Never-married people show higher risk of developing cancer, researchers find
It is not, to be clear, a cure for cancer. But a wide-ranging study has made a link between marriage and the disease. The bottom line: People who have never been married show a higher risk of cancer than those who are or have ever been married.
Researchers at the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine looked at cancer diagnoses in more than four million adults across 12 U.S. states, representing a population of over 100 million. They focused on cancers diagnosed after the age of 30 between 2015 and 2022.
They simplified a wealth of marital statuses into two broad groups: Ever been married and never been married. The “ever” camp included currently married, divorced and widowed individuals, as well as same-sex couples. The “never” group included those who lived with a partner but were not legally married. Roughly one fifth of the group fell into the never-married cohort.
Among never-married men, cancer rates were found to be 68 per cent higher than those who have ever been married. For women, the difference was even greater, with an increase of 83 per cent in those who have never been married.
Breaking the numbers down by age showed that older married adults were more likely to benefit from this trend, “ suggesting that differences associated with marital status may accumulate over the life course,” the researchers wrote.
“In contrast, smaller (incidence rates) among adults ages 30 to 54 years likely reflect selection processes, whereby individuals with more favourable baseline health, behaviours, or resources are more likely to marry,” they added.
There were racial differences as well. Never-married Black men had the highest incidence of cancer among all groups. However, among ever-married men, Black men had even lower rates than White men.
Not every type of cancer showed the same difference. Researchers looked at incidents of anal cancer in men and cervical cancer in women, two types closely linked to infection with the sexually transmitted human papillomavirus or HPV.
They found that never-married men had more than five times the rate compared with ever-married men. Never‑married women had almost three times the rate compared with ever-married women.
Reasons for the disparity in the different groups is probably a mix of society and biology. On the former front, being married may increase the chance of being reminded by a spouse to attend medical appointments, or could result in more stable healthcare and insurance.
Meanwhile, a higher rate of endometrial and ovarian cancers in never‑married women could be the result of lower rates of childbearing in that group. Pregnancy and childbirth alter hormone exposure in ways that can reduce risk, as other research has shown .
“Marital status is often treated as a background demographic variable,” the researchers noted. “Yet, our findings suggest that it may function as a social exposure that captures dimensions of cancer risk not fully explained by race, age, or socioeconomic status.”
They added: “It may serve both as a marker of cumulative social advantage and as a multifactorial exposure encompassing behavioural, psychosocial, and healthcare-related factors, such as sexual behaviour, parity, tobacco and alcohol use, diet, and engagement with preventive care.”
The scientists also noted limitations in their study.
“Legal marital status is a heterogeneous administrative classification that does not directly measure social support, partnership quality, cohabitation, or relational stability,” they noted. “Individuals in long-term cohabiting relationships may experience levels of emotional and instrumental support similar to married individuals yet are classified as never-married in registry and census data.”
Conversely, they noted, people in strained or abusive marriages may not experience protective social benefits.
“Legal marriage should not be interpreted as a direct proxy for social support but rather as a structural and institutional marker that may correlate with broader social and behavioral patterns influencing cancer risk,” they wrote.
Nevertheless, they said, “Given that approximately 20 per cent of adults (aged 30 and older) are never-married, the population-level impact of this disparity is substantial.”
And as with most medical studies, the final word is that more research is needed. Expect some scientists presented with the question of whether they want to dig deeper into the topic to answer: “I do.”
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