In healthcare professions, it’s common knowledge that married people have better overall health and lower mortality than their unmarried peers. However, a new study published in AJPH indicates that adults who are cohabitating have midlife health outcomes that are similar to adults in formal marriages. So in terms of the benefits specific to marriage, we can probably strike “longer, healthier life” from the list.

The study in question used 10,000 subjects from the British national Child Development Study, a birth cohort study that includes all people born in Britain during one week in March 1958. Participants were able to select their partnership status as married, cohabitating, or single. Health was measured using blood and inflammatory biomarkers, as well as respiratory capacity. The researchers controlled for previous socioeconomic status, previous health status, educational attainment, income, employment, and other demographic variables.

The study’s results varied by gender. Among men, those who had never married/cohabitated displayed poorer overall health than men who were married during the observation period. By contrast, not marrying or cohabitating had less of a detrimental effect on women than on men. For women, the timing of the marriage mattered. Those who were married in their late 20s or early 30s had the overall best health, beating out both women who had married in their early 20s and women were never married/cohabitating.

The study found that changes in status had no obvious impact—the transitions from/to marriage and nonmarital cohabitation did not have a detrimental effect on health. There wasn’t an obvious difference in these biomarkers when participants divorced and then remarried or cohabitated; they looked the same as participants who remained married. For men who divorced in their late 30s and didn’t remarry, the risk of metabolic syndromes in midlife was reduced.

However, the researchers note that their study was long term, so the acute stress of major life events like divorce and remarriage may not have been captured in this data.

Overall, the researchers found that nonmarital cohabitation had similar effects as marriage with respect to midlife health. These results are in agreement with recent findings on self-reported health, but not with previous data on depression and self-reported physical health in the US. Some of these differences could be due to differences between the UK and the US or differences in the time period being studied. The researchers recommend further research to investigate the similarities and differences between health outcomes for marriage versus cohabitation.

In terms of generalizability, the researchers note that these findings may be specific to people born in or around the year 1958, as attitudes about partnership and marriage continue to change for younger generations. They expect that the association between partnership and health outcomes may be different in other age cohorts, especially younger ones, but they don’t have the data to know. Looking forward, perhaps we can expect to see more partnership/health outcome studies of millennials, a generation seemingly less interested in formal partnership than previous ones.