A major US analysis links unmarried status to a higher incidence of most cancers, revealing how social and behavioral factors may shape risk across the lifespan.
Study: Marriage and cancer risk: A contemporary population-based study across demographic groups and cancer types. Image credit: Yuganov Konstantin / Shutterstock
A recent study published in the journal Cancer Research Communications suggests that marital status may be associated with differences in cancer risk in the United States (US). Using population-level data, the researchers found that never-married adults, particularly black men, had a significantly higher incidence of most cancers.
The risk was 68% higher in men and 83% higher in women compared to ever-married individuals, with the strongest associations seen in those aged ≥55 years.
Findings suggest cumulative behavioral and social influences, although some observed differences may also reflect marriage choice, with important implications for cancer prevention and public health strategies, especially in aging populations and underserved communities.
Marital Background, Social Support, and Cancer Risk
Marriage has been associated with improved health outcomes, including longer survival, lower morbidity, and better self-reported health, primarily due to stronger social support, healthier behavioral habits, and greater financial stability. By middle age, celibates are also more likely to experience adverse physiological changes, characterized by inflammation and metabolic dysregulation.
Married people tend to receive earlier cancer diagnoses and have more favorable outcomes. However, the relationship between marital status and cancer incidence remains unclear.
Existing evidence is limited by outdated, small, or site-specific studies that are often based on clinical or healthcare-based samples and are prone to bias. In addition, changing social norms and risk factor patterns underscore the need for updated population-level research.
Design of a US Cancer Incidence Study
In the present study, researchers assessed cancer incidence by marital status, location of cancer, age, sex, and race/ethnicity. They analyzed data from surveillance, epidemiology and outcomes (PROPHET) program covering 12 US states.
These included Connecticut, California, Hawaii, Georgia, Iowa, Idaho, Louisiana, New Mexico, Kentucky, New Jersey, Utah, and New York. Together, the states accounted for about 31% of the US residents in 2022, including major racial and ethnic groups.
The study included adults aged 30 years and older, with denominators derived from the 2015–2022 American Community Survey (ACS). The team categorized participants as never married or never married. The ever-married group included married, separated, divorced, and widowed individuals. People who were cohabiting or in partnerships without legal marriage were included in the never-married group.
The researchers defined cancer sites using the International Classification of Diseases for Oncology, third edition (ICD-O-3) and the World Health Organization (WHERE) 2008 classifications. Additionally, they subtyped breast cancer based on estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) situation. They classified prostate cancers based on prostate-specific antigen (PSA) levels at diagnosis.
The researchers calculated incidence rates by age and used a regression model to calculate incidence rate ratios (IRR) comparing never-married to ever-married adults.
Marital status differences in cancer rates
In 2015-2022 PROPHET data represented over 62 million people per year. Overall, 19% were classified as unmarried, with higher rates among men (21.5%) than women (17%). Rates varied by race and ethnicity, highest among black women (34%) and men (35%) and lowest among white women (12%) and men (17%).
During the study period, 4.24 million cases of cancer were diagnosed, with 18% occurring in people who had never married. The never-married group had consistently higher incidence rates than ever-married adults, with IRR 1.68 in men and 1.85 in women.
Increased risks were observed in most cancer types and demographic groups, with IRR they range between 1.62 for white men and 1.96 for black men. It is worth noting that black men who were ever married had a lower incidence of cancer compared to white men of the same marital category.
Point-specific analyzes showed the strongest associations for cancers of the anus, cervix, esophagus, ovary, uterus, liver, lung, and colon (IRR2–5). In contrast, smaller differences were observed for thyroid, melanoma, prostate, testicular, kidney, and brain cancer (IRR1.2–1.6). Screening-sensitive cancers such as prostate (PSA1, IRR1.36) and thyroid cancer, showed comparatively modest associations.
Age-based analyzes showed widening inequalities with age, peaking at 70–74 years (IRR 1.99 for men. 2.23 in women). IRR were higher in adults aged ≥55 years (1.99) than in adults aged 30–54 years (1.49), suggesting cumulative lifetime effects, with women having consistently greater relative risks than men.
Across racial and ethnic groups, disparities were greatest among black men (IRR 1.96), followed by Hispanic men (1.82) and Whites and Asian/Pacific Islanders (both 1.62). Among women, IRR were consistently high (1.90–1.94) in all groups, indicating a similar pattern of increased risk.
Effects of marital status on cancer prevention
The study identifies marital status as an often overlooked social indicator of cancer disparities, with never-married adults having a consistently higher incidence of most cancers, especially in later life. Findings suggest that marital status reflects cumulative social, behavioral, and health care-related exposures beyond traditional risk factors, but legal marital status should not be interpreted as a direct proxy for social support or evidence of a causal effect.
Incorporating marital status into cancer surveillance and risk models could improve identification of high-risk populations and support targeted prevention strategies. In particular, stronger associations in HPV-related, tobacco, and reproductive cancers highlight actionable pathways for intervention. However, marital status was measured at diagnosis, and the dataset did not have individual-level information on income, education, parity, or health behaviors.
Future research should explore the underlying mechanisms and examine various relationship structures beyond legal marriage to better address cancer disparities, with the potential to inform more equitable and socially informed cancer prevention efforts.
