The Effects of Marriage on Health: A Synthesis of Recent Research Evidence. Research Brief. What Is Currently Known?

07/01/2007

Effects on Health Behaviors. Marriage may influence health through its effect on behaviors such as alcohol consumption, drug use, cigarette smoking, diet, and exercise. Recent research suggests that marriage has significant effects on the health behaviors of both men and women, but the pattern is mixed — marriage is associated with healthier behaviors in some cases and less healthy behaviors in others. Studies consistently indicate that marriage reduces heavy drinking and overall alcohol consumption, and that effects are similar for young men and young women, and for both African Americans and whites.(8, 9, 10, 11)  Although the research is less extensive, marriage is also associated with reduced marijuana use for young men, but less so for women.(8, 11)  Less is known about the effects of marriage on the substance use of older adults. Studies of marriage and smoking reveal no consistent pattern of results, suggesting that marriage may have little or no influence on this behavior.(8, 11, 12, 13)

In contrast to studies of alcohol and drug use, studies of the effect of marriage on weight and physical activity suggest that marriage may have negative effects on healthy behaviors and may encourage a more sedentary lifestyle. Several rigorous studies find that marriage leads to modest weight increases for both men and women — typically averaging less than five pounds.(14, 15, 16, 17, 13, 12)  The research on the effects of marriage on physical activity is less conclusive because it is not based on longitudinal analysis and does not fully adjust for differences between those who marry and those who do not. The evidence that is available suggests marriage may lead to reductions in physical activity, particularly for men.(18)

For certain health behaviors — in particular, substance use among younger adults and weight gain among all adults — the influence of marriage has been well studied and is well understood. For other behaviors, less is known and additional research is needed before stronger conclusions can be drawn. One useful area for future research is to examine the effects of marriage on the alcohol use of older adults to determine whether the effects observed for young adults exist in older populations. Additional research using longitudinal data is also needed to examine the effects of marriage on physical activity to determine whether the relationship between marriage and physical activity observed in cross-sectional analyses remains when more rigorous estimation techniques are used.

Effects on Health Care Access, Use, and Costs.  Marriage may influence physical health through its effects on health care access and use. Studies of the link between marriage and health insurance suggest that — by offering access to coverage through a spouse's policy — marriage increases the likelihood of having insurance and reduces the likelihood of becoming uninsured after a job loss or other major life event.(19)  This effect is larger for women. Recent research also finds a link between marriage and health care use. Marriage is associated with shorter average hospital stays, fewer doctor visits, and reduced risk of nursing home admission.(20, 21, 22)  Limited evidence also suggests that marriage may increase the use of preventive care such as cancer screenings.(12)

Because of its effects on health care use, marriage is also associated with lower health care costs among older adults. For example, studies show that, because marriage reduces the risk of nursing home admission, marriage may also lead to reduced nursing home costs.(22)  The effect of marriage in shortening hospital stays may also lead to reductions in health care costs. Research indicates that the effect of marriage on health care costs exists independent of the effect of marriage on physical health.(22)  Specifically, many married people rely on their spouses for informal care, and thus require fewer long hospital stays and nursing home admissions, resulting in lower health care costs — even if married and unmarried older adults are equally likely to get sick.(20, 21)  These studies find that wives are especially likely to provide informal care for their husbands at home, so the effect of marriage on health care costs may be larger for men.

The link between marriage and health care costs needs further study, because most previous research provides only indirect evidence based on examination of effects on high-cost health services, such as nursing home care. Other outcomes ripe for future research include quality of care, use of prescription medications, receipt of high-tech exams and treatments, patient adherence to prescribed treatment regimens, and use of preventive health services other than cancer screenings.

Effects on Mental Health.  Marriage may affect many aspects of mental health. This review focuses on the prevalence of depressive symptoms. The most recent rigorous research suggests that marriage reduces depressive symptoms for both men and women.(23, 24, 25, 26)  In particular, these studies find that getting married decreases depressive symptoms, while getting divorced increases them. Research has also documented that increases in depressive symptoms after divorce are long-lasting and that the prevalence of these symptoms remains elevated years after the marital breakup.(27, 28)  In addition, studies comparing the mental health of stably married adults to those who remain unmarried find that those who are stably married have fewer depressive symptoms (and smaller increases in these symptoms as they grow older), even after controlling for baseline mental health.(23, 25, 26)

Although research consistently shows that being married reduces depression, the existing evidence has limitations that future research should address. In particular, the most rigorous research typically estimates the effect of marriage and marital transitions by comparing the prevalence of depressive symptoms in the period just before a marital transition to the prevalence in the period just after the transition. This method adjusts for background differences between those who marry and those who do not. However, it may introduce other sources of bias into the estimates, and the direction of this bias is uncertain.

For example, people may experience fewer depressive symptoms in the period leading up to marriage in anticipation of this transition. Similarly, people may experience more depressive symptoms in the period leading up to a divorce, as the quality of their marriage declines. If so, comparing someone's depressive symptoms during the period just before a marital transition to the period immediately after may underestimate the effect of this transition. Conversely, if depressive symptoms are reduced for only a short time after marriage or are elevated for only a short time after a marital dissolution before returning to their pre-transition levels, comparisons of depressive symptoms just before and just after the transition would overestimate the long-term effect. To address these limitations and to obtain a more precise understanding of the relationship between marriage and depression, longitudinal data sets are needed that offer more detailed mental health histories and more information on changes in mental health status than are currently available.

Effects on Physical Health and Longevity.  Many studies have documented that people who marry live longer and enjoy better physical health than those who do not marry.(29, 30)  However, methodological issues require caution in interpreting this pattern, because most of the research in this area relies on descriptive methods that do not adequately control for the possible selection of healthier people into marriage. Although central to the overall assessment of the link between marriage and health, rigorous research evidence concerning the effect of marriage on specific physical health outcomes is limited, and few solid conclusions can be drawn.

The rigorous research currently available provides limited evidence of an effect of marriage on physical health. Recent research finds a significant positive effect of marriage on how men rate their overall physical health status; however, it finds no such effect for women.(30)  Researchers find a positive effect on women's physical health, as measured by the prevalence of specific health conditions and illnesses.(31)  However, no recent rigorous studies based on U.S. samples have examined whether a similar marriage effect on the frequency of health conditions or illnesses exists among men. Similarly, little evidence exists on the links between marriage and specific health conditions or diseases. One exception is a recent study that suggests a possible link between marriage and the risk of cardiovascular disease for women; however, the study finds no such effect for men.(32)  Overall, the existing research evidence on the links between marriage and physical health is limited to a narrow range of health measures and does not offer a complete picture of the influence of marriage on physical health.

Many studies have pointed to a strong relationship between marriage and longevity,(33, 29, 34)  but this research also has limitations. In particular, these studies are typically limited to simple descriptive comparisons of married and unmarried adults that do not adequately distinguish the effect of marriage from the possible effects of healthier people selecting into marriage. As noted, the most reliable studies of links between marriage and health examine measures directly before and after marital transitions. However, because longevity is determined only at the end of life, it is not possible to observe how a marital transition changes longevity. Some researchers have attempted to address selection using other statistical techniques,(5)  but these studies provide less convincing evidence than do studies of marital transitions. For this reason, the strongest evidence of a positive effect of marriage on longevity comes more from the robustness of this relationship across many studies than from the particular strengths of any single study.

A more definitive test of the effect of marriage on physical health and longevity will require very long-term longitudinal data that afford the opportunity to control for differences in initial health status measured before sample members begin to marry. With data of this type, researchers can examine how differing marital histories affect physical health, controlling for any initial health differences that exist between those who marry and remain married and those who do not.

Intergenerational Health Effects. An emerging literature on the possible intergenerational health effects of marriage suggests that marriage also has potential long-term consequences for the physical health of a couple's children. In particular, studies show that growing up with married parents is associated with better physical health in adulthood and increased longevity.(35, 36, 37)  Research suggests that such intergenerational health effects are especially strong for men and operate equally for African American and white men.(38, 39, 40)  There is less evidence examining possible differences in this relationship for African American and white women.

There are many possible reasons why parental marital status may have long-term health consequences for children. However, existing research provides limited evidence on the pathways by which childhood family structure affects adult physical health and longevity. Several studies suggest that the effects work mostly through the role of childhood family structure in shaping children's future socioeconomic attainment, and through adult health risk behaviors, such as smoking and heavy drinking.(35, 39)  On average, children raised in two-parent families obtain more education and exhibit healthier adult behaviors than children from other types of families. These differences, in turn, have consequences for adult health and longevity.

Research on intergenerational health effects has focused on trends for people born in the late 19th and early 20th centuries, a period when patterns of marriage, divorce, and single parenthood were much different from today. It is possible that the apparent benefits of marriage for children's health have weakened as single parenthood and divorce have become more common and less stigmatizing. In addition, much of the research is limited to data for small nonrepresentative samples. The available nationally representative evidence is based on data sets that began tracking sample members as adults, which limits the ability to control for differences in the background characteristics of those who grew up in a two-parent family and those who did not.

Future research is needed to

  1. Replicate the results of existing research with nationally representative data following sample members from childhood into adulthood,
  2. Distinguish more clearly the effect of parental marital status from the effects of other related family characteristics,
  3. Identify more precise mechanisms by which childhood family structure might influence adult physical health, and
  4. Examine whether the relationships observed in earlier generations also apply to a younger cohort of children coming of age in a period when divorce and single parenthood are increasingly common.

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