High blood pressure, genetics are risk factors for cognitive impairment

Combination of factors led to more accurate prediction of who developed cognition issues in 5 years

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Older age at the onset of disease, high blood pressure, poor cognitive and motor function, and mutations in the APOE gene are risk factors of future cognitive impairment in newly diagnosed Parkinson’s disease, a study showed.

The combination of these factors was able to more accurately predict which patients developed cognitive impairment over five years of follow-up than older age alone.

“Our study may contribute to the early identification of [cognitive impairment] in [Parkinson’s disease] patients,” the researchers wrote in “Predictors of cognitive impairment in newly diagnosed Parkinson’s disease with normal cognition at baseline: A 5-year cohort study,” which was published in Frontiers in Aging Neuroscience.

Cognitive problems — from mild cognitive impairment to dementia — are a common nonmotor Parkinson’s symptom. Cognitive impairment “can potentially occur at different stages, severely affect the quality of life and function, and increase caregiver burden and health-related costs,” the researchers wrote.

Identifying the risk factors of future cognitive impairment may help identify patients at higher risk and implement strategies to prevent such problems or their progression.

A research team led by scientists in China sought to identify risk factors of future cognitive impairment (either mild cognitive impairment or dementia) in newly diagnosed patients with normal cognitive function. They looked at data from 409 people diagnosed with Parkinson’s within two years of entering the Parkinson’s Progression Markers Initiative (PPMI) and who were followed for at least five years. The PPMI is a large international study following patients and healthy people over time.

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Among the 358 patients with available cognitive data at the study’s start (baseline) and follow-up, 232 (64.8%) showed no signs of cognitive problems at baseline and were included in the final analysis.

A total of 94 of the 232 (40.5%) eventually developed cognitive impairment, as indicated by a score of 25 or lower on a standardized cognition test called the Montreal Cognitive Assessment (MoCA).

Statistical models accounting for multiple factors showed several demographic, clinical, and genetic features were significantly associated with developing cognitive impairment.

These included older age at disease onset, current diagnosis of hypertension (high blood pressure), lower baseline MoCA scores, and worse baseline motor symptoms, as assessed with part 3 of the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS).

Carrying a mutation in both copies of the APOE gene that’s linked to Parkinson’s  and faster rate of cognitive decline also meant a significantly increased risk of cognitive impairment.

“Apart from older age, the strongest clinical predictors [of cognitive impairment] were current diagnosis of hypertension, lower baseline MoCA scores, APOE status, and to a lesser extent, [worse motor symptoms],” the researchers wrote.

Combining these factors let researchers more accurately identify those who ended up developing cognitive decline than using older age alone.

Among the study’s limitations, the researchers noted they couldn’t differentiate between mild cognitive impairment and more severe dementia due to the relatively small sample size. They also didn’t account for the effect of treatments.

“A larger sample and much more comprehensive assessment, and prolonged follow-up will be required in a future study,” they wrote.