Hundreds of lives could be saved from prostate cancer if men lost weight, a major study has found.
Experts from the University of Oxford examined the body measurements of more than 2.5 million men.
Every five point increase in BMI – about 2.5 (35 pounds) for the average British man – was associated with a 10% higher chance of dying from prostate cancer.
Five points are enough to take a person from a healthy weight to an overweight person, or from an overweight person to obese.
Researchers estimate that the bulging waist is responsible for 1,300 prostate cancer deaths in Britain each year.
Prostate cancer is the most common cancer in men in the UK, with around 52,000 diagnosed each year. In the United States, about 165,000 are diagnosed, with nearly 30,000 deaths.
Every five point increase in body mass index (BMI) – equivalent to around 2.5 stone in the average British man – increases the risk of death from prostate cancer by 10%
Dr Aurora Perez-Cornago and colleagues said: ‘We found that men with higher total and central adiposity had a higher risk of dying from prostate cancer than men with a healthy weight.
“Knowing more about the factors that increase the risk of prostate cancer is essential to prevent it.
“Age, family history and black ethnicity are known risk factors but they are not modifiable, so it is important to find out which risk factors can be modified.”
She said several biological reasons for the increased risk have been proposed, although the disease may be harder to detect in obese men, meaning it is diagnosed at a later stage when it is more difficult to deal with.
Dr Perez-Cornago added: ‘More research is needed to determine whether the association is biological or due to delays in detection in men with higher adiposity.
“In either case, our latest results provide another reason for men to try to maintain a healthy weight.”
The results were presented today at the European Obesity Congress in Maastricht, the Netherlands, and simultaneously published in the journal BMC Medicine.
Simon Grieveson, from Prostate Cancer UK, said: “This large-scale study suggests that being overweight is associated with an increased risk of dying from prostate cancer.
“While these findings are compelling, more research is needed to fully understand the biological relationship between obesity and prostate cancer and, importantly, how we can use this information to improve outcomes for men.
“Maintaining a healthy weight can protect against many cancers, but it’s important to remember that prostate cancer can affect men of all shapes and sizes.
“Men over 50, black men and men with a family history are most at risk for the disease and should speak to their doctor if they have any concerns.”
The researchers followed the men’s medical records, for an average period of about 12 years.
The men were between the ages of 40 and 69 and had not been diagnosed with cancer before the start of the study.
Some 661 people died of the disease at the end of the follow-up period.
Their BMI scores, body fat percentages, waist circumferences and waist-to-hip ratios were recorded to see how these affected the development and severity of the cancer.
Using statistical analysis, the team found that a larger waist circumference and waist-to-hip ratio increased the risk of dying from prostate cancer.
Those in the top quarter for both measures saw a roughly 25% higher risk of dying from the disease than those in the bottom quarter.
Every 10 cm (3.9 inches) extra on a man’s height increases his chances of dying from prostate cancer by 7%.
But having a higher body fat percentage had no effect on the risk of death, the data showed.
A separate study presented at the congress claimed that getting at least six hours of sleep a night is crucial to keeping your weight under control.
Researchers from the University of Copenhagen in Denmark examined sleep duration and quality in nearly 200 obese adults for one year.
People who slept less than six hours a night saw their BMI score increase by 1.3 points after one year compared to those who slept more than six hours.
According to studies, more than a third of UK and US adults sleep less than six or seven hours a night due to stress, screens and blurring or blurring of work-life boundaries.