The Seventh Commandment and cancer
The authors of a recently published article claim to have found a reliable link between having ten or more sexual partners during a lifetime and an increased risk of developing cancer.
But it's not that simple. The data presented in the article are not convincing enough to conclude that there is a high risk of cancer among people who have told about several sexual partners during their lifetime. Let's figure it out.
Indeed, the presence of a sexually transmitted infection (STI) may increase the risk of some cancers, but estimating the number of a person's sexual partners as a marker of their likely sexual health is incorrect, and this is one of several shortcomings of this study.
How the study was conducted
The study, published in the journal BMJ Sexual & Reproductive Health, used data from 2,537 men and 3,185 women who participated in the English Longitudinal (long-term) study of aging, which involved adults in England over the age of 50 (average age 64). Most of them were married or lived with a partner, white, non-smokers, regularly consumed alcohol and were physically moderately active.
Participants were asked to recall the number of people they had ever had vaginal, oral or anal sex with. The researchers grouped the responses into four categories.
The number of sexual partners declared by the study participants.
Then the researchers studied the dependence of the results of self-assessment of health status (the presence of chronic diseases, cancer, heart disease and stroke) on the number of sexual partners during life.
The researchers took into account a number of demographic factors (age, ethnicity, marital status and socio-economic status), as well as health-related factors (smoking status, frequency of alcohol consumption, physical activity and symptoms of depression).
Research results
Men with 2-4 and 10 or more partners were more likely to be diagnosed with cancer than men with 0-1 partners. There was no difference between men with 0-1 partners and 5-9 partners.
Compared to women with 0-1 partners, women with 10 or more partners were more likely to be diagnosed with cancer.
Women with 5-9 partners and 10 or more partners were also more likely to report a "limiting chronic disease" than women with 0-1 partners. The authors do not specify what constitutes a limiting chronic disease, but if you look at the questions they asked the participants, you can understand that this is a chronic disease that disrupts daily activities.
There was no relationship between the number of sexual partners and self-assessment of overall health, the frequency of cardiovascular disease or stroke in men or women.
It is noteworthy that, despite the statistical significance of the findings, the magnitude of the effect of these associations was quite modest.
How does the number of sexual partners affect the risk of developing cancer?
Finding out the relationship between the number of sexual partners of a person throughout life and the risk of developing cancer is of great importance. The presence of several sexual partners in a person during his life indirectly indicates that he was most likely exposed to STIs. The presence of STIs, in turn, can increase the risk of developing several types of cancer.
For example, the human papillomavirus (HPV) is responsible for 30% of all cancers caused by infectious agents (bacteria, viruses or parasites), contributing to cancer of the cervix, penis, oral cavity and anus.
Viral hepatitis can be transmitted sexually, and chronic hepatitis B or C increases the risk of liver cancer.
Untreated HIV increases the risk of developing lymphoma, sarcoma and cervical cancer.
How to interpret the results of the study?
The authors of the article recognize the numerous limitations of the analysis and recommend that additional work be done to confirm their conclusions. Their use of the number of sexual partners throughout life as an indirect indicator of the history of sexually transmitted diseases is a key problem. There is a link between having more partners and an increased risk of STIs, but there are many other factors that may be important in determining the risk of STI infection.
Among them, for example: whether the participants practiced safe sex, what infection they might have encountered, whether they were vaccinated, whether they were treated for certain infections.
In addition, the analysis was based on cross–sectional data - a set of data taken at a certain point in time, it does not take into account changes over time. Participants were asked to recall information from the past instead of observing them at different points in time. It is impossible to identify a causal relationship from a cross-sectional analysis.
Even if the connection is confirmed in prospective longitudinal studies, the results may not be representative, that is, they do not apply to other groups of people.
Recent advances in vaccine development (e.g., the widespread availability of the HPV vaccine), better prevention of STIs (prevention of HIV before and after sexual contact) and more effective therapy (e.g., direct action of antiviral drugs for the treatment of hepatitis C) will reduce the impact of STIs on cancer risk.
People with more sexual partners smoked and drank more often (increasing the risk of cancer), but also led a more active lifestyle (reducing the risk of cancer).
For women, more sexual partners were associated with white ethnicity; for men, with more depressive symptoms. Although the researchers took these factors into account, these points highlight some inconsistencies in the structure of the results.
The researchers also failed to explain why more sexual partners were associated with a higher likelihood of limiting chronic disease for women, but not for men.
Ultimately, this study raises more questions than answers. Further research is needed before using these results to inform the public widely or to make changes in clinical practice.
In conclusion, the article says that a survey at the reception about the number of sexual partners during life can become one of the methods of finding a group of people with a high risk of developing cancer. Quite a bold statement, and such an approach can also be harmful. Such surveys violate privacy and may increase public condemnation of having multiple sexual partners or STIs. Fearing disapproval, people may stop visiting doctors for sexual health problems.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to the materials of The Conversation: Saying sex increases cancer risk is neither totally correct, nor in any way helpful.