Relationship Between Grip Strength And All-cause Mortality In Middle-aged And Elderly People

ObjectiveThe purpose of this study was to explore the predictive value of grip strength for all-cause mortality in the middle-aged and elderly people through the study of the distribution characteristics of grip strength and of the association between grip strength,which aimed to provide references for health care measures such as physical improvement and health promotion of middle-aged and elderly people.MethodsThe study selected subjects aged 50 years and older,including 9633 from the CHARLS cohort and 26209 from the SHARE cohort.First,the baseline distribution characteristics of the survival group and the death group were compared and analyzed according to the survival status.Then the distribution of age and obesity status of grip strength were explored in the CHARLS and SHARE cohorts after adjusted for gender.In the third part,which intended to explore of the relationship between grip strength and all-cause mortality,the Kaplan-Meier method was used to calculate the mortality of grip strength in quintiles.Followed by the traditional Cox proportional hazard model were performed to calculate the hazard ratio(HR)of grip strength in quintiles.The shape of the relationship between grip strength and all-cause mortality was studied by incorporated grip strength as a continuous variable in the Cox regression model with penalize spline.To keep from the effect of missing data on the results,the sensitivity analysis was performed after filling in the missing data by multiple imputation method.All analyses were completed using R3.6.1 version,all hypothesis test levels a were taken as two-sided 0.05.Results1.The mean of grip strength in middle-aged and elderly males in the CHARLS cohort was 37.69±8.93kg,which was 25.52±7.12kg in females.The grip strength of males was higher than that of females(t=74.15,P<0.001).The mean grip strength of males in the SHARE cohort was 43.11 kg,which was 26.72kg of female and the gender difference was statistically significant(t=153.50,P<0.001).The grip strength decreased with aging,the decline of males in CHARLS cohort was 14.51kg,higher than that of females,which was 8.02kg.In the SHARE cohort,the decrease was 17.12kg of males,which was higher than 10.50kg of females.In CHARLS cohort,grip strength gradually decreased in obesity,overweight,normal weight and low-weight groups in both males and females(male:obese group:40.63kg;overweight group:40.20kg;normal group:37.02kg;low-weight group:32.43kg,P<0.001;female:obese group:26.78kg;overweight group:26.45kg;normal group:24.94kg;low-weight group:22.94kg,P<0.001).In the SHARE cohort,the difference between the grip strength of males in the overweight group and the obese group was relatively small,but they were both higher than that of low-weight group(obese group:44.40kg;overweight group:43.67kg;normal group:41.47kg;low-weight group:34.10kg);the difference of the females in obese group and low-weight group was statistically significant(obese group:26.81kg;overweight group:26.80kg;normal group:26.68kg;low-weight group:24.18kg).2.The all-cause mortality in the CHARLS cohort was 11.14%,which was 13.56%of males,and 9.01%of females.The all-cause mortality in the SHARE cohort was 7.52%,which was 8.86%of males and 5.45%of females.The results of the Cox proportional risk model of males were similar in these two cohorts and the risk of all-cause mortality in the Q5 group decreased by more than 50%(HR in CHARLS:0.40(0.22,0.71)vs HR in SHARE:0.46(0.34,0.63)),which in the other groups were relatively small(Q4 group:CHARLS:0.63(0.41,0.98);SHARE:0.56(0.44,0.71);Q3 group:CHARLS:0.63(0.44,0.91);SHARE:0.62(0.51,0.75);Q2 group:CHARLS:0.69(0.50,0.95);SHARE:0.71(0.60,0.84)).The results of Cox proportional risk model of females were inconsistent in these two cohorts.The Q5 group in SHARE cohort had a 54%decrease of mortality and the Q4 group had a 34%decrease,which were not statistically significant in CHARLS cohort.However,the Q3 group and Q2 group in the CHARLS cohort had stronger protection effect than in SHARE cohort(Q3:CHARLS:0.57(0.35,0.92)vs SHARE:0.73(0.58,0.92);Q2:CHARLS:0.62(0.40,0.96)vs SHARE:0.69(0.57,0.84)).3.The relationship between grip strength and all-cause mortality was linear in the CHARLS and SHARE cohorts.The HR of all-cause mortality in the CHARLS cohort was 0.82(0.84,0.92)of males and 0.85(0.79,0.91)of females;the HR in SHARE cohort was 0.88(0.84,0.92)of males and 0.85(0.79,0.91)of females.The sensitivity analysis results were consistent with the main results of this study(CHARLS male:0.84(0.78,0.90),CHARLS female:0.88(0.79,0.96);SHARE male:0.91(0.88,0.93),SHARE female:0.85(0.79,0.91)).Conclusions1.The grip strength of middle-aged and elderly people in China and Europe is declining with aging and the grip strength of males is generally higher than that of females,and grip strength in males decreased faster than females.The distribution of grip strength varies between different obesity status.2.The grip strength of middle-aged and elderly people is negatively correlated with the risk of all-cause mortality.When the grip value is higher,the risk of all-cause death is lower.Grip strength could be an important predictor of all-cause mortality in the middle-aged and elderly people.