A major US analysis links never-married status to higher cancer incidence across most cancers, revealing how social and behavioral factors may shape risk across the life course.
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 marital status may be associated with differences in cancer risk in the United States (U.S.). Using population-level data, researchers found that never-married adults, particularly Black men, had markedly higher cancer incidence across most cancers.
Risk was 68% higher in men and 83% higher in women compared with ever-married individuals, with the strongest associations seen in those aged ≥55 years.
The findings suggest cumulative behavioral and social influences, though some observed differences may also reflect selection into marriage, with important implications for cancer prevention and public health strategies, especially in aging populations and underserved communities.
Marriage, Social Support, and Cancer Risk Background
Marriage has been linked to improved health outcomes, including longer survival, lower morbidity, and better self-reported health, largely due to stronger social support, healthier behavioral habits, and greater economic stability. By middle age, unmarried individuals are also more likely to experience adverse physiological changes, characterized by inflammation and metabolic dysregulation.
Married individuals 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Existing evidence is limited by outdated, small, or region-specific studies that often rely on clinical or healthcare-based samples and are prone to bias. Moreover, changing social norms and risk factor patterns highlight the need for updated population-level research.
U.S. Cancer Incidence Study Design
In the present study, researchers assessed cancer incidence by marital status, cancer site, age, sex, and race/ethnicity. They analyzed data from the Surveillance, Epidemiology, and End Results (SEER) program covering 12 U.S. states.
These included Connecticut, California, Hawaii, Georgia, Iowa, Idaho, Louisiana, New Mexico, Kentucky, New Jersey, Utah, and New York. Together, the states represented about 31% of U.S. 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 ever-married or never-married. The ever-married group comprised married, divorced, separated, and widowed individuals. People who were cohabiting or in partnerships without legal marriage were included in the never-married group.
The investigators defined cancer sites using the International Classification of Diseases for Oncology, third edition (ICD-O-3) and World Health Organization (WHO) 2008 classifications. Additionally, they determined breast cancer subtype based on estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) status. They classified prostate cancers based on prostate-specific antigen (PSA) levels at diagnosis.
The researchers calculated age-specific incidence rates and used a regression model to estimate incidence rate ratios (IRRs) comparing never-married with ever-married adults.
Marital Status Differences in Cancer Rates
The 2015-2022 SEER data represented over 62 million people annually. Overall, 19% were classified as never-married, with higher proportions in men (21.5%) than women (17%). Rates varied by race and ethnicity, highest in Black women (34%) and men (35%), and lowest among White women (12%) and men (17%).
During the study period, 4.24 million cancer cases were diagnosed, with 18% occurring in never-married individuals. The never-married group consistently showed higher incidence rates than ever-married adults, with IRRs of 1.68 in men and 1.85 in women.
Elevated risks were observed across most cancer types and demographic groups, with IRRs ranging between 1.62 for White men and 1.96 for Black men. Notably, ever-married Black men showed lower cancer incidence compared to White men in the same marital category.
Site-specific analyses showed the strongest associations for anal, cervical, esophageal, ovarian, uterine, liver, lung, and colorectal cancers (IRRs, 2–5). In contrast, smaller differences were observed for thyroid, melanoma, prostate, testicular, kidney, and brain cancers (IRRs, 1.2–1.6). Screening-sensitive cancers, such as prostate (PSA1, IRR, 1.36) and thyroid cancer, showed comparatively modest associations.
Age-stratified analyses showed widening disparities with age, peaking at 70–74 years (IRR 1.99 in men; 2.23 in women). IRRs were higher in adults aged ≥55 years (1.99) than those aged 30–54 years (1.49), suggesting cumulative life-course effects, with women showing consistently greater relative risks than men.
Across racial and ethnic groups, disparities were highest among Black men (IRR 1.96), followed by Hispanic men (1.82), and White and Asian/Pacific Islander men (both 1.62). Among women, IRRs were consistently high (1.90–1.94) across all groups, indicating a similar pattern of elevated risk.
Marital Status Implications for Cancer Prevention
The study identifies marital status as an often overlooked social indicator of cancer disparities, with never-married adults showing consistently higher incidence across most cancers, especially in later life. The findings suggest that marital status reflects cumulative social, behavioral, and healthcare-related exposures beyond traditional risk factors, but legal marital status should not be interpreted as a direct proxy for social support or as proof 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. Notably, stronger associations in HPV-related, tobacco-related, and reproductive cancers highlight actionable pathways for intervention. However, marital status was measured at diagnosis, and the dataset lacked individual-level information on income, education, parity, or health behaviors.
Future research should explore underlying mechanisms and consider diverse relationship structures beyond legal marriage to better address cancer disparities, with the potential to inform more equitable and socially informed cancer prevention efforts.
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