APOE4 Genotype Relates with Body Mass and Percent Fat Mass in Cognitively Normal Older Adults

Abstract

AbstractBackgroundLower body mass is related to the progression of Alzheimer’s disease (AD). Carriers of the APOE e4 (APOE4) allele have an increased risk of developing AD, and APOE4 status has been shown to be associated with decreased body mass and fat mass in AD. However, this relationship in cognitively normal older adults is unclear. We investigated whether body mass index (BMI) and body composition are related with APOE4 status in cognitively normal older adults.MethodBaseline data from 211 cognitively normal older adults in an ongoing nutrition intervention RCT (Nutrition Intervention for Cognitive Enhancement; NICE study) were analyzed. Whole blood was attained, and genetic analyses were used to determine APOE genotype. Participants with ≥ 1 APOE4 allele were classified as APOE4 carriers. BMI was calculated from weight and height. Fat mass percentage was measured using dual energy x‐ray absorptiometry. We compared means between APOE4 carriers and non‐carriers for BMI and fat mass percentage using covariate‐adjusted ordinary least squares (OLS) regression models (i.e., ANCOVA), adjusting for age and sex. Statistical analyses were performed using R (v. 4.2.2; R Foundation, Vienna, Austria). Statistical significance was set at p < 0.05.ResultParticipants were 75% female with a mean age of 71.4 ± 4.9 years. 34% of participants were APOE4 carriers. Mean BMI and percent fat mass were 28.4 ± 4.6 kg/m2 and 40% ± 4.6, respectively. ApoE4 carriers had significantly lower BMI (27.5 kg/m2 ± 3.9 vs. 28.9 kg/m2 ± 4.8, p = 0.02) and lower body fat percentage (38% ± 8.0 vs. 42% ± 6.7, p < 0.01) compared to non‐carriers, respectively.ConclusionIn this study, cognitively normal older adult APOE4 carriers had lower BMI and lower body fat percentage compared to non‐carriers. These findings suggest that APOE4 status may influence body weight and body composition, which may represent a way APOE4 increases the risk of symptomatic AD. Future studies are needed to explore the mechanisms underpinning the relationship of APOE4 with decreased body mass and differential body compositions and to determine if these results are consistent in different life stages.