Taller men may have lower dementia risk in old age: Study

Men who are taller may have a lower risk of dementia later in life, according to a Danish study.

Finding ways to identify individuals at risk of dementia can help people take preventive measures, or plan for their future care, the researchers from the University of Copenhagen in Denmark noted.

The study, published in the journal eLife, indicates that young adult height might be one potential risk factor to consider.

Dementia is a collective term used to describe various symptoms of cognitive decline, such as forgetfulness.

Previous studies have suggested that height may be a risk factor for dementia, the researchers said.

However, much of this research was not able to take into account genetic, environmental, or other early-life factors that may be linked to both height and dementia, they said.

"We wanted to see if body height in young men is associated with diagnosis of dementia, while exploring whether intelligence test scores, educational level, and underlying environmental and genetic factors shared by brothers explain the relationship," said Terese Sara Hoj Jorgensen, Assistant Professor at the University of Copenhagen.

The researchers analysed data on 666,333 Danish men born between 1939 and 1959, including 70,608 brothers and 7,388 twins.

They found a total of 10,599 men who developed dementia later in life.

Their adjusted analysis of this group showed that there was about a 10 per cent reduction in the risk of developing dementia for about every 6 centimetres of height in individuals above the average height.

The researchers found that the relationship between height and dementia also existed when they looked at brothers with different heights.

They suggest that genetics and family characteristics alone do not explain why shorter men had a greater dementia risk.

This was also true when they studied data concerning twins, although the results for this group were less certain, according to the researchers.

"A key strength of our study is that it adjusted for the potential role of education and intelligence in young men's dementia risk, both of which may build up cognitive reserve and make this group less vulnerable to developing dementia," said Merete Osler, Professor at the University of Copenhagen.

Cognitive reserve refers to the brain's ability to improvise, and solve problems that come up in everyday life.

"Together, our results point to an association between taller body height in young men and a lower risk of dementia diagnosis later in life, which persists even when adjusted for educational level, and intelligence test scores," Osler said.

"Our analysis of the data concerning brothers confirms these findings, and suggests the association may have common roots in early-life environmental exposures that are not related to family factors shared by brothers, she said.

Osler added that an important limitation of the study is the uncertainty as to whether these findings are generalisable to women.