Published on: 31st July 2017
Citizen Driven Health
Case Study 84
Research lead: Dr Hannah Lennon, University of Manchester
By analysing data, researchers at The University of Manchester have investigated the link between people’s BMI measurements and obesity-related cancers.
Many cancers can take years or even decades to develop. It is believed that one in twenty cancers in the UK is linked to a high Body Mass Index (BMI), with this absolute number likely to increase with the growing obesity epidemic. The aim of this project was to use people’s data to study the effect of BMI throughout life on obesity-related cancer risk.
The data from over half a million people in the US was analysed and researchers investigated how the types and number of cancers related to people’s BMI measurements throughout their lifetime. The obesity-related cancers looked at were bowel, breast, pancreatic, oesophageal, gastric cardia, kidney, gallbladder, liver, ovarian, cervical, thyroid and multiple myeloma.
By looking at high BMI levels throughout an entire lifetime, rather than only assessing a person’s BMI at one single time point, it is possible to look at the long term effects that higher BMI measurements have on the risk of cancer. This information was used to evaluate how the different BMI histories or trajectories through life increased people’s cancer risk.
Our study identified that the population can be divided up into five different groups, each with their own BMI trajectory type.
One of these represented lean individuals who increased in weight very slowly over their lifetime. The other four groups included those who rapidly gained weight but never lost it, and people who began with a high BMI and maintained this throughout their life – these individuals were found to be at a relatively higher risk of developing an obesity-related cancer.
Risks were around 50% higher for men and 25% higher for women in people showing high BMI readings for longer periods of time compared with lean individuals.
It was the aim to understand more about the complex relationship between obesity and cancer and look at whether the way people gain weight has a real impact on their risk of developing the disease.
It is already known that having a high BMI increases the likelihood of developing some types of cancer but this research explores weight across an individual’s lifetime, allowing more detailed analysis on the different ways that extra weight can affect the development of cancer.
This study showed those rapidly putting on weight are at increased risk of developing certain cancers and these results give further emphasis to the importance of public health initiatives to help and encourage everyone to maintain a healthy lifestyle.
The World Health Organization (WHO) state that being overweight and obesity are the most important known avoidable causes of cancer after tobacco.
Dr Hannah Lennon, lead author and researcher at The University of Manchester, said: “This research shows how important it is to look at weight gain over a person’s lifetime – to give a clearer picture of cancer risk through life, compared to assessing someone’s BMI at a single point.
“This study could also be really useful in public health. It could help identify people who would benefit the most from taking action to control their weight before any health problems arise – including a cancer diagnosis.”The project gathered interest in the press and was picked up by the Independent, the Daily Express, the Daily Telegraph, and the Daily Mail, plus many more online publications in France, Germany, Australia, Thailand and China, to name a few.
Lennon, H., Sperrin, M., Badrick, E. et al. Curr Oncol Rep (2016) 18: 56. https://doi.org/10.1007/s11912-016-0539-4
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