Gaining weight during their late teens and 20s increases a man’s risk of dying from prostate cancer later in life, early research suggests.

An analysis of data from more than 250,000 men in Sweden indicated that weight gain over the course of a man’s life was associated with developing prostate cancer overall.

Scientists also found that the link with fatal prostate cancer was driven by weight gain between 17-29 years of age.

The findings, which are yet to be peer reviewed, were presented at the European Congress on Obesity in Dublin, Ireland.

Dr Marisa da Silva, from the Department of Translational Medicine at Lund University in Malmo, Sweden, said: “Knowing more about the factors that cause prostate cancer is key to preventing it.

“The only well-established risk factors, such as increasing age, a family history of the disease and several genetic markers, are not modifiable, making it vital to identify risk factors that can be changed.”

Prostate cancer is the most common cancer in men in the UK, with around 52,000 cases a year.

It is also the second most common cause of cancer death in men, with almost 12,000 deaths a year.

Previous research has shown excess body fat increases the risk of fatal prostate cancer.

To learn more about this association, Dr da Silva and her colleagues analysed data on 258,477 men who were part of the Obesity and Disease Development Sweden (ODDS) study from 1963-2014.

The men, who were free of prostate cancer when they enrolled in the study, were followed up until 2019 (median follow up 43 years).

Their weight had been measured at least three times between the ages of 17 and 60.

The data showed 23,348 participants were diagnosed with prostate cancer, with an average age at diagnosis of 70 years, and 4,790 men died from prostate cancer.

The team calculated that weight gain – equivalent to over half a kg (1.1lb) per year – was associated with a 10% greater risk of aggressive prostate cancer and a 29% greater risk of fatal prostate cancer.

Dr da Silva said: “Previous research has implicated elevated concentrations of insulin-like growth factor-1 (IGF-1), a hormone that is involved in cell growth and development, with an increased risk of prostate cancer.

“Levels of this hormone are raised in people with obesity and a steep increase in weight may fuel this elevation and the development of the cancer.”

The researchers said that preventing weight gain in young adulthood may reduce the risk of aggressive and fatal prostate cancer in later life.

Dr da Silva said: “We do not know if it is the weight gain itself or the long duration of being heavier that is the main driver of the association that we see.

“Nevertheless, one must gain weight to become heavier, so preventing a steep increase in weight in young men is imperative for the prevention of prostate cancer.”