Those who first reported being overweight at the age of 20 were around 60-80 per cent more likely to develop these cancers in later life, compared to those who maintained a healthy weight throughout life.
People who gained more than three stone (20kg) during adulthood were also twice as likely to develop esophageal cancer compared to people who had little weight change.
The study, led by researchers from the National Cancer Institute in Bethesda, US, pooled data from more than 400,000 people and analysed their reported height and weight at ages 20, 50, and at the time they gave the information. The researchers then followed them up to see which people developed cancer of either the esophagus or upper stomach.
Study leader Dr Jessica Petrick, said: “This study highlights how weight gain over the course of our lives can increase the risk of developing these two cancer types, both of which have extremely poor survival.
“Carrying excess weight can trigger long-term reflux problems and heartburn that can lead to cancer. It can also change the levels of sex hormones, such as oestrogen and testosterone, cause levels of insulin to rise, and lead to inflammation, all of which are factors that have been associated with increased cancer risk.”
Around 5,600 people are diagnosed with esophagus (food pipe) and upper stomach cancers in England every year. Being overweight or obese is the single biggest preventable cause of cancer in the UK after smoking and contributes to around 18,100 cases of cancer every year. In addition to cancers of the esophagus and the upper stomach, it is linked to a range of other cancer types including bowel, breast, liver and pancreatic.
Sarah Williams, health information manager at Cancer Research UK, said: “This study further highlights the importance of keeping a healthy weight throughout life to reduce the risk of developing these cancers. Small steps like taking the stairs more often, keeping an eye on portion sizes and switching to sugar-free drinks are simple things we can all do to help keep a healthy weight.”
“Participants were asked to recall what they weighed at different ages. Memories aren’t always accurate over long periods of time, so it will be interesting to see if these findings are backed up by future studies looking at lifetime weight gain and cancer risk in real time.”