Notching up plenty of bedroom conquests can nearly double your cancer risk, a study reveals.
Experts found older women who had ten or more lifetime lovers were 91 per cent more likely to be diagnosed with the disease, compared to those who only had one.
And promiscuous men saw their chances of a tumour rocket by 69 per cent.
Many cancers – such as cervical, prostate and oral – are linked to sexually transmitted infections.
Anglia Ruskin University scientists think this is the reason why adults with large numbers of partners are more likely to be diagnosed with the disease.
Writing in the journal BMJ Sexual & Reproductive Health, lead researcher Dr Lee Smith said: “In both men and women, a higher number of sexual partners was associated with increased risk of cancer.
Sexually transmitted infections
“The heightened risk of cancer might be driven by those types known to be associated with sexually transmitted infections.”
Around 363,000 Brits are diagnosed with cancer each year.
The team analysed data on 5,722 older Brits with an average age of 64.
As well as showing a link between the number of sexual partners and cancer risk, researchers also found women with more than ten lovers were two-thirds more likely to suffer a long-term illness, such as diabetes or heart disease.
Natasha Paton, Cancer Research UK’s health information manager, said: “This is an interesting piece of research but unfortunately it didn’t fully take into consideration two key cancer risk factors – smoking and weight.
“We also don’t know which cancer types were linked because the number of cases diagnosed in the study was too small.
“People who have had more sexual partners may have an increased risk of HPV infection, which is passed through skin to skin contact and can cause some less common cancers.
“But HPV is a very common infection and unlikely to be the cause here since most people will have it at some point in their life without it leading to cancer.
“Rather than worrying about your number of sexual partners, the best thing you can do to reduce your risk of cancer is to stop smoking, keep a healthy weight and cut down on alcohol.”