Using relative handgrip strength to identify children at risk of sarcopenic obesity
Michal Steffl, Jan Chrudimsky, James J. Tufano
A review by James Shmagranoff
Introduction
The ability to monitor, diagnose, and treat diseases in the early stages is always on the forefront of people’s minds, but, unfortunately, due to cost prohibitive screenings and specialized equipment, it is not always an option to people. In order to combat not only the cost of detailed screenings, but also to eliminate the need for advanced technology, fitness testing of physical characteristics have begun to be implemented. Hand grip strength testing is a great method to test for general muscle strength and numerous medical conditions such as a child’s increased metabolic risk, diabetes, malnutrition, or adult and elderly muscular atrophy and dystrophy, sarcopenia, and other cardiometabolic factors.
Sarcopenia is characterized by muscle mass and strength decrease, and while it is usually related to the elderly, recent studies have shown that children are also showing signs of sarcopenia. Now, obesity in children is also a world-wide issue, and because of this, it is leading researchers to ask the question on if obesity is causing a lack of muscle mass or if a lack of muscle mass is causing obesity. So far it appears that obesity seems to cause sarcopenia, known as “sarcopenic obesity”, which occurs when lean mass is less than fat mass. Sarcopenic obesity does not necessarily mean that a child is obese in the relative term, but that they have a low muscle mass level covered up by fat mass. The issue is that these children would appear to look like normal, healthy children, so a mechanism for determining if children do have sarcopenic obesity and can benefit from early intervention would be very beneficial.
Because of the various rates that children develop, physical fitness measures are difficult to relate across the board to all children, so to combat this various methods involving measuring skeletal muscle mass(SMM) to body fat mass(BFM), muscle-fat ratio(MFR), body mass index(BMI), body composition, and muscle strength were proposed for measuring sarcopenia. It was found that using hand grip strength became a quick and cheap way to determine sarcopenia in the elderly when compared to BMI, but there was only limited information on using this method for children, so this study aims to find the relationships between MFR and grip-to-BMI in hopes that grip-to-BMI can be used to find at risk children as well as show differences between those who are not at risk of sarcopenic obesity.
Methods
Participants: 730 girls(353) and boys(377) ages 4-14 in the Czech Republic who participated in an active lifestyle promotional event were used in this study non-exclusively or -inclusively just to maintain a good range of child body types. The children were almost equally distributed in those who did not participate in any sports, those who did gymnastics, those in soccer/hockey, and those in individual sports such as karate. It was split 1:1:2 for those who did no sporting after school, those who did less than 4 hours a week, and those who did more than 4 hours a week.
Outcome measures: Body height without socks and shoes, body mass, and body composition were measured using a stadiometer, a digital flat floor scale, and bioelectrical impedance, respectively. SMM and BFM were determined and used to calculate the MFR. Seated grip strength was measured using a hand grip dynamometer on the right and left hands. In order to eliminate any outside strength variables, the humerus was positioned at the body’s side and arm was flexed 90 degrees. A two to three second squeeze was measured three times per hand and the highest reading was used for maximal handgrip strength. The grip-to-BMI ratio was calculated by dividing the maximal handgrip strength by BMI.
Sarcopenia risk diagnostics: Genders, age groups 4-9 and 10-14, and BMI quintile z-scores were separated to determine sarcopenia risk. If a child had 2SD lower than the mean MFR for the 3rd BMI quintile, then they were able to be diagnosed.
Statistics and data analysis: Kolmogorov-Smirnov testing was done to distribute data and variables between genders and age groups. Receiver-operating characteristic curves estimated the risk of sarcopenic obesity in children using the grip-to-BMI ratio. Children were categorized as excellent, good, fair, poor, and fail for each gender and age category by using the area under the curve to find cut off points and odds of developing sarcopenic obesity.
Results
Of the girls the median age was 9 and the boys was 8, and there was found to be significant differences between genders in age, height, weight, BMI, SMM, body fat percentage, BFM, and MFR. The cut off value for the 3rd BMI quintile was 1.22 kg/kg for girls and 1.35 kg/kg for boys. The area under the curve and cut off point respectively for girls age 4-9 was 0.791 and 0.680 kg/kg, for girls age 10-14 was 0.789 and 0.920 kg/kg, for boys age 4-9 was 0.719 and 0.721 kg/kg, and boys age 10-14 was 0.896 and 1.040 kg/kg. Using the grip-to-BMI ratio, the odds for at risk girls was 9.918 and the odds for at risk boys was 11.515.
Discussion
It is valuable information to be able to diagnose sarcopenic obesity without the pressures of cost and precise equipment. This study shows that using grip-to-BMI is a tool for identifying children at risk of being diagnosed with sarcopenic obesity. Different than adults with sarcopenia, children with obesity from lack of physical activity are developing sarcopenia, and obesity is increasing. When MFR decreases, muscle strength likely decreases, so using this factor to measure muscle strength is a good way to measure at risk children. When a child’s grip-to-BMI ratio was low, the odds of developing sarcopenic obesity were high. Overall this study shows that grip-to-BMI is an acceptable way to measure at risk children.
Limitations to this study include but are not limited to: the children used were from an active lifestyle event and may not represent Czech population as a whole, children may have been more active than others and produced better grip strength than children who were not active, difficulty finding the best cut off point can lead to false positives, differences in study comparisons based in Korea and the way they measured the risk, using electric signal to determine BMI always has estimations, and finally, there was no way to measure malnutrition, physical inactivity, or other underlying factors.
In conclusion, MFR is not a clinically acceptable way to diagnose sarcopenic obesity, but it is a quick and reliable way to find at risk children in need of further examination. Grip-to-strength was found to be able to discriminate between children at risk and those who were not. In the future, research should spread across more populations, but this study shows that this method can give children reason for detailed medical examinations, nutritional intervention, or implementation of exercise programing.
Application
This study is a great example of how advances in research pose a possibility for quick, easy, and cheap intervention of diseases that are affecting society today. Many programs have been launched to aim at decreasing the obesity epidemic, but as we all know, no program will ever have a 100% success rate. For this reason, an ability such as using hand grip strength to screen children in school for sarcopenic obesity can drastically change a child’s life as they age by implementing better nutrition and exercise programs. The key to all disease is prevention, and this article really shows that if places are willing to incorporate testing such as this, a better future can exist with healthier adults.
References
Steffl, M., Chrudimsky, .J,& Tufano, J.J. (2017) Using relative handgrip strength to identify children at risk of sarcopenic obesity. PLoS ONE 12(5). doi.org/10.1371/journal. pone.0177006
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