| Autor: |
Edmunds, Kyle J, Breidenbach, Bri M, McIntyre, Clayton Connor, Lose, Sarah R, Bendlin, Barbara B, Sager, Mark A., Asthana, Sanjay, Johnson, Sterling C, Okonkwo, Ozioma |
| Zdroj: |
Alzheimer's & Dementia: The Journal of the Alzheimer's Association; Dec2023 Supplement 14, Vol. 19, p1-1, 1p |
| Abstrakt: |
Background: Age is the cardinal risk factor for Alzheimer's disease (AD), as well as adverse cardiovascular health and insulin resistance. In the context of promoting cerebrovascular health and resilience to AD, it remains unclear whether cardiorespiratory fitness (CRF)—an important lifestyle factor reflective of habitual exercise—explains age‐related associations in insulin signaling. Understanding how these factors intersect may be crucial for designing effective lifestyle interventions to protect normative brain function in aging. This study examines whether CRF mediates the relationship between age and insulin resistance in a sample enriched with risk for AD. Method: We included n = 1,131 cognitively unimpaired, nondiabetic participants. CRF was estimated using a validated equation that incorporates age, sex, BMI, resting heart rate, and self‐reported physical activity. The Homeostatic Model Assessment for Insulin Resistance (HOMA‐IR) quantified insulin resistance using measured plasma glucose levels in mg/dL and insulin in µIU/mL following a 12‐hour fast. Cross‐sectional linear regression models were assembled in a mediation framework to test the mechanistic influence of CRF using the IBM SPSS PROCESS Macro v3.4, where indirect effects were estimated using bootstrapping. All models controlled for age, education, Apolipoprotein E4 (APOE4) carriage, body mass index (BMI), and familial history of AD. Result: 71.8% of participants had family history of AD and 38.8% were APOE4 carriers. Participants had a mean age of 64.5 ± 7 years and a mean of 16 ± 3 years of education. Age was significantly associated with estimated CRF [β = ‐0.346; p<0.001] and HOMA‐IR [β = ‐0.036; p<0.01]; CRF was likewise negatively correlated with HOMA‐IR [β = ‐0.106; p<0.001]. Bootstrapping indicated that CRF was a significant partial mediator of the association between age and HOMA‐IR [β = 0.37; 95% CI: 0.19, 0.55]. Conclusion: Age exerts its deleterious influence on peripheral insulin resistance through the degradation of cardiorespiratory fitness among adults at risk for AD. [ABSTRACT FROM AUTHOR] |
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