LIBRA Index Synopsizes Brain Health, Higher Scores Indicate Dementia Risk
Investigators used cross-sectional data from the observational population-based cohort of the Maastricht Study, calculating LIBRA scores with 12 dementia risk and protective factors.
Irene S. Heger, MSc
The LIfestyle for BRAin health (LIBRA) index may meaningfully summarize individual lifestyle-related brain health, as higher health and lifestyle-based dementia risk were associated with markers of general brain atrophy, a recent study found.
Investigators included a total of 4164 patients with a mean age of 59 and higher LIBRA scores (mean, 1.19; range, –2.7 to 9.2) from the Maastricht Study—an observational population-based study evaluating different components of type 2 diabetes mellitus (T2DM), characterized by an extensive phenotyping approach. Participants in the current sample with higher LIBRA scores were also found to have higher volumes of white matter hyperintensities (WMH) (ß = 0.051; P = .002), lower scores on information processing speed (ß = –0.067; P = .001), and executive function and attention (ß = –0.065; P = .004). Associations between LIBRA and volumes of grey matter (ß = –0.093; P <.001), cerebrospinal fluid (ß = 0.104; P <.001), and memory (ß = –0.054; P = .026) were found only in men, who comprised 49.7% of the study population.
“The results confirm previous studies showing that higher LIBRA scores are related to lower cognitive functioning and higher risk for cognitive impairment and dementia in the general population and clinical studies,” Irene S. Heger, MSc, researcher, department of psychiatry and neuropsychology, School for Mental Health and Neuroscience, Maastricht University, the Netherlands, et al wrote. “Importantly, our study shows a relationship of LIBRA with underlying biological gradients of WMH and global atrophy using population MRI imaging, showing it is indeed an index of brain health.”
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When calculating weighted compound LIBRA scores, 12 dementia risk and protective factors were included, such as hypertension and physical activities, with higher scores indicating greater dementia risk. Brain MRI was performed on a 3 TESLA scanner, evaluating standardized volumes of white matter, grey matter, cerebrospinal fluid, white matter hyperintensities, as well as the presence of cerebral small vessel disease. Cognitive functioning was evaluated in terms of memory, information processing speed, and executive functioning and attention, with cognitive impairment defined as values of 1.5 or less below average.
“We showed that a compound score of health and lifestyle factors is associated with brain markers and cognition, even after adjustment for the contribution of the nonmodifiable factors age, sex, and education,” Heger et al wrote. “The use of a compound score that includes risk and protective factors all within the reach of vascular risk management and lifestyle interventions makes the LIBRA index a useful tool in identifying a group of individuals at increased risk of cognitive decline and dementia and for monitoring treatment targets over time in dementia prevention trials.”
Of the original 7689 participants in the Maastricht study, 45.8% (n = 3525) were excluded from the LIBRA study, most often due to missing MRI data. Physical inactivity, adherence to a Mediterranean diet, and low to moderate alcohol intake were the most often missing LIBRA factors. Excluded participants had a more unfavorable LIBRA risk profile, as well as a higher presence of T2DM, hypertension, heart disease, obesity, chronic kidney disease, depression, physical inactivity, and were more often smokers.
The study was limited due to its cross-sectional design, as well as the potential for selection bias as a result of missing MRI data. The predictive value of the LIBRA index may have been weakened by the absence of the LIBRA factor cognitive activity—the strongest protective factor. Small changes in a specific factor in behavioral change programs may have also been undetected due to the use of dichotomous LIBRA scores.
Investigators noted that further research should consider sex differences in lifestyle-related pathology and cognition, adding that improving LIBRA factors for individuals could impact overall population brain health.
