The study found that women who have had at least 10 sexual partners during their lifetimes were 91% more likely to develop cancer than women with one or zero partners. Similarly, men with 10 or more partners were 64% more likely to be diagnosed with cancer than those with one or zero partners.
The study was based on 2,537 men and 3,185 women in the UK who are at least 50 years old and part of the English Longitudinal Study of Aging. The average age of the study participants was 64.
The researchers used logistic regression to determine the link between the number of sexual partners and cancer risk, adjusting for “sociodemographic and health-related covariates.”
“Previous research has shown that specific STIs (sexually transmitted infections) may lead to several cancers,” one of the study’s authors, Lee Smith, is quoted as telling Reuters.
“It is interesting the risk is higher in women when compared to men. This may be because the link between certain STIs and cancer is stronger in women,” he added.
The study also found that men were three times more likely to have 10 or more sexual partners compared to women. Only 16% of women surveyed had between five and nine sexual partners. In addition, women with 10 or more sexual partners were 64% more likely to report a limiting, long-standing illness compared to women with only one or zero sexual partners. However, the researchers were not able to pinpoint differences between the men and women’s self-rated health based on the number of sexual partners they had during their lifetimes.
However, Dr. Robert Edwards, a professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine who was not involved in the study, said that the link between sexual partners and cancer might be more related to lifestyle choices than to the act of sex, as people who had more partners were more likely to smoke and drink alcohol.
“People who had risky sexual encounters should contact their health care providers to get checked for potential sexually transmitted infections and should discuss openly how to minimize this risk with their health-care providers,” Smith told Reuters. “Using appropriate protection will reduce the risk of related cancers going forward.”