Relationship between cognitive function and phase angle measured with a bioelectrical impedance system

AimInvestigate the relationship between cognitive function and phase angle, a measure of muscle quality.FindingsPhase angle consistently decreased with worsening general cognition in individuals with Alzheimer's dementia or amnesic mild cognitive impairment in men.MessageOur study strengthened the findings of the very few previous studies indicating that low muscle quality is associated with poor cognitive function. PurposeThe purpose of this study was to investigate the relationship between cognitive function and phase angle (PhA), an indicator of muscle quality.MethodsThis cross-sectional study enrolled outpatients who visited a memory clinic at the Nagoya University hospital from January 2016 to June 2022. We enrolled 153 participants with body composition measurements. Inclusion criteria were a Mini-Mental State Examination score of 20-30 and a clinical diagnosis of Alzheimer's dementia (AD) or amnesic mild cognitive impairment (aMCI). The background characteristics of the participants were compared according to AD and aMCI. Next, linear regression analysis was performed with PhA as the objective variable. In addition, logistic regression analysis was performed for AD diagnosis.ResultsPhA was lower in the AD group (P = 0.009). In linear regression analysis, PhA consistently decreased with worsening ADAS score. In logistic regression analysis, high PhA was associated with absence of AD. Gender-specific analyses showed these associations existed only in men.ConclusionsOur study of patients with AD and aMCI found that PhA decreased with worsening of cognitive function. Compared with aMCI, AD was associated with significantly lower PhA. Our results strengthen the limited evidence in the literature showing that low muscle quality is associated with poor cognitive function.