For years, studies have linked marriage with happiness among heterosexual couples.
A new study now shows that the benefits of marriage extend to lesbian, gay, bisexual or transgender (LGBT) couples as well.
In the study, published in The Gerontologist journal, LGBT participants who were married reported better physical and mental health, more social support and greater financial resources than those who were single.
For the research Jayn Goldsen, from the University of Washington, and her colleagues used survey data from more than 1 800 LGBT people, aged 50 and older, in locations where gay marriage was already legal in the US in 2014.
About a quarter were married, another quarter were in a committed relationship and half were single.
Married respondents had spent an average of 23 years together, while those in committed relationships had been together for an average of 16 years. Among the participants, more women were married than men.
Researchers found that participants in a relationship, whether married or in a long-term partnership, showed better health outcomes than those who were single.
But those who were married fared even better, both socially and financially, than couples in unmarried, long-term partnerships.
Single LGBT adults were more likely to have a disability; to report lower physical, psychological, social and environmental quality of life; and to have experienced the death of a partner, especially among men.