Married individuals tend to live longer, but what about cohabiters? Using data from the Swedish registry, Jesper Lindmarker, Martin Kolk and Sven Drefahl find that cohabitation reduces the risk of mortality compared to being unpartnered, even if less so than marriage. The longevity benefits of cohabitation, however, vary by age and marital history.
Why do some people live longer than others? This question has long motivated research in public health, demography, and sociology. One consistent finding is that married individuals tend to outlive those who remain single, divorced, or widowed (Rendall et al. 2011). However, as family structures evolve – with non-marital cohabitation becoming increasingly common worldwide, and most notably in Sweden (Ohlsson-Wijk, Turunen, and Andersson 2020) – the question arises: does cohabitation offer the same longevity benefits as marriage, or is there something unique about marital unions?
The link between marriage and longevity is based on well-established social and economic advantages (Carr and Springer 2010). Given that long-term cohabitation is more commonly accepted and often resembles marriage in daily life, it is essential to determine if these protective advantages also apply to non-marital relationships.
In a recent study (Lindmarker, Kolk, and Drefahl 2025), we examined Swedish register data (2012–2017) to assess the effects of cohabitation and marriage on mortality throughout life. The findings indicate that cohabitation is less protective than marriage, but its effects differ based on age and previous marital status.
Why would a partner extend life?
The link between longevity and partnership status arises from both selection processes and protective factors. Healthier individuals are more likely to partner and remain with a partner, suggesting that part of the marriage advantage is due to selection effects (Lillard and Panis 1996). Beyond selection, partnerships confer substantial protective benefits. Social support plays a crucial role: a partner not only provides companionship, but also monitors health, encourages adherence to medications, and offers emotional comfort that counteracts the negative effects of stress. This effect is especially apparent among men, whose health behaviors are most positively affected by their partners (Umberson 1987).
Economic stability is another significant advantage. By pooling resources, couples experience reduced financial stress and improved access to healthcare. In addition, partnership tends to promote healthy habits, from maintaining regular meals and routines to avoiding risky behaviors. Caregiving and companionship provided by spouses are particularly critical in later life, when support can mitigate the risks associated with social isolation.
Cohabitation and mortality: divergent risks by age and marital history
Our study shows that married individuals generally experience the lowest risk of mortality. Cohabiters have lower mortality than unpartnered individuals, including singles, divorcees, or widow(er)s. However, their death risks vary significantly by marital history and age.
• Never-married cohabiters: At ages 30–49, never-married cohabiters have mortality risks comparable to those of married individuals. This suggests that in early adulthood, cohabitation provides protective benefits similar to marriage. However, in older age groups (50+), never-married cohabiters begin to experience higher mortality risks than married individuals. This may be due to both selection effects, as healthier individuals tend to transition into marriage, and the reduced long-term benefits of cohabitation relative to marriage.
• Divorced/Widowed cohabiters: For those who cohabit after a previous marriage, the pattern is reversed. In younger age groups, divorced or widowed cohabiters face significantly higher mortality risks than their married counterparts, likely reflecting negative selection, where union dissolution at younger ages is linked to poorer health and socioeconomic challenges. However, in older age groups, excess mortality among divorced cohabiters decreases, probably because of the increasing prevalence, in this group, of those who re-partner later in life after long marriages, carrying forward financial, social, and health advantages from their previous unions. This “double advantage” from both past stable marriages and new partnerships helps reduce the risk of mortality compared to younger divorced cohabiters.
Why do these patterns emerge?
Several factors help explain the longevity differences between cohabitation and marriage. Selection effects matter: long-term cohabiters may differ from married individuals in ways that influence health and longevity. Social support is key: while cohabitation offers companionship, it may not always provide the same level of long-term caregiving as marriage, especially later in life. Economic factors also play a role, since marriage traditionally provides greater financial security and better access to healthcare. Finally, the cumulative benefits of marriage, including reinforced healthy behaviors, legal protections, and social support, appear to confer an enduring advantage in promoting longevity.
Although cohabitation offers significant health benefits, it does not fully replicate the long-term advantages of marriage, but it is still unclear whether these differences arise from selection processes, socio-economic factors, or the distinct ways in which marriage and cohabitation shape life outcomes.
References
Carr, Deborah, and Kristen W. Springer. 2010. “Advances in Families and Health Research in the 21st Century.” Journal of Marriage and the Family. https://doi.org/10.1111/j.1741-3737.2010.00728.x.
Lillard, Lee A., and Constantijn W. A. Panis. 1996. “Marital Status and Mortality: The Role of Health.” Demography. https://doi.org/https://doi-org.ezp.sub.su.se/10.2307/2061764.
Lindmarker, Jesper, Martin Kolk, and Sven Drefahl. 2025. “Cohabitation and Mortality Across the Life Course: A Longitudinal Cohort Study with Swedish Register-Based Sibling Comparisons.” European Journal of Population 41 (1): 2. https://doi.org/10.1007/s10680-024-09722-6.
Ohlsson-Wijk, Sofi, Jani Turunen, and Gunnar Andersson. 2020. “Family Forerunners? An Overview of Family Demographic Change in Sweden.” In International Handbook on the Demography of Marriage and the Family, edited by D. Nicole Farris and A. J. J. Bourque, 7:65–77. Cham: Springer International Publishing. https://doi.org/10.1007/978-3-030-35079-6_5.
Rendall, Michael S., Margaret M. Weden, Melissa M. Favreault, and Hilary Waldron. 2011. “The Protective Effect of Marriage for Survival: A Review and Update.” Demography 48 (2): 481–506. https://doi.org/10.1007/s13524-011-0032-5.
Umberson, Debra. 1987. “Family Status and Health Behaviors: Social Control as a Dimension of Social Integration.” Journal of Health and Social Behavior 28 (3): 306–19. https://doi.org/10.2307/2136848.