

The NHS is exploring innovative approaches, including the use of weight loss medications like Wegovy, to tackle obesity effectively. Government plans to promote healthier lifestyles through technology and legislative measures are also underway, aiming to make healthy choices more accessible to the populace.

Katharine Jenner, director of the Obesity Health Alliance, a coalition of 50 health charities, stressed the clear results of the study and the need for urgent, effective public health policies to prevent obesity and associated diet-related cancers. This includes implementing restrictions on junk food marketing and introducing levies on unhealthy foods to facilitate healthier choices for all.

Lead researcher Dr Ming Sun highlighted that the impact of obesity on cancer might be more extensive than previously understood, suggesting it as a risk factor for more cancer types, particularly rarer ones that have seldom been studied in this context. The study’s findings underscore the necessity of public health measures to tackle the obesity epidemic and its detrimental effects on health outcomes comprehensively. Dr Jennifer L Baker, co-chairman of EASO’s childhood obesity working group, further elucidated potential biological mechanisms such as chronic inflammation and hormonal changes that might explain the increased cancer risk associated with obesity.

In conclusion, this study serves as a critical indicator of the link between obesity and an increased risk of various cancers, urging immediate and robust action to mitigate this public health threat.