Older people who have had 10 or more sexual partners in their lifetime have a higher rate of cancer. The reasons why remain uncertain at this time, but sexually transmitted infections (STIs) such as hepatitis B virus (HBV) and human papillomavirus (HPV), each of which can cause cancer, may be key factors.

Lee Smith, PhD, of Anglia Ruskin University in Cambridge, England, and colleagues analyzed data from the English Longitudinal Study of Ageing, a nationally representative study that follows English individuals age 50 and older. They looked specifically at 2,537 men and 3,185 women who, between 2012 and 2013, responded to questions about their number of lifetime sexual partners.


On average, the participants were 64 years old, and about three quarters were married. Twenty-nine percent of the men reported zero or one sexual partners in their lifetime, while 29% reported two to four partners, 20% reported five to nine partners and 22% reported at least 10 partners. The corresponding proportions of women reporting the same numbers of partners were 41%, 36%, 16% and 8%.


Having 10 or more partners was associated with being younger, single and in the highest or lowest income brackets among both men and women. People in the group with the highest number of sexual partners were more likely than those with fewer than 10 partners to smoke, drink frequently and engage in weekly vigorous physical activity.


The study authors found that compared with men reporting zero or one sexual partners,  men reporting two to four partners were 57% more likely than to have been diagnosed with cancer, while men who reported 10 or more partners were 69% more likely to receive a cancer diagnosis. And among the women, those reporting 10-plus sexual partners were 91% more likely than those reporting zero or one partners to have been diagnosed with cancer.


The study authors lacked key data that could have identified which factors might have mediated the increased risk of cancer among those with 10-plus partners. HPV, for example, can cause cancer of the cervix, anus, vulva, vagina, penis and mouth and throat, while hep B can cause liver cancer. Smoking and drinking raise the risk of several types of cancer, while exercise has a protective effect.


"It is possible that the number of sexual partners one has had captures a combination of likelihood of exposure to STIs and lifestyle profile,” the study authors concluded.

To read a press release about the study, click here.

To read the study abstract, click here.