In sickness and in health

Marriage is, for many, a rite of passage in life. However, it may be that marriage is not the right passage – at least as far as your brain is concerned.

A study published last year suggests unexpected associations between marriage and the development of dementia.

Involving 24,000 participants, this US-based study followed adults aged 50 or older for up to 18 years.

It tracked different dementia types, including Alzheimer’s, Lewy Body and vascular dementia, to test whether marital status was associated with dementia risk.

It compared married participants with those who were widowed, divorced or never married and found that the incidence of dementia was highest among those who were married.

On the surface of things, you would imagine that marriage would protect those who share a marital bond. After all, loneliness is a known risk factor and having a partner should potentially guard against this.

Then, there is having someone else in your life who may encourage you to address health problems (for example, cardiovascular disease) that you might otherwise neglect and which can increase the rate of dementia.

Other studies have shown that those who are married have better overall health than those who are not (more so for men than women).

At-hand emotional support can also reduce the impact of depression and anxiety which have been linked with poor brain health. Also, there is the sense of purpose that comes with being in a long-term relationship, and this is an important ingredient for health in general and for reducing early mortality.

Of course, many of these benefits only arise if the marriage is functional and there is mutual support, and perhaps this explains some of the findings, but the magnitude of the effects leads me to believe there is more to it than this.

The risk reduction in dementia for divorced individuals was 34 per cent. Those who had never been married had a 40 per cent reduction and even widowed individuals on average had a 27 per cent reduced chance of developing dementia.

Another explanation for the findings is that those who are married are more likely to visit their doctors – due to the encouragement of their spouse – and therefore more likely to be diagnosed with dementia, consequently inflating the apparent risk. This is known as ascertainment bias: one of the many biases you need to pay attention to when interpreting data.

If it is a true finding, however, one possibility lies in the difference in social networks between married and non-married people. Those without a partner may have more need to speak with others on a regular basis and seek out more varied social contact.

We know that socialising is important for the brain – from its ability to buffer against loneliness, but also due to the cognitive ‘workout’ we get talking with others. Conversations are a great way of exercising the brain and the less predictable they are, the harder your brain must work.

This helps develop cognitive reserve: a protective factor against dementia. If marriage removes the compulsion to socialise with others, and especially if the conversations with your spouse are perennially familiar, this potential for building reserve is missed.

Now, I am not for one moment suggesting this study should encourage you to divorce your partner! It should make us think, however, about the importance of those wider social connections.

We benefit from social variety, and it is perhaps unwise to put all our eggs in the marital basket.

Women tend to do a better job at maintaining these extra-marital friendships, but is equally important that men proactively foster their mateship.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, available at bookstores and online. Visit yourbraininmind.com or uqp.com.au