According to the latest review of the evidence, married folk have a much lower risk of developing dementia than lifelong singles.
Lifelong singles and widowers are at heightened risk of developing the disease, the findings indicate, although single status may no longer be quite the health hazard it once seemed to be, the researchers acknowledge.
The researchers revisited 15 studies investigating dementia and marital status. The investigation included more than 800,000 participants from Asia, North and South America, and Europe.
Married people accounted for between 28 and 80 per cent of people in the included studies; the widowed made up between around 8 and 48 per cent; the divorced between 0 and 16 per cent; and lifelong singletons between 0 and 32.5 per cent.
The researchers found that people who remained single throughout their life were 42 per cent more likely to develop dementia, after taking account of age and sex.
Part of this risk might be explained by poorer physical health among lifelong single people, the researchers suggest.
However, the most recent studies, which included people born after 1927, indicated a risk of 24 per cent, which suggests that this may have lessened over time, although it is not clear why, say the researchers.
The widowed were 20 per cent more likely to develop dementia than married people, although the strength of this association was somewhat weakened when educational attainment was factored in. Bereavement is likely to boost stress levels, which have been associated with impaired nerve signalling and cognitive abilities, the researchers note.
No such associations were found for those who had divorced their partners, although this may partly be down to the smaller numbers of people of this status included in the studies, the researchers point out.
The lower risk of dementia among married people persisted even after more detailed analysis, which, the researchers suggest, reflects “the robustness of the findings”.
“Marriage may help both partners to have healthier lifestyles, including exercising more, eating a healthy diet, and smoking and drinking less, all of which have been associated with lower risk of dementia,” the researchers explain.
“Couples may also have more opportunities for social engagement than single people – a factor that has been linked to better health and lower dementia risk,” they suggest.
Read the full study.
Why do you think married people seem to have a lower risk of dementia?