Married individuals had lower levels of the stress hormone cortisol than those who never married or were previously married, found a Carnegie Mellon University study.
Studies have suggested that married people are healthier than those who are single, divorced or widowed. This study provides the first biological evidence to explain how marriage impacts health.
The researchers found that married individuals had lower levels of the stress hormone cortisol than those who never married or were previously married. These findings support the belief that unmarried people face more psychological stress than married individuals. Prolonged stress is associated with increased levels of cortisol which can interfere with the body's ability to regulate inflammation, which in turn promotes the development and progression of many diseases.
"It's is exciting to discover a physiological pathway that may explain how relationships influence health and disease," said Brian Chin, a PhD student in the Dietrich College of Humanities and Social Sciences' department of psychology.
Over three non-consecutive days, the researchers collected saliva samples from 572 healthy adults aged 21-55. Multiple samples were taken during each 24-hour period and tested for cortisol.
The results showed that the married participants had lower cortisol levels than the never married or previously married people across the three-day period. The researchers also compared each person's daily cortisol rhythm – typically, cortisol levels peak when a person wakes up and decline during the day. Those who were married showed a faster decline, a pattern that has been associated with less heart disease, and longer survival among cancer patients.
"These data provide important insight into the way in which our intimate social relationships can get under the skin to influence our health," said laboratory director and co-author Sheldon Cohen, the Robert E Doherty University professor of psychology.
Abstract
Married people tend to be healthier than both the previously (bereaved, divorced, and separated) and never married, but the mechanisms through which this occurs remain unclear. To this end, research has increasingly focused on how psychological stress experienced by unmarried versus married individuals may differentially impact physiological systems related to health. One key system that is modulated by stress is the hypothalamic-pituitary-adrenal (HPA) axis, of which cortisol is a key hormonal product. Increased cortisol production and disruption of cortisol’s daily rhythm have been linked to poorer health outcomes. This study examined the association between current marital status and these two indices of cortisol in a community sample of 572 healthy men and women aged 21–55. It also tested whether marriage buffers against the effect of stress (perceived stress by marital status interaction) on cortisol production. Participants provided salivary cortisol samples during waking hours on three nonconsecutive separate days to calculate diurnal cortisol levels and slopes. Married individuals had lower cortisol levels than either their never married or previously married counterparts. Differences in cortisol levels were due at least in part to currently married individuals having a more rapid decline in cortisol through the afternoon hours compared to individuals who were never married (but not those who were previously married). Furthermore, there was an interaction between perceived stress and marital status in predicting cortisol levels. Specifically, higher stress was associated with higher cortisol levels for previously married individuals but not for the married or never married. The results of this study support cortisol as one candidate mechanism accounting for the association of marital status and health.
Authors
Brian Chin, Michael Lm Murphy, Denise Janicki-Deverts, Sheldon Cohen
[link url="http://www.cmu.edu/news/stories/archives/2017/february/marriage-good-for-health.html"]Carnegie Mellon University material[/link]
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