Adults who have never married may face a significantly higher risk of developing cancer than those who are or have been married, according to a new U.S. study.

Researchers analyzed more than four million cancer cases across 12 states between 2015 and 2022, covering a population of over 100 million people. Their findings, published in Cancer Research Communications, show higher cancer risks across nearly all major types, particularly preventable cancers linked to infections, smoking, and reproductive factors.

The study, conducted by scientists at the Sylvester Comprehensive Cancer Centre at the University of Miami Miller School of Medicine, found cancer incidence rates were 68 per cent higher in never-married men and 85 per cent higher in never-married women.

Participants were divided into two groups: those who were or had been married, including married, divorced, and widowed individuals, and those who had never married. Couples living together without marriage were classified as unmarried. About 20 per cent of adults in the dataset had never married.

Overall, never-married individuals recorded significantly higher cancer rates. Never-married men had about five times the rate of anal cancer compared to married men, while never-married women had nearly three times the rate of cervical cancer. Both cancers are strongly linked to HPV infection, pointing to differences in exposure, as well as screening and prevention.

For reproductive cancers such as ovarian and endometrial cancer, researchers say lower childbirth rates among never-married individuals may partly explain the higher risks.

The study also found gender differences. Never-married men were about 70 per cent more likely to develop cancer than married men, while never-married women faced an 85 per cent higher risk.

This slightly reverses the usual trend in which men tend to benefit more from marriage, suggesting women may gain even greater protective effects in this context.

The strongest links between marital status and cancer were seen in cancers associated with infections, smoking, and alcohol use. In contrast, weaker associations were observed for cancers with established screening programs, such as breast, thyroid, and prostate cancer.

Racial disparities were also evident. Never-married Black men had the highest overall cancer rates, while married Black men had lower rates than married White men, suggesting a particularly strong protective association of marriage in that group.

Researchers caution that lifestyle factors may partly explain the findings, as people who smoke less, drink less, and maintain healthier habits may be more likely to marry.

However, the link between marital status and cancer risk was strongest among adults over 50, indicating that the benefits associated with marriage may increase over time.

“Social factors such as marital status may serve as important markers of cancer risk at the population level,” said study co-author Paulo Pinheiro.

Experts say the findings highlight the need for greater awareness. “If you’re not married, you should pay extra attention to cancer risk factors, get recommended screenings, and stay up to date with health care,” said Frank Penedo.

While marriage has long been linked to better cancer outcomes after diagnosis, fewer studies have explored its role in cancer risk. Researchers say future studies should examine how changes in marital status over time may influence cancer risk. (Nigerian Tribune)