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Insulin resistance increases Alzheimer’s risk in middle-aged adults
Late middle-aged adults with insulin resistance may be at greater risk for developing Alzheimer’s disease, according to research in JAMA Neurology.
In a population-based, cross-sectional study of middle-aged adults with and without a parental history of Alzheimer’s disease, researchers conducting imaging analysis found that adults with higher insulin resistance also had lower glucose metabolism in the brain’s lower left medial temporal lobe, which researchers found was related to memory function.
Barbara B. Bendlin
Barbara B. Bendlin, PhD, of the University of Wisconsin School of Medicine and Public Health, and colleagues analyzed data from 150 adults aged 48 to 71 years (mean age, 61 years; 108 women; 103 with a parental history of Alzheimer’s disease) with normal cognition included in the Wisconsin Registry for Alzheimer’s Prevention study, a community sample with a large percentage of participants with a parental history of Alzheimer’s disease. Within the cohort, 61 participants were carriers of the apolipoprotein E epsilon 4 allele, a genetic risk factor for Alzheimer’s disease. Cognitive testing and MRI and fluorodeoxyglucose (FDG)-PET scans were performed at baseline. Researchers measured glucose and insulin levels after a 12-hour fast and used homeostasis model assessment of insulin resistance (HOMA-IR).
In the study, higher HOMA-IR was associated with lower glucose metabolism (P < .01) as well as lower regional glucose metabolism across large portions of the frontal, lateral parietal, lateral temporal and medial temporal lobes. Researchers also found that lower glucose metabolism in the left medial temporal lobe, where the association was especially strong, correlated with worse immediate memory function (P < .001) and delayed memory (P < .001).
“This study provides evidence that insulin resistance is associated with brain glucose metabolism in a late middle-aged cohort enriched for [Alzheimer’s disease] risk factors,” the researchers wrote. “The prevalence of [Alzheimer’s disease] continues to grow, and midlife may be a critical period for initiating treatments aimed at preventing or delaying the onset of [Alzheimer’s disease].”– by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.