Marriage and health

Beyond marriage, social relationships more broadly have a powerful impact on health. A meta-analysis of 148 studies found that those with stronger social relationships had a 50% lower risk of all-cause mortality.^[4] Conversely, loneliness is associated with increased risk for cardiovascular disease, and all-cause mortality.^[5] Little work has directly compared the health impacts of marriage compared to those of non-romantic relationships, such as connections with friends or colleagues.^[1] However, there are several reasons why marriage may exert a greater health impact than other relationships, even other cohabiting relationships: married couples spend time together during a wide variety of activities, such as eating, leisure, housekeeping, child-care and sleep.^[1] Spouses also share resources and investments such as joint finances or home-ownership. Relative to other relationships, the increased interdependence of marriage serves as a source for more intense support.^[1]

Romantic couples who live together, but are unmarried, may represent a middle ground in health benefits between those who are married, and those who self-identify as single.^[6] However, people live together without getting married for many different reasons; cohabitation may serve as a prelude to marriage. Selection factors of race, ethnicity, and social-economic status predispose certain groups to cohabit unmarried, and these factors also affect the health benefits of marriage and cohabitation.^[1]

Most research on marriage and health has studied heterosexual couples. Same-sex and opposite-sex couples share many similarities. Both begin marriage with high levels of relationship satisfaction, followed by later declines, and both argue with similar frequency about similar issues.^[7][8]

However, same-sex couples resolve conflicts more effectively, and distribute household labor more fairly compared to their heterosexual counterparts.^[7][8] Same-sex marriage is or was illegal in many countries, including many parts of the United States (where much research on marriage and health has been conducted) until 2015.^[1] In these regions same-sex couples are not granted the institutional protections of marriage or its accompanying legal barriers to relationship dissolution.^[9] Moreover, same-sex couples are more likely to experience discrimination against their sexual orientation, contributing to problems with mental health and relationship quality.^[10]

The health-protective effect of marriage is stronger for men than women.^[2][3] Marital status — the simple fact of being married — confers more health benefits to men than women.^[2] Women's health is more strongly impacted than men's by marital conflict or satisfaction, such that unhappily married women do not enjoy better health relative to their single counterparts.^[2][3][11] Laboratory studies indicate that women have stronger physiological reactions than men in response to marital conflict.^[2][3]

These gender differences may be partially due to men's and women's relative status in a relationship.^[3] Research in humans and animals suggests subordinate status is linked to greater physiological reactions to social stress.^[3] Indeed, subordinate spouses show greater physiological reactions to arguments with their partner.^[12] Both husbands and wives show stronger physiological reactions to arguments when making demands for change from their partner.^[13][14] Women's heightened physiological reactions to marital conflict may be due to their relative subordinate position in marriage.^[3]

Research on the links between marriage and health has measured diverse outcomes. These are broadly categorized as clinical endpoints, surrogate endpoints, and biological mediators.^[15] Clinical endpoints are variables which affect how people feel, function, and survive.^[15] They are recognized as important outcomes by health care providers and patients, for instance being hospitalized, or having a heart-attack.^[15]

Surrogate endpoints and biological mediators are types of biomarkers—objective indicators of normal or pathological physiological processes.^[15] Surrogate endpoints serve to substitute for clinical endpoints. They are expected to predict clinical endpoints, based on scientific evidence.^[15] For example, elevated blood pressure has been found to predict cardiovascular disease.^[16]

Biological mediators reflect short-term sources of stress which affect health outcomes through repeated or persistent activation.^[17] These processes do not have a sufficient evidence base linking them to clinical endpoints in order be elevated to the class of surrogate endpoints.^[1] Examples include changes in hormone levels, or immune measures.

The health benefits of marriage are a result of both selection and protection effects.^[18] People with better health, more resources, and less stress are more likely to marry, and marriage brings resources, and social support.^[18] The health benefits of marriage persist even after controlling for selection effects, indicating that being married is protective of health.^[19]

Research on marriage and health is part of the broader study of the benefits of social relationships. Social ties provide people with a sense of identity, purpose, belonging and support.^[20] Two main models describe how social support influences health.

The main-effects model proposes that social support is good for one's health, regardless of whether or not one is under stress.^[21] The stress-buffering model proposes that social support acts as a buffer against the negative effects of stress occurring outside the relationship.^[21] Both models have received empirical support, depending on how social support is conceptualized and measured.^[21] Marriage should be a strong source of social support in both models.^[1]

There are several interesting social norms between couples that are relevant towards forming health-related habits. Couples have a higher chance of accomplishing a goal when they collaborate, as opposed to achieving the same goal as individuals.^[22][23] In addition, couples' habits play an important role in influencing the health habits of their children. As a result, shared activities among couples can help develop stronger relationships that can lead to other health and long-term benefits. There are several interesting social norms between couples that are relevant towards forming health-related habits. Examples include:

• Eating Dynamics: Couples like to eat together, and although they perform divergent activities during the day, they often 'come together and look forward to dinner'.^[24] In addition, couples have an affinity to grocery-shop together, which is an important opportunity to make household decisions towards healthy eating.
• Reduced Exercise Patterns: Time constraints and other obligations often deter couples from regularly exercising. In particular, their stable relationships often propel them to "let go" and be less concerned about their physique.^[25] In societies with strong conformist dynamics, some partners are less likely to exercise unless they go with a companion.^[26]
• Re-evaluation of Attitudes Towards Health: As couples adopt to new lifestyles, they concurrently re-assess their current attitudes towards health. In this crucial phase, partners are more likely to integrate new knowledge and practical skills towards a health-related lifestyles.^[27]
• Encouragement and Praise vs. Criticism and Nagging: Verbal support from a spouse, such as encouragement and praise, helps improve physical activity achievement,^[28] whereas support disguised as "criticism" and nagging are often detrimental.^[26]
• Comparison Anxiety: Anecdotal accounts provide hints on the detrimental effects of comparing exercise progress. Couples may have different rates of progress, and for some partners, comparisons could lead to discouragement. A more collaborative approach towards a unified goal has been found to be more beneficial.^[23]

There exists several studies^[24][29][30] specifically examining the effect of spousal engagement on exercise program adherence. For example, one study examined healthy couples' behavior based on a 12-month fitness program where researchers tracked the behaviors between 30 married individuals vs. 32 married pairs- that is, people who had joined the exercise program together (as pairs) or by themselves (individually).^[29] Their results reveal statistically significant differences:  at the end of the study, 6.3% of the married-pairs had dropped out of the program, compared to 43% of the married individuals. These findings are consistent with previous research,^[24][30] and they point to the notion that social support in the form of "spousal participation" exerts beneficial effect on adherence towards fitness programs, or in general, most types of health-related joint endeavor.

Consistently, studies have shown that couples with marital status have shown to have lower rates of mental health disorders than their counterparts being divorced or never married.^[31] Marriage has been seen to be beneficial to meeting the social and intimacy needs of individuals as well as increasing their sense of social status among their peers.^[32]