MONTREAL — Social and economic disadvantage may explain, at least in part, women’s higher risk of developing dementia, a new study suggests.
A survey of some 30,000 people in 18 countries found that the risk of dementia was higher among women in poor countries, even though the risk factors affected both men and women.
“There has been this notion for a long time that women are more at risk of dementia than men,” commented Professor Sylvie Belleville, who holds the Canada Research Chair in Cognitive Neuroscience of Aging and Brain Plasticity.
“It’s really a bit intriguing and we now know that there are a whole bunch of lifestyle factors, or things that happen to us during life, that are going to impact our risk of developing dementia. .”
This study, she continues, “greatly refines our understanding and illustrates the complexity of dementia, how different factors interact to increase our risk”, whether it is socio-economic background, social background or even generation.
Women’s higher risk of dementia is often associated with their greater longevity than men, which increases the number of years the disease can manifest.
A study published in 2020, however, calculated that up to 40% of the risk of dementia might be attributable to twelve modifiable risk factors: less education, hypertension, obesity, diabetes, depression, problems with hearing, smoking, excessive alcohol consumption, physical inactivity, poor social network, brain injury and exposure to air pollution.
Several of these factors are very present in underprivileged countries and can particularly affect women. For example, women may have limited access to education (and therefore to jobs that stimulate them intellectually) or to quality health care, which may have a negative impact on their cognitive health later in life.
“When we look at the data (from the study), we can clearly see that there is really an increased risk in women depending on the type of country where you live, if you live in a country that is socioeconomically more disadvantaged, whereas this disadvantage effect is not found in men,” said Ms. Belleville.
The impact of the country in which one lives on the risk of suffering from dementia is particularly important for women, but not for men, she specifies. “It’s still incredible as given,” said the researcher.
Can we conclude that the fact, for a woman, of living in a disadvantaged neighborhood in a rich country will increase her risk of dementia, as is the case for a woman who lives in a poor country? “Probably, but we don’t know too much in fact,” admitted Ms. Belleville, who recalls that we still have to dissect the study data to better understand what explains the observed effect.
This study also demonstrates that it is possible to reduce women’s risk of dementia not only on a personal level, but also on a societal level, Belleville said. We thus observe a more modest risk among younger women, which might testify to the impact of the measures put in place to reduce inequalities.
Some projections indicate that up to 150 million people might suffer from dementia worldwide in 2050, three times more than in 2019. Rates of dementia are rising particularly rapidly in lower- and middle-income countries.
The findings of this study were published by the medical journal Alzheimer’s & Dementia.
