People who have never been married are significantly more likely to develop cancer than people who are or have been married, and for some cancer types, the difference is striking.
This is the conclusion of a recent study from the University of Miami Miller School of Medicine. Researchers analyzed more than 4 million cancer cases in 12 states with populations of more than 100 million people, covering the years 2015 to 2022.
The findings showed that men who had never married were about 70% more likely to develop cancer than married men. Women who had never been married were about 85% more likely to develop cancer than women who had been or had been married.
For specific cancer types, the gaps were even wider:
- Anal Cancer in Men: The rate of anal cancer was approximately five times higher among unmarried men than among married men.
- Cervical Cancer in Women: The rate was almost three times higher among unmarried women than among women who were or had been married.
- Ovarian and endometrial cancer: Rates were lower in married women, partly because marriage is associated with higher rates of pregnancy, which has a known protective effect for these cancers.
Both anal and cervical cancer are strongly linked to an infection Human Papillomavirus (HPV)The higher rates among unmarried adults therefore reflect differences in risk and, in the case of cervical cancer, lower rates of screening and prevention.
Who was included – and who was not
The study included cancers diagnosed in adults aged 30 and older. The researchers placed participants into two groups: those who were or had been married (including divorced and widowed individuals) and those who had never been married.
The study’s timeline begins in 2015, when the U.S. Supreme Court legalized gay marriage, which allowed researchers to include same-sex couples in the married category.
One in five adults in the study had never been married.
The study did not include people who are single but in committed partnerships, a group the researchers believe is worth exploring in the future.
Cancer types and racial patterns
The strongest association between unmarried status and higher cancer rates appeared in cancers associated with infection, smoking or alcohol use. Associations with cancers with well-established screening programs, including breast, thyroid and prostate cancers, were weak.
Race also played a role. Black men who had never married had the highest cancer rates in the study. But married black men had lower cancer rates than married white men, suggesting that marriage may have a particularly strong protective association for that group.
The researchers also found that the gap between married and unmarried adults increased with age, suggesting that the health benefits associated with marriage may increase over time.
what the research shows
The study authors are careful to say that marriage does not magically prevent cancer.
Frank Penedo, PhD, associate director of population sciences at the Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, explains in a Summary Among the findings:
“This means that if you’re not married, you should pay extra attention to cancer risk factors, get any screenings you may need and stay up to date on health care.”
People who marry smoke less, drink less and are more socially connected, factors that independently reduce cancer risk. Still, researchers say the signal is clear enough to attract attention.
“With marriage becoming less prevalent in the United States, this deserves further study,” said co-author Dr. Paulo Pinheiro, a professor of cancer epidemiology at the Miller School.