The researchers started out looking at cardiovascular risk factors — things like high blood pressure, diabetes, excess body weight, and abnormal blood lipid (cholesterol and triglyceride) levels — and how they were linked to the risk of developing dementia in people who took part in a large general health study called the UK Biobank. The researchers also wanted to know how the relationship between these risk factors and dementia varied based on a person’s age and socioeconomic status (income and wealth). A total of 502,226 middle-aged adults, with an average age of 56.5, were included in the analysis. All participants had no prior history of dementia, as indicated by their medical records and any cognitive tests they had taken.
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Different dementia risk patterns in men vs. women
Over a median follow-up period of 11.8 years, 4,068 participants developed dementia, as indicated by cognitive tests they took as part of the study. While 54.4% of participants in the overall study were women, only 45.9% of those who developed dementia were women — and women indeed had a lower incidence of dementia, a rate of 5.88 per 10,000 person-years compared with 8.42 for men. This translated into women having a 17% lower risk of developing dementia.
A number of factors were found to affect the risk for dementia nearly equally in women and men — including currently smoking, diabetes, a high body fat percentage, having had a stroke, and a low socioeconomic status. But the relationship between blood pressure and dementia risk was different in women and men, taking on a “U” shape in men but having a more standard, even slope in women. In other words, having lower or higher blood pressure increased the risk for dementia in men, while lower blood pressure meant a lower dementia risk in women. Overall, the risk for dementia increased by 8% for every systolic blood pressure (the “top number” measured during heartbeats) increase of 20 mmHg, while the same blood pressure increase tended to reduce the risk for dementia by 2% in men — but for men, of course, this number is misleading because it takes into account both increases and decreases in dementia risk at different blood pressure levels.
The different dementia risks for men and women based on blood pressure remained even after the researchers accounted for use of blood pressure medications at the beginning of the study. It also remained consistent when the risk for dementia was broken down into specific types, namely Alzheimer’s disease and vascular dementia.
As noted in a Cosmos article on the study, it’s possible that this study and others like it could lead to changes in recommendations for how blood pressure is treated, at least in people deemed at risk for dementia. It’s possible that women might benefit from a more aggressive approach to blood pressure control, while men might have a lower dementia risk with a more moderate approach. But more research is needed, the study authors wrote, to learn how approaches to treating blood pressure affect the risk for dementia in both women and men.
Want to learn more about protecting your heart? Read “Be Heart Smart: Know Your Numbers,” “Does Diabetes Hurt Your Heart?” “Fight Off Heart Disease With These Five Heart-Healthy Foods” and “Lower Your Risk of Heart Disease.”
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