Recent studies have pointed to a link between phosphate and muscle function, and researchers from Taiwan's National Defense Medical Center, Taoyuan Armed Forces General Hospital, and National Taiwan University sought to investigate how phosphate levels influenced muscle strength, as well as dynapenia and sarcopenia risk.
Greater age, higher risk
Taking their data from the National Health and Nutrition Examination Survey (NHANES), they assessed a total of 7,421 subjects aged 20 and above, recording their anthropometric parameters, quadriceps muscle strength, and appendicular lean masses.
They then adjusted for pertinent variables, and reported an inverse relationship between serum phosphate quartiles and muscle strength.
In addition, "the linear association was stronger than other anthropometric parameters", and a significant link between phosphate levels and muscle strength was seen in those above the age of 65, but not in those aged 20 to 65.
They further wrote that across the entire study population, those in the higher phosphate quartiles were more likely to develop dynapenia than sarcopenia, and exhibit lower muscle strength.
Lacking in some areas
However, they added that the study's results could not apply to causal inferences as it was a cross-sectional observational analysis of an existing database.
They also did not explore the long-term relationship between muscle strength loss and fluctuations in serum phosphate levels, due to there being no record of repeated observations of the aforementioned clinical variables.
Moreover, data on "potentially confounding" inflammatory biomarkers, such as IL-6 (interleukin 6) and TNFα (tumour necrosis factor alpha), were inaccessible on the NHANES database. This meant the researchers were unable to study their possible influence on muscle strength.
Platform for further study
They wrote that the present study did indeed highlight the inverse association between higher phosphate levels and lower muscle strength, as well as a higher risk for "predicting the presence of dynapenia".
They added that hyperphosphatemia could lead to impaired muscle function that harboured "a predisposing milieu for the decline of muscle strength and development of dynapenia".
In conclusion, they wrote: "Although no prospective randomised controlled trial was assessable, our study provides epidemiologic evidence and a plausible pathophysiological mechanism for future studies to use to determine a strategy for the prevention of dynapenia and physical disabilities."
Source: Scientific Reports
"Exploring the Link between Serum Phosphate Levels and Low Muscle Strength, Dynapenia, and Sarcopenia"
Authors: Yuan-Yuei Chen, et al.
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