Five-Year Change in Body Mass Index Predicts Conversion to Mild Cognitive Impairment or Dementia Only in APOE ɛ4 Allele Carriers

Article type: Research Article

Authors: Kadey, Kylie R.^a | Woodard, John L.^a | Moll, Allison C.^a | Nielson, Kristy A.^{b; c} | Smith, J. Carson^d | Durgerian, Sally^e | Rao, Stephen M.^{f; *}

Affiliations: [a] Department of Psychology, Wayne State University, Detroit, MI, USA | [b] Department of Psychology, Marquette University, Milwaukee, WI, USA | [c] Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA | [d] Department of Kinesiology, University of Maryland, College Park, MD, USA | [e] BrainDataDriven LLC, Shorewood, WI, USA | [f] Schey Center for Cognitive Neuroimaging, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA

Correspondence: [*] Correspondence to: Stephen M. Rao, Schey Center for Cognitive Neuroimaging, Neurological Institute, Cleveland Clinic, 9500 Euclid Ave/U10, Cleveland, OH 44195, USA. Tel.: +1 216 312 4168; E-mail: [email protected].

Abstract: Background:Body mass index (BMI) has been identified as an important modifiable lifestyle risk factor for dementia, but less is known about how BMI might interact with Apolipoprotein E ɛ4 (APOE ɛ4) carrier status to predict conversion to mild cognitive impairment (MCI) and dementia. Objective:The aim of this study was to investigate the interaction between APOE ɛ4 status and baseline (bBMI) and five-year BMI change (ΔBMI) on conversion to MCI or dementia in initially cognitively healthy older adults. Methods:The associations between bBMI, ΔBMI, APOE ɛ4 status, and conversion to MCI or dementia were investigated among 1,289 cognitively healthy elders from the National Alzheimer’s Coordinating Center (NACC) database. Results:After five years, significantly more carriers (30.6%) converted to MCI or dementia than noncarriers (17.6%), p < 0.001, OR = 2.06. Neither bBMI (OR = 0.99, 95%CI = 0.96–1.02) nor the bBMI by APOE interaction (OR = 1.02, 95%CI = 0.96–1.08) predicted conversion. Although ΔBMI also did not significantly predict conversion (OR = 0.90, 95%CI = 0.78–1.04), the interaction between ΔBMI and carrier status was significant (OR = 0.72, 95%CI = 0.53–0.98). For carriers only, each one-unit decline in BMI over five years was associated with a 27%increase in the odds of conversion (OR = 0.73, 95%CI = 0.57–0.94). Conclusion:A decline in BMI over five years, but not bBMI, was strongly associated with conversion to MCI or dementia only for APOE ɛ4 carriers. Interventions and behaviors aimed at maintaining body mass may be important for long term cognitive health in older adults at genetic risk for AD.

Keywords: Alzheimer’s disease, Apolipoprotein E4, body mass index, cognitive dysfunction, dementia

DOI: 10.3233/JAD-201360

Journal: Journal of Alzheimer's Disease, vol. 81, no. 1, pp. 189-199, 2021