Image by BGStock72/Shutterstock

A body composition analyzer is an easy-to-use device that can measure parameters such as body weight, body fat, and muscle mass when the subject steps on it. Researchers at the University of Tsukuba evaluated the indicators of muscle quality (muscle cell condition and extracellular to intracellular water ratio) from the measured parameters. Through a follow-up study of up to 12 years, the researchers clarified that high-risk older adults requiring long-term care can be predicted using the data from the body composition analyzer.

Tsukuba, Japan—As the global population ages, preventing functional decline and the need for long-term care among older adults becomes urgent. One simple way of evaluating a person's physical condition is to use a body composition analyzer for muscle mass assessment. However, recent studies have raised questions about the relationship between muscle mass and health, and the need to focus on "muscle quality" has been pointed out.

A body composition analyzer measures the body's electrical resistance by applying a weak alternating current to the latter. By applying multiple frequencies of current, the cell membrane's state (phase angle) and the ratio of intracellular water to extracellular water can be evaluated. As reported in many studies, this method makes it possible to identify tissues that do and do not contribute to muscle contraction; in other words, the "muscle quality." Because muscle contraction is essential for daily activities, this index may be associated with the risk of future dependence on nursing care.

In this study, researchers calculated two indicators (the phase angle and extracellular to intracellular water resistance ratios) from the body composition data of 858 older adults aged ≥65 years in Kasama City, Ibaraki Prefecture. Thereafter, they followed up with these older adults for up to 12 years to examine the relationship between these indicators and the need for long-term care. The results showed that people with low phase angles and extracellular to intracellular water resistance ratios (indicators of lower limb muscle quality) are at high risk of becoming dependent. This tendency is exceptionally high when the values are lower than the median for each indicator. In addition, based on the survey results, researchers calculated the standard values for each indicator to determine whether or not a person is likely to become dependent within 4 and 10 years, respectively. It is important to note that the conventional indicators of muscle mass were not significantly associated with future dependence per our findings.

The body composition analyzer can easily measure a wide range of parameters when the subject steps on it, and no person is needed to operate the device. By installing the device in medical facilities and community centers and encouraging its widespread use, it may be possible to efficiently and comprehensively identify older adults at high risk of requiring long-term care.

###
This work was supported by the JSPS KAKENHI [grant number 23KJ0273] and JST [grant number JPMJPF2017].

Original Paper

Title of original paper:

Segmental phase angle and the extracellular to intracellular water ratio are associated with functional disability in community-dwelling older adults: A follow-up study of up to 12 years

Journal:

Nutrition

DOI:

10.1016/j.nut.2025.112709

Correspondence

Professor OKURA Tomohiro
Institute of Health and Sport Sciences, University of Tsukuba

Related Link

Institute of Health and Sport Sciences