Phase Angle Measure of Muscle Quality Correlates with Dementia Risk
Researchers have established a relationship in old individuals between the age-related loss of muscle mass and strength leading to sarcopenia and risk of dementia, but have not yet established good measures to quantify the early development of these pathologies in middle aged individuals. Phase angle is a measure of muscle quality derived from electrical impedance of muscle tissue, and here researchers provide evidence for phase angle to be a useful tool in assessing the early stages of muscle decline and cognitive decline. Early detection of the consequences of degenerative aging can allow better management of the decline at this point in time, and later will be an indication of the need for earlier use of rejuvenation therapies.
Sarcopenia is a condition characterized by the progressive loss of skeletal muscle mass and function. Gowing evidence has highlighted the novel significance of the phase angle (PhA) in the diagnosis of sarcopenia. PhA is an indicator of cellular health that reflects intracellular and extracellular fluid status, cellular nutritional status, cell membrane integrity and cell function. PhA and handgrip strength (HGS) were reported to be associated with malnutrition, a risk factor for sarcopenia, but PhA proved to be a more sensitive indicator than HGS. Other studies have shown that PhA is lower in individuals with sarcopenia than in those without sarcopenia. In a previous study, we revealed that PhA is an index of muscle quality and is useful for detecting sarcopenia. These findings suggest that muscle quality, as well as muscle mass, strength and physical performance, would be valuable indices for the diagnosis of sarcopenia.
This was a cross-sectional study involving 263 participants (163 men with a median age of 60 years and 100 women with a median age of 58 years) who underwent a general health examination. Sarcopenia-related indices included appendicular skeletal muscle mass (ASM)/height^2, ASM/body mass index, handgrip strength (HGS), HGS/upper extremity skeletal muscle mass and phase angle (PhA). We examined the associations between these indices and cognitive function using the Japanese version of the Montreal Cognitive Assessment (MoCA-J).
Higher PhA, an indicator of muscle quality, was associated with a lower risk of mild cognitive impairment (MCI) in women (adjusted odds ratio = 0.28), whereas the other sarcopenia-related indices showed no significant association with MCI in both sexes. The PhA of women was positively associated with the MoCA-J scores (β = 0.27). Moreover, the PhA of women showed a positive correlation with cognitive subdomains, including memory (r = 0.22), which is one of the earliest manifestations of cognitive impairment. The PhA in men was also positively correlated with memory.
Within a year every fitness and longevity channel on Youtube will be talking about phase angle testing as if it something they have tested for all their lives.