In Sickness and in Health: Marriage's Impact on Dementia

John Watson

Disclosures

January 10, 2018

Studying Dementia Through Marital Status

It is currently estimated that more than 48 million people globally have dementia, a prevalence rate that is expected to nearly triple by 2050.[1]

Andrew Sommerlad, MBBS, MSc

According to researchers behind a meta-analysis recently published in the Journal of Neurology, Neurosurgery, and Psychiatry,[2] this has increased the pressure to identify any modifiable risk factors that could potentially intervene in this devastating neurologic illness. With this goal in mind, they surveyed data from 15 observational studies and over 800,000 participants to assess the impact of one such factor: marital status.

Medscape spoke with the study's lead author, Andrew Sommerlad, MBBS, MSc, a geriatric psychiatrist and Wellcome Trust research fellow at University College London, United Kingdom, to learn more about what they found and its possible implications in daily practice.

Why Marriage?

Medscape: What was the underlying science, if any, on the link between marriage and dementia that led you to conduct this analysis?

Dr Sommerlad: We are interested in identifying factors that may reduce or delay dementia, because changes in dementia incidence rates over time indicate that the condition may be partly preventable.

We were aware of the research literature showing that being married is associated with a range of health benefits, and wondered whether the potential health benefits of married life may extend to lower dementia risk.

Medscape: What are the major take-away lessons from you and your coauthors' meta-analysis?

Dr Sommerlad: We pooled the results from the highest-quality research studies examining the links between marriage and dementia, and found that single people had a 42% higher risk for dementia and that widowed people had 20% higher risk than married people. There was no difference between divorced and married people.

Medscape: Presumably, the cause of the reduction in the risk for dementia is not marriage in and of itself. What do you think the underlying factors might be for how marriage potentially affects dementia rates?

Dr Sommerlad: We do not think that it is marriage itself that reduces peoples' risk for dementia. Our research instead suggests that the possible protective effect is linked to various lifestyle factors that are known to accompany marriage, such as living a generally healthier lifestyle and having more social stimulation as a result of living with a spouse or partner.

Studies found that worse physical health in part accounts for the higher risk in single people, and that less education partly accounts for the risk in widowed people. This suggests that unmarried people may be able to reduce their dementia risk by engaging in keeping an active body and mind.

The Benefits of Marriage, or Harms of Widowhood?

Medscape: How we define marriage and what it entails obviously varies considerably across cultures. As such, would you expect these conclusions to be applicable only in the studies from which you obtained data?

Dr Sommerlad: The 15 studies we included came from Europe, North and South America, and Asia. We compared the findings from studies in lower- and higher-income countries and found no differences, suggesting that these findings are consistent across different cultures.

Medscape: One way to view these data are that marriage prevents dementia. However, as you and you coauthors indicate in your conclusion, there could be a different trend at work here, in that the loss of a spouse may increase the risk for dementia.

In that sense, it may not be the richness of the bond of marriage that's sustaining cognition, so much as the severing of that bond is leading to adverse outcomes. Can you speak to that possible association? Is that a fair assessment?

Dr Sommerlad: The risk for dementia was higher among widowed people than among married people, so despite having previously been married (for many decades, in most cases), the end of their marriage seemed to increase their dementia risk.

This may be because they lost the social and cognitive stimulation of having a spouse or began to take less care of their physical health once bereaved. However, an alternative explanation is that the stress of bereavement could have precipitated the onset of dementia, because studies have shown that stress can have a detrimental effect.

We are interested in examining this further and would need to look at the time between bereavement and dementia onset. If this is a sudden effect, then it is more likely to be related to the distress caused by losing a spouse.

Medscape: What does the literature show about the other potential health values of marriage, if any? Or conversely, are there known health disadvantages to marriage that would offset them?

Dr Sommerlad: Other studies have shown a range of health benefits associated with marriage. Married people with cancer have a better prognosis, older adults who are widowed have higher rates of disability, and there is a longer life expectancy in married people—and this is more true for married men than women.

We know of no adverse risks associated with marriage. However, it may be that the health differences between married and unmarried people are decreasing over time. In our study, single people born during the first quarter of the 20th century had a 40% higher risk than married people, whereas later studies only found a 24% higher risk. So it may also be important to consider.

As being unmarried becomes more of a social norm, it is likely that lifestyle differences between married and unmarried people are lessening, so the picture is unlikely to be static.

Practical Applications

Medscape: How do you recommend clinicians practically apply these findings?

Dr Sommerlad: Doctors should be aware of this increased risk and have a higher level of suspicion of dementia in unmarried people. Diagnosis of dementia is more difficult in people who attend clinics alone, because there may be no one to provide collateral information, but steps should be taken to ensure thorough assessment in those who may have the condition.

Medscape: The link between social interaction and sustained cognition is clearly established in multiple settings. Given that, how do you think we should reconsider our approach to geriatric care? For example, shared living situations are sometimes looked down upon or avoided by the elderly population, but perhaps they should be promoted more for their potential cognitive benefits.

Dr Sommerlad: We agree that this should be a priority area in the future. Loneliness is common in older people who do not have dementia, so for those who have the condition and therefore have more difficulty forging social connections, isolation can be a major problem. There is likely to be a drive toward use of technological solutions for care provision in older people, but these should not replace social contact.

However, many are accustomed to their lifestyles and are reluctant to try new social settings, so a challenge is to design such environments that are acceptable to older people.

Medscape: What questions still need to be answered on this topic?

Dr Sommerlad: Future research should examine this link in more detail, in particular considering the contribution of social contact and health behaviors, and whether the length of time of widowhood is important.

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