Having more than 10 sexual partners over a lifetime is linked to an increased chance of getting cancer, the researchers say.
And women with a higher number of sexual partners are more likely to report a limiting condition in the long run, experts from the UK, Austria, Turkey, Canada and Italy have discovered.
The researchers analyzed data from adults aged 50 and over in England, with 5,722 participants reporting the number of sexual partners they had.
About 22% of men and just under 8% of women have reported 10 or more sexual partners.
The researchers found a statistically significant association between the number of lifetime sexual partners and the risk of a diagnosis of cancer between men and women.
Data from the English Longitudinal Study on Aging (ELSA) showed that adults assess their health and any long-term conditions on a questionnaire in 2012/13.
Those who had more sexual partners were younger, more likely to smoke, drink frequently, and exercise more vigorously each week, the researchers said.
Compared to women who reported 0-1 sexual partners, those who claimed to have had 10 or more partners had 91% more chance of being diagnosed with cancer.
Men who reported 2-4 lifetime sexual partners were 57% more likely to have been diagnosed with cancer than those who reported 0-1.
And those who reported 10 or more were 69% more likely to have been diagnosed with the disease.
The study, published in BMJ Sexual & Reproductive Health, also found that women who reported five to nine, or more than 10 lifetime sexual partners were 64% more likely to have a chronic limiting condition than those who claimed to have had 0-1.
The researchers – who claimed that the average age of the participants was 64 and that nearly three quarters were married – found no such association in men.
Although the study does not establish the cause, it mirrors previous findings linking sexually transmitted infections in the development of several cancers and hepatitis.
The small number of cancer diagnoses in the participants meant that researchers were unable to analyze the results by type of cancer.
If a causal relationship can be established in the future, the authors suggest that asking people how many sexual partners they have had could help cancer screening programs.
They write: “It should be noted that the number of lifetime sexual partners is associated with the limitation of long-standing diseases in women and not men.
“This gender difference is interesting, but one explanation is elusive, especially when men have more lifetime sexual partners than women, as shown in this study, and women are more likely to seek medical screening for IST and therefore are less likely to experience long-term negative health complications.
“Further research is needed to identify the mechanisms that explain this observed association and the divergent pattern between men and women.”