Measures of Adiposity and Alzheimer’s Disease-Related MRI Markers: The Northern Manhattan Study

Article type: Research Article

Authors: Caunca, Michelle R.^{a; b; c} | Simonetto, Marialaura^c | Alperin, Noam^{b; d} | Elkind, Mitchell S.V.^e | Sacco, Ralph L.^{a; b; c} | Wright, Clinton B.^f | Rundek, Tatjana^{a; b; c; *}

Affiliations: [a] Division of Epidemiology and Population Health Sciences, Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, USA | [b] Evelyn F. McKnight Brain Institute, University of Miami, Miami, FL, USA | [c] Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA | [d] Department of Radiology, Miller School of Medicine, University of Miami, Miami, FL, USA | [e] Department of Epidemiology, Mailman School of Public Health, and Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA | [f] National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA

Correspondence: [*] Correspondence to: Tatjana Rundek, MD, PhD, 1120 NW 14th St., 13th Floor, Miami, FL, 33136, USA. Tel.: +1 305 243 7847; Fax: +1 305 243 7081; E-mail: t.rundek@med.miami.edu.

Abstract: Background:Adiposity may increase risk for dementia and Alzheimer’s disease (AD), but mechanisms are unclear. Objective:To examine associations between measures of adiposity with AD-signature region cortical thickness and hippocampal volume. Methods:We used data from the Northern Manhattan Study, a clinically stroke-free cohort of mostly Hispanic participants. Exposures of interest included body mass index (BMI), waist-hip-ratio (WHR), waist circumference (WC), and adiponectin concentration, measured at study entry. AD-signature region cortical thickness and hippocampal volume were obtained using Freesurfer. We estimated associations using multivariable linear regression, adjusting for sociodemographics and health behaviors. We re-examined estimates after adjustment for APOE ɛ4 allele status or carotid intima-media thickness (cIMT), among those cognitively unimpaired, and after weighting for the inverse probability of selection into the MRI sub-study. We also repeated analyses for cortical thickness in non-AD signature regions. Results:The sample (N = 947, 63% women, 66% Hispanic/Latino, 26% obese) had a mean (SD) age = 63 (8) years. Greater BMI and WC (both z-scored) were associated with thinner AD-signature region cortex (also z-scored) (BMI: β [95% CI] = –0.09 [–0.18, –0.01], WC: β [95% CI] = –0.11 [–0.20, –0.02]). We did not find evidence that adiposity was related to hippocampal volume. Results were consistent after adjustment for APOE ɛ4 allele status or cIMT, after weighting for selection, among those cognitively unimpaired, and for non-AD signature region cortical thickness. Conclusion:Greater BMI and WC were related to cortical thinning within and outside the AD-signature region, suggesting a global effect not specific to AD.

Keywords: Adiposity, brain aging, epidemiology, neuroimaging, structural MRI

DOI: 10.3233/JAD-190092

Journal: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 995-1004, 2019