Earlier studies suggest that being married in later life protects against dementia and that being single in old age increases the risk of dementia. A new study examined midlife marital status trajectories and their association with dementia and mild cognitive impairment (MCI) at ages 70 plus.
Scientists looked at different types of marital status in people over 24 years. The findings indicate that the group who remained wed continuously during the study had the lowest incidence of dementia. The highest incidence was found in divorced and single people.
Asta Håberg, a doctor at St. Olav’s Hospital and a professor at NTNU, said, “Exactly what causes dementia is a mystery. This survey indicates that being married and a lower risk of dementia are linked, but we don’t know why.”
“One theory has been that married people live healthier lives and that this explains differences in the risk of various diseases. In this survey, we found no support for health differences between married and unmarried people explaining the difference in dementia risk.”
About 150 000 residents of Nord-Trndelag participated in the HUNT study and agreed to allow scientists access to their health information. Using this information, the scientists looked into the link between the prevalence of dementia and other risk factors for disease, including smoking, high blood pressure, obesity, physical inactivity, diabetes, psychological issues, and having close relationships.
These factors indicated something, but they didn’t explain anything. However, the scientists discovered that having children had significance and decreased the incidence of dementia in the study’s unmarried participants by 60%.
Håberg said, “Some people have theorized that if you have children, you stay more cognitively engaged. For example, you have to deal with people and participate in activities you wouldn’t otherwise have to do. This stimulates your brain so that it possibly works better. That way, you build up a kind of cognitive reserve.”
“We don’t know whether it’s being married or having children that protect against dementia, or if it’s a case of pre-selection, for example. This would mean that people with a lower probability of developing dementia also have a higher probability of finding a partner and having children. But the fact that we have the HUNT Study means that we have a lot of data available that we haven’t yet used to investigate this further.”
The study results are part of the research project REFAWOR (Cognitive reserve work and family) funded by the NIH in the USA, which is part of the program “Changing lives, changing brains” under the auspices of the Norwegian Institute of Public Health.
Scientists are taking a closer look at the significance of having children for dementia risk, the types of work people have, and how retirement age can affect the risk.
Håberg said, “We’ve dreamt of finding a medicine for dementia for a long time, but we haven’t yet succeeded. So we’re looking at social determinants. What can society do to reduce the risk? The state could facilitate having children, for example.”
Vegard Skirbekk at the Norwegian Institute of Public Health (NIPH/FHI) said, “One of the next steps is to look at genetic connections. We know that certain genes increase the risk of dementia, but people with these genes can still live to be 90 years old without experiencing cognitive problems.”
“You could say that the increased risk inherent in the genes can be regarded as a vulnerability, where having a stable family life might reduce this vulnerability.”
“This study says nothing about the biological mechanisms behind dementia. But it shows that being married can influence risk factors. You become more cognitively active, cope better with adversity, and are less subject to stress. The partner represents a security that provides a buffer.”