Married people are less likely to develop cancer, a study involving the records of four million people has found.
Men who were never married were about 70 per cent more likely to develop cancer than married men, while unmarried women increased their cancer risk by 85 per cent.
For some cancers, the risk was even higher, with unmarried men at five times the risk of anal cancer, and women three times more likely to develop cervical cancer.
Although the US researchers are not sure what is causing the effect, they believe that some lifestyle factors, such as more sexual partners and greater exposure to human papillomavirus (HPV) for single people, may explain some of the increased risk.
Married people are also more likely to spot changes in their partners that signal cancer, leading to earlier diagnosis, as well as ensuring their spouses sign up for screening and medical checks, eat healthily and take medication.
Cancer experts from the University of Miami Miller School of Medicine said that it was not a “prescription to marry” but rather a warning to unmarried people that they needed to keep a closer eye on their health.
“It means that if you’re not married, you should be paying extra attention to cancer risk factors, getting any screenings you may need and staying up to date on healthcare,” said Dr Frank Penedo, professor of psychology and medicine.
Marriage has fallen in Britain, from seven in 10 adults married in the 1970s to fewer than half today. If current trends continue, fewer than a third of people will be married by 2050.
The research suggests that as marriage rates decline, cancer rates may start to increase, and doctors should take into account marital status when assessing cancer risk.
“Marriage as a protective factor in cancer risk has been largely ignored so far,” said Dr Paulo Pinheiro, a professor of cancer epidemiology at the Miller School Department of Public Health Sciences.
“These findings suggest that social factors such as marital status may serve as important markers of cancer risk at the population level.
“With the prevalence of marriage decreasing this is something that should be further studied.”
For the study, experts analysed health records of more than four million cancer patients across 12 US states between 2015 and 2022.
Marriage previously found to have protective effect
The strongest associations between marriage and cancer were for those related to infection, smoking or alcohol use and, for women, cancers related to reproduction, such as ovarian and endometrial.
Black men who were never married had the highest overall cancer rates. However, married black men had lower cancer rates than married white men.
Marriage has previously been found to have a protective effect in other areas of health.
In 2019, University College London found that married men and women over 60 were more physically capable than their unmarried, widowed or cohabiting peers.
On average, British men who were in their first marriage had a 0.73kg stronger grip than men who were widowed or never married.
In England, married men walked 3.1 inches (8 cm) per second faster than widowers and 4.3 inches (11 cm) faster than singletons, a sign of good health. Married women also walked up to 3.1 inches quicker than singles.
In 2011, the University of Rochester found married people who underwent coronary bypass surgery were more than three times as likely to be alive 15 years later than their unmarried counterparts.
The previous year’s research by the World Health Organisation found marriage could reduce the risk of anxiety and depression and those who tied the knot were much less likely to suffer the blues than those who stayed single.
But the team has warned that the study does have limitations. People who smoke less, drink less, take better care of themselves and are more socially integrated may also be more likely to get married.
“The association between marriage status and cancer risk is an interesting, new observation that deserves more research,” said Dr Pinheiro.
The research was published in the journal Cancer Research Communications.
