Good midlife heart health linked to lower dementia risk later on
Author: Caroline White
Good cardiovascular health at the age of 50 is associated with a lower risk of dementia later in life, finds a study* of British adults published in The BMJ.
The findings lend weight to public health policies designed to improve cardiovascular health in middle age to promote brain health in later life.
Dementia can start to develop 15-20 years before any symptoms appear, so identifying factors that might prevent its onset is important.
The American Heart Association’s “Life Simple 7” cardiovascular health score, initially designed for cardiovascular disease, has been suggested as a potential option for this.
Designed to prevent the development of risk factors themselves, it is the sum of four behavioural (smoking, diet, physical activity, body mass index) and three biological (fasting glucose, blood cholesterol, blood pressure) metrics, categorised into cardiovascular health scores: poor (0-6); intermediate (7-11); and optimal (12-14).
But the evidence has been inconsistent. So, an international research team looked at the association between the “Life Simple 7” cardiovascular health score at age 50 and dementia risk over the next 25 years.
Their findings are based on cardiovascular health data collected from 7,899 50-year-old healthy British men and women in the Whitehall II Study, which is looking at the impact of social, behavioural, and biological factors on long-term health.
Dementia cases were identified using hospital, mental health services, and death register information up to 2017.
Some 347 cases of dementia were recorded over an average monitoring period of 25 years. Average age at diagnosis was 75.
After taking account of potentially influential factors, the researchers found that adherence to the “Life Simple 7” cardiovascular health recommendations in midlife was associated with a lower risk of dementia later in life.
Compared with an incidence rate of dementia of 3.2 per 1000 person years among those with a poor cardiovascular score, those with an intermediate score had an incidence of 1.8, while those with an optimal score had an incidence of 1.3.
A higher cardiovascular health score at age 50 was also associated with higher whole brain and grey matter volumes in MRI scans 20 years later. And reductions in dementia risk were also evident across the continuum of the cardiovascular score, suggesting that even small improvements in cardiovascular risk factors at age 50 may reduce dementia risk in old age, say the researchers.
“Our findings suggest that the Life’s Simple 7, which comprises the cardiovascular health score at age 50 may shape the risk of dementia in a synergistic manner,” they write. “Cardiovascular risk factors are modifiable, making them strategically important prevention targets. This study supports public health policies to improve cardiovascular health as early as age 50 to promote cognitive health,” they conclude.
In a linked editorial**, researchers from the University of Cambridge and the Newcastle University agree but point out: “However, other evidence makes clear that vascular health at 50 is determined by factors earlier in the life course, including inequality and social and economic determinants.
”They add: “We know that risk can change across generations, and in the UK the prevalence of dementia has decreased by nearly 25% when standardised for age.”
And they conclude: “Although the Whitehall study cannot reflect the UK’s population, estimates obtained from this cohort reinforce the need for action to shift population risk profiles for cognitive decline and dementia across the life course.”
*Sabia S, Fayosse A, Dumurgier J, et al. Association of ideal cardiovascular health at age 50 with incidence of dementia: 25 year follow-up of Whitehall II cohort study. BMJ 2019; 3664.
**Brayne C, Matthews FE. The determinants of cognitive decline and dementia. BMJ 2019; 366 :l4946