- A new study suggests that people who’ve had 10 or more sexual partners in their lifetimes have a heightened risk of developing cancer.
- Certain sexually transmitted diseases like HPV, if left untreated, can lead to cancer.
- There are other risk factors for cancer risk, like weight and smoking status.
- Visit Insider’s homepage for more stories.
Comparing your “number,” that is the amount of people you’ve had sex with in your lifetime, is often hush-hush banter among friends, but a new study suggests that number could have an affect on a person’s cancer risk.
The study, published February 13 in the journal BMJ Sexual & Reproductive Health, found that men who reported having 10 or more sexual partners in their lifetimes were 69% more likely to have a cancer diagnosis of any kind, compared to those with one or no sexual partners. Women with 10 or more sexual partners were 91% more likely to develop cancer.
“We expected there to be an association between number of sexual partners and cancer risk, as previous research has shown that specific sexually transmitted infections may lead to several cancers,” Dr Lee Smith, senior author of the paper, told Insider. “Indeed, a higher number of sexual partners means greater potential exposure to STIs.”
The study had plenty of caveats, including that it did not look at specific types of cancer. Smith, a sport and science researcher at Anglia Ruskin University in Cambridge, England, said the database they used didn’t offer that information. They study also left out information on participants’ smoking habits, an important cancer risk factor.
Women with 10 or more sexual partners had a higher cancer risk than men with the same number
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For the study, the researchers looked at existing data for 2,537 men and 3,185 women who were 50 or older, and all British, from 1998 to 1999 to 2001.
First, they grouped the men and women into categories based on how many sexual partners they reported having in their lifetimes: up to one partner, one to four, five to nine, or 10 or more. They also looked at the various chronic disease the men and women reported having, including all cancer, heart disease, and stroke.
Women’s risk was slightly higher than men’s if they had 10 or more partners, which Smith told Insider was a surprising finding.
“This may be because the link between certain STIs and cancer is stronger in women, such as HPV and cervical cancer, compared to HPV and penile cancer,” in men, Smith said.
HPV is an STD that can result in symptoms like genital warts, but is typically asymptomatic, Insider previously reported.
For that reason, a person may have HPV without knowing it and spread it to someone else, contributing to the statistic that 14 million new HPV infections happen annually in the United States, according to the American Sexual Health Association. HPV, if left untreated, can lead to cervical or anal cancer.
Weight and smoking status are other cancer risk factors that study didn’t account for
The conclusions researchers drew came from an existing database, rather than original research, and as a result it’s possible the correlation they observed was a coincidence, not a definite indication that having more sexual partners leads to heightened cancer risk.
For this reason, Smith said he’d like to see future research aimed at the link between number of sexual partners and specific cancers.
“This is an interesting piece of research but unfortunately it didn’t fully take into consideration two key cancer risk factors – smoking and weight,” Natasha Paton, a health information manager for Cancer Research UK, told The Sun.
“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,” Paton said.
Additionally, the study only looked at British people who were 50 or older, so the findings aren’t representative of everyone who has sex. In the United States, for example, men under the age of 30 report having 26 sexual partners on average, and women of the same age report 19 on average, but this data wouldn’t be able to shed light on their health risks.
The data the study relied on also used self-reported information, so it’s possible the men and women were not entirely truthful about the actual number of sexual partner’s they’d had.
Experts hope the study will encourage older people to practice safe sex
Smith said he hopes his study acts as a reminder for older people who are sexually active that there are risks associated with unprotected sex, particularly sexually-transmitted infections.
“Older adults should follow safe sex practices and if they have engaged in ‘risky’ sexual activity they should consult a health care provider,” Smith said.