Relationship Between Absolute Grip Strength And Relative Grip Strength With Metabolic Syndrome Among Adult Rural Residents

BackgroundMetabolic syndrome(MS)is a cluster of metabolic disorders including overweight and/or obesity,hypertension,dyslipidemia,and abnormal insulin resistance or glucose tolerance.In recent years,the incidence of MS has increased greatly worldwide,especially in developing countries.In 2005,the prevalence of MS was about 25%worldwide.In China,according to the analysis of chronic disease surveillance data in 2010,the prevalence of MS is as high as 30%;according to the results of a multi-center cross-sectional survey in 2019,the prevalence of MS,among adults≥20 years old,is 19.58%in the multi-ethnic population,and that is 19.91%in the Han population.The high prevalence indicates the grim situation of MS disease prevention and control in China.Each component of MS is the pathological basis of diabetes and cardio-cerebrovascular diseases.In addition,several studies have shown that MS is also associated with the risk of hyperuricemia and multiple cancer types such as pancreatic,colon,breast,prostate,and endometrial cancers.However,the current diagnosis and treatment of MS are still significantly inadequate.Therefore,it is of great significance to explore the influencing factors of MS,to identify MS patients early and intervene in time.The etiology and pathogenesis of MS are still unclear,but insulin resistance is believed to be the main mechanism of multiple metabolic abnormalities of MS.Skeletal muscles are primary sites for glucose uptake and deposition.The lack of muscle mass and strength are closely related with insulin resistance,which increasing the risk of diabetes and MS.Grip strength,as one of the most commonly used indicators to reflect muscle strength,is highly correlated with muscle strength in other parts of the body,and can effectively and reliably reflect the overall muscle strength.Roberts et al.published a systematic review showing that grip strength is a reliable and effective way to assess muscle strength among various measures of muscle strength.The measurement of grip strength is fast and easy to operate,and the measuring tool(grip strength meter)is economical and portable.In addition,previous studies have found that grip strength is strongly associated with the risk of cardiovascular disease,cancer,and all-cause death,which indicate grip strength can be used as a predictor of a variety of diseases.Grip strength can be evaluated by absolute and relative indicators.Absolute grip strength is the value measured by the grip meter,which reflects the absolute strength of the body.Relative grip strength can be measured by absolute grip strength/body mass index(BMI)or absolute grip strength/weight,reflecting the relative strength of the body.Currently,a number of studies have investigated the relationship between absolute or relative grip strength and the risk of MS.However,the relationship between absolute grip strength and MS remains controversial.Only few studies have focused on the relationship between relative grip strength(absolute grip strength/weight)and the risk of MS,and most of these studies focused on the elderly.In addition,depending on the use of absolute or relative grip strength,the relationship between grip strength and metabolic syndrome may conflict,which needs to be further explored.In this context,it is of important public health significance to assess the association between absolute grip strength and relative grip strength(absolute grip strength/weight)and the risk of MS in adult residents.ObjectivesBased on baseline data of the Shandong Hilly Rural Cohort collected from October 2017 to October 2019,the objectives of this study were to explore the relationship between absolute grip strength and relative grip strength(absolute grip strength/weight)with the risk of metabolic syndrome(MS),to assess and compare the predictive values of absolute grip strength and relative grip strength(absolute grip strength/weight)in the diagnosis of MS and its components,and to provide a theoretical basis for the early identification and comprehensive prevention of MS risk factors.Subjects and MethodsThe Shandong Hilly Rural Cohort was established in 39 villages in Pingyin County,Jinan City.The baseline data of this cohort study was collected from October 2017 to October 2019.With the electronic structured questionnaire,investigators face-to-face interviewed the participants to collect information on general demographic characteristics and other related variables.At the same time,the anthropometric measurements and blood biochemical test were conducted.Anthropometric measurements indicators included absolute grip strength,height,weight and blood pressure.Blood biochemical indicators included fasting plasma glucose(FPG),triglycerides(TG)and high density liptein cholesterol(HDL-C).Finally,this study used the data of 3997 adult residents aged 18 to 80 years with complete information on grip strength indicators and MS related indicators.MS was defined according to the standards of Diabetes Society of the Chinese Medical Association.Patients with≥3 of the following 4 characteristics were considered to have MS:(1)overweight and/or obese:BMI≥25.0 kg/m2;(2)Hypertension:patients with systolic blood pressure(SBP)/diastolic blood pressure(DBP)≥140/90 mm Hg and/or confirmed hypertension and receiving treatment;(3)dyslipidemia:TG≥1.7mmol/L and/or HDL-C≤0.9mmol/L(in the males)or≤1.0mmol/L(in the females);(4)Hyperglycemia:patients with FPG≥6.1mmol/L and/or 2h postprandial blood glucose≥ 7.8mmol and/or diagnosed with diabetes and receiving treatment.Due to gender differences in grip strength and MS prevalence,the analysis was conducted by gender stratification in this study.The correlation between absolute grip strength and relative grip strength(absolute grip strength/weight)and MS components was analyzed by Pearson correlation or Spearman correlation.The trend of prevalence of MS and its components with the level of grip strength was investigated by using the trend χ2 test,and the relationship between grip strength and the risk of MS was analyzed by logistic regression model.Receiver Operating Characteristic Curve(ROC)was used to analyze and compare the diagnostic value of absolute grip strength and relative grip strength(absolute grip strength/weight)for MS and its components,and the optimal cutoff value of grip strength was calculated by Youden Index.Two-sided test was used for all statistical analyses,and the test level was α=0.05.ResultsThe prevalence of MS among adult rural residents in Pingyin County was 18.7%(18.15%for males and 18.97%for females).Correlation analysis results showed that the absolute grip strength was positively correlated with BMI,DBP and TG(P<0.001)among males,and was negatively correlated with SBP and HDL-C(P<0.05),while relative grip strength was positively correlated with HDL-C(P<0.001),and negatively correlated with BMI,SBP,TG and FPG(P<0.001).Among females,absolute grip strength was positively correlated with BMI(P<0.001),and negatively correlated with SBP,HDL-C,and FPG(all P<0.01),while relative grip strength was positively correlated with HDL-C(P<0.001),and negatively correlated with BMI,SBP,DBP,TG,and FPG(all P<0.001).The trend of chi-squared test showed that with the increase of absolute grip strength,the prevalence of MS,overweight and/or obesity,and dyslipidemia among males increased,and the prevalence of hypertension decreased(all P<0.05),while among females the prevalence of overweight and/or obesity increased,and the prevalence of MS,hypertension and hyperglycemia decreased(all P<0.01).The prevalence of MS,overweight and/or obesity,hypertension,dyslipidemia,and hyperglycemia in both males and females decreased with increased relative grip strength(all P<0.001).After adjusting for age,education level,smoking,drinking,physical activity,family history of cardiovascular disease,family history of hypertension,family history of hyperlipidemia,family history of diabetes,multivariable logistic regression(model 3)showed that participants in the highest quartile group had greater risk of overweight and/or obesity(Odds ratio was 2.34 for males and 1.90 for females,P<0.05)than those in the lowest quartile group of absolute grip.In addition,the risk of MS,overweight and/or obesity,hypertension,dyslipidemia,and hyperglycemia of participants in the highest quartile group were 0.16 and 0.19 times,0.12 and 0.09 times,0.51 and 0.42 times,0.25 and 0.48 times,0.36 and 0.55 times than that in the lowest quartile group for males and females,respectively(all P<0.05).When diagnosing MS,the area under the ROC curve(AUC)of absolute grip strength was 0.434 and 0.542 for male and female,and the AUC of relative grip strength was 0.626 and 0.674 for female,respectively.The diagnostic value of relative grip strength was better than that of absolute grip strength.Based on the Youden Index,the best cutoff value of relative grip strength in diagnosing MS was 58.5(in the males)and 40.8(in the females).Conclusions1.Absolute grip strength was only associated with the risk of overweight and/or obesity,and was not associated with the risk of MS,hypertension,dyslipidemia or hyperglycemia.2.The relative grip strength was significantly inversely associated with MS and its separate components.It can be used as a screening indicator for MS.3.According to ROC curve analysis,relative grip strength was better than absolute grip strength in the diagnosis of MS and its components,but AUC was less than 0.7,indicating low accuracy.4.The optimal cutoff value of relative grip strength for the diagnosis of MS was 58.5 in the males and 40.8 in the females.