A longitudinal analysis published Wednesday in Neurology found that risk factors associated with developing dementia varied by age, suggesting that doctors likely need to consider "age, sex, vascular risk burden, and end-organ damage" when assessing a patient's risk of developing the condition.
Study details and key findings
For the study, researchers evaluated participants in the Framingham Heart Study who had available Framingham Stroke Risk Profile (FSRP) data. To better assess the relationship between all-cause dementia and vascular risk factors in the Framingham Heart Study, they added a genetic risk score for Alzheimer's dementia to their model.
According to Emer McGrath of National University of Ireland Galway and his co-authors, FSRP was developed and validated for its ability to predict 10-year stroke risk in patients 55 and older. "The FSRP has also been associated with brain atrophy and cognitive decline in a community-based setting," the study authors wrote. "However, it is unknown if the FSRP is predictive of dementia risk across mid- to later-life or if the association between component vascular risk factors and incident dementia varies with age."
In their analysis, the researchers measured risk factors at five timepoints, including a midlife measurement at age 55, then again at ages 65, 70, 75, and 80.
At age 55, the study included 4,899 participants, 57.2% of which were women. By age 80, there were just 2,386 dementia-free participants with available data, 62.1% of which were women.
At age 65, researchers started conducting 10-year dementia follow-up periods. They tracked participants from the first risk factor measurement to the time of incident dementia, death, or until the last time they were confirmed not to have dementia.
According to the study, diabetes and high systolic blood pressure were the most important predictors of future dementia at age 55. At age 65, non-stroke cardiovascular disease was the most important factor for predicting 10-year risk of dementia. For participants in their 70s, diabetes and stroke were the most important predictors.
However, at age 80, diabetes, stroke history, and antihypertensive use were the strongest predictors of 10-year risk of dementia.
"Predicting a person's future risk of dementia likely needs to be made at an individual level, taking age, sex, vascular risk burden, and end-organ damage into account," McGrath said.
"It is likely that controlling high blood pressure, preventing diabetes mellitus, and following a healthy lifestyle could help reduce a person's risk of dementia later on," she added.
However, according to the authors, the study faced several limitations. In particular, they noted that the Framingham sample was predominantly Caucasian, meaning its results may not apply to other populations.
And while the analysis included dementia-free survivors at five-year intervals, the researchers noted that participants with more severe vascular risk profiles may have died between exam periods, swaying the results.
In addition, the researchers used clinical criteria rather than biomarker-based criteria when diagnosing the condition, and they did not evaluate dementia subtypes.
Ultimately, McGrath and co-authors concluded that the study's "findings support the use of age-specific dementia risk scores which should prioritize including at age 55, systolic blood pressure and diabetes mellitus; age 65, non-stroke cardiovascular disease; ages 70 and 75, diabetes mellitus and stroke; and age 80, diabetes mellitus, stroke and antihypertensive use." (George, MedPage Today, 5/18; McGrath et al., Neurology, 5/18)