the ability to grip is one of the most important functions of the hand , and grip strength can be used to reflect overall muscular strength . several studies have shown that grip strength is inversely associated with all - cause mortality , functional impairments , frailty markers , cognitive impairments , physical disabilities , and nutritional status.[2 - 4 ] one example of using grip strength is the assessment of ' sarcopenia ' , which is characterized by progressive and generalized loss of skeletal muscle mass and strength with decreased physical performance . although lower extremity muscle strength is more relevant than upper extremity in terms of gait and physical function , grip strength has been widely used for assessing sarcopenia because it correlates well with lower extremity muscle strength . furthermore , grip strength measurement is simple and cost - effective . grip strength has been found to be associated with numerous factors such as demographics ( age , gender ) , body construct ( height , weight , bone mineral density [ bmd ] , hand size , upper arm circumference , hand dominance ) , socioeconomic variables ( occupation , social status , lifestyle ) and physical and psychosocial variables . furthermore , grip strengths significantly differ between ethnicities.[6 - 18 ] although there are a few studies that have assessed normative hand grip strength in koreans , few studies have looked at comprehensively those factors that potentially affect grip strength in a population - based cohort regarding elderly koreans . the aim of this study was to evaluate potential factors influencing grip strength in elderly koreans . this study was conducted as a substudy of the korean longitudinal study on health and aging ( klosha ) . the klosha was designed as a population - based prospective cohort study of health , aging , and common geriatric diseases in the elderly korean population , conducted from september 2005 to august 2006 , and involved residents of seongnam city , a satellite of metropolitan seoul , south korea . the institutional review board of the authors ' hospital approved this cohort - based study , and written informed consent was obtained from every participant . candidates were randomly drawn from a roster of patients 65 years or older using a computer - generated list of resident registration numbers . we invited 1,118 individuals to participate in this study by letter and telephone , of which 696 agreed to participate ( a response rate of 62.3% ) . a specially trained nurse recorded demographic data and conducted an interview , asking patients questions regarding a current or past medical history of illness or surgery . several questionnaires such as general health status , upper and lower extremity functions , cognitive function , depression etc . , were used at the point of enrollment . we excluded participants who had a history of trauma in the hand or wrist or prior surgery on the upper extremity . we also excluded those with symptoms of shoulder or elbow pain , and patients with rheumatoid arthritis . finally , 266 participants ( 143 males , 123 females ) were included in the analysis . the mean age of subjects was 71.7  4.4 years ( range , 65 - 87 years ) in men , 70.7  4.5 years ( range , 65 - 86 years ) in women . we evaluated grip strengths of the dominant hand in a standardized manner . in a neutral position of the arm , forearm , and wrist , 2 consecutive attempts with 1-minute intervalswere each measured in kilograms with a jamar 5030j1 hydraulic dynamometer ( sammons preston , bolingbrook , il , usa ) . factors assessed for potential association with grip strength were ; 1 ) demographics such as age and gender , 2 ) body constructs such as height , body mass index ( bmi ) , and bmd , 3 ) upper extremity functional status using disabilities of the arm , shoulder and hand ( dash ) scores , and 4 ) mental health status using a depression scale ( geriatric depression scale korean version , gds - k ) and the short form-36 ( sf36 ) mental health score.[23 - 25 ] height and body weight were measured by standard methods . bmi was calculated as weight in kilograms divided by the square of height in meters . the bmd ( g / cm ) of the lumbar spine ( l2-l4 ) and proximal femur was measured by dual - energy x - ray absorptiometry ( dxa ; model dpx , ge - lunar corp . , madison , wi , usa ) . all scans performed on the same machine by the same operator were analyzed with the same software . we used femur neck bmd for statistical analysis ; marin et al . reported that handgrip strength and lean mass were the variables that were best explained by femoral neck bmd . upper extremity functional status was assessed by using the korean version of the dash scores . dash is a self - administered , upper extremity - specific questionnaire and contains 30 items : 21 on physical function , 5 on symptoms , and 4 on social role functions . the dash has been widely used for evaluations of upper extremity functions , and is also well known for its reliability and validity . the dash provides overall scores ranged from 0 and 100 ( a best possible score of 0 and a worst possible score of 100 ) . mental health status was assessed using a depression scale ( gds - k ) and the sf36 mental health score . the gds - k , which is a standardized self - questionnaire scores ranging from 0 to 15 ( a score of 5 or more indicates depression ) were used to specifically assess the influence of depression . the sf36 is commonly used to represent broad aspects of patient - reported general health status , especially regarding musculoskeletal disorders . the thirty - six items in the questionnaire are grouped on eight health subscales , and these 8 scales can be combined into two summary measures that provide overall estimates of physical health ( physical component summary , pcs ) and mental health ( mental component summary , mcs ) . comparison of variables between male and female was tested by using student t - test . univariate analyses were performed initially between grip strength and potential factors , and then variables that were significant at p < 0.1 in the univariate analyses as well as those factors deemed clinically important were included in the multivariate analyses . multiple linear regression analyses with stepwise variable selection were used to assess the relative contributions of factors that influence the grip strength . multiple linear regression models assess the abilities of explanatory variables to account for variations in response variables while accounting for any confounding between explanatory variables , and produce a statistic called adjusted r , which reflects the percentage of overall variability in the dependant variable that can be explained by the explanatory variables included in a multiple linear regression model . , chicago , il , usa ) and statistical significance was accepted for p values of < 0.05 . this study was conducted as a substudy of the korean longitudinal study on health and aging ( klosha ) . the klosha was designed as a population - based prospective cohort study of health , aging , and common geriatric diseases in the elderly korean population , conducted from september 2005 to august 2006 , and involved residents of seongnam city , a satellite of metropolitan seoul , south korea . the institutional review board of the authors ' hospital approved this cohort - based study , and written informed consent was obtained from every participant . candidates were randomly drawn from a roster of patients 65 years or older using a computer - generated list of resident registration numbers . we invited 1,118 individuals to participate in this study by letter and telephone , of which 696 agreed to participate ( a response rate of 62.3% ) . a specially trained nurse recorded demographic data and conducted an interview , asking patients questions regarding a current or past medical history of illness or surgery . several questionnaires such as general health status , upper and lower extremity functions , cognitive function , depression etc . , were used at the point of enrollment . we excluded participants who had a history of trauma in the hand or wrist or prior surgery on the upper extremity . we also excluded those with symptoms of shoulder or elbow pain , and patients with rheumatoid arthritis . finally , 266 participants ( 143 males , 123 females ) were included in the analysis . the mean age of subjects was 71.7  4.4 years ( range , 65 - 87 years ) in men , 70.7  4.5 years ( range , 65 - 86 years ) in women . we evaluated grip strengths of the dominant hand in a standardized manner . in a neutral position of the arm , forearm , and wrist , 2 consecutive attempts with 1-minute intervalswere each measured in kilograms with a jamar 5030j1 hydraulic dynamometer ( sammons preston , bolingbrook , il , usa ) . for statistical analysis factors assessed for potential association with grip strength were ; 1 ) demographics such as age and gender , 2 ) body constructs such as height , body mass index ( bmi ) , and bmd , 3 ) upper extremity functional status using disabilities of the arm , shoulder and hand ( dash ) scores , and 4 ) mental health status using a depression scale ( geriatric depression scale korean version , gds - k ) and the short form-36 ( sf36 ) mental health score.[23 - 25 ] height and body weight were measured by standard methods . bmi was calculated as weight in kilograms divided by the square of height in meters . the bmd ( g / cm ) of the lumbar spine ( l2-l4 ) and proximal femur was measured by dual - energy x - ray absorptiometry ( dxa ; model dpx , ge - lunar corp . , all scans performed on the same machine by the same operator were analyzed with the same software . we used femur neck bmd for statistical analysis ; marin et al . reported that handgrip strength and lean mass were the variables that were best explained by femoral neck bmd . upper extremity functional status was assessed by using the korean version of the dash scores . dash is a self - administered , upper extremity - specific questionnaire and contains 30 items : 21 on physical function , 5 on symptoms , and 4 on social role functions . the dash has been widely used for evaluations of upper extremity functions , and is also well known for its reliability and validity . the dash provides overall scores ranged from 0 and 100 ( a best possible score of 0 and a worst possible score of 100 ) . mental health status was assessed using a depression scale ( gds - k ) and the sf36 mental health score . the gds - k , which is a standardized self - questionnaire scores ranging from 0 to 15 ( a score of 5 or more indicates depression ) were used to specifically assess the influence of depression . the sf36 is commonly used to represent broad aspects of patient - reported general health status , especially regarding musculoskeletal disorders . the thirty - six items in the questionnaire are grouped on eight health subscales , and these 8 scales can be combined into two summary measures that provide overall estimates of physical health ( physical component summary , pcs ) and mental health ( mental component summary , mcs ) . comparison of variables between male and female was tested by using student t - test . univariate analyses were performed initially between grip strength and potential factors , and then variables that were significant at p < 0.1 in the univariate analyses as well as those factors deemed clinically important were included in the multivariate analyses . multiple linear regression analyses with stepwise variable selection were used to assess the relative contributions of factors that influence the grip strength . multiple linear regression models assess the abilities of explanatory variables to account for variations in response variables while accounting for any confounding between explanatory variables , and produce a statistic called adjusted r , which reflects the percentage of overall variability in the dependant variable that can be explained by the explanatory variables included in a multiple linear regression model . , chicago , il , usa ) and statistical significance was accepted for p values of < 0.05 . the mean grip strength of dominant hand aged over 65 years was 27.7  7.3 kg in men , and 14.9  5.3 kg in women , and the difference was significant ( p < 0.001 ) . in addition , grip strength decreased continuously with further aging in both men and women , as expected ( table 1 ) . demographics and other variables assessed for the study subjects are summarized in table 2 . there were significant differences in height , weight , bmd , dash , gsd - k , and sf36-mcs scores between men and women ( table 2 ) . as many variables were found to differ between men and women , univariate and multivariate analyses were performed with separating the subjects into both sexes . univariate analyses demonstrated that age , height , weight , log bmi , bmd , dash , sf36-mcs , and gds - k were significantly associated with grip strength of the dominant hand in men . for women , age , height , weight , and bmd were found to be significantly associated with grip strength ( table 3 ) . in multivariate regression analyses , grip strength was found to be independently associated with age , height and bmi in men , and a model including these factors accounted for 21.3% ( adjusted r = 0.213 , p < 0.001 ) of the observed variability of grip strength . in women , grip strength was independently associated with age and height , and a model including these factors accounted for 19.7% ( adjusted r = 0.197 , p < 0.001 ) of the observed variability of grip strength ( table 4 ) . grip strength has been used as a measure of function in various health - related conditions . although grip strength is known to be affected by both physical and psychological factors , few studies have looked at those factors comprehensively in a population - based cohort regarding elderly koreans . this study demonstrates that in elderly koreans , grip strength is mainly influenced by age and height in both men and women , and additionally by bmi in men but not in women . bmd or self - reported physical or mental health status was not found to be associated grip strength in elderly koreans . there is a consensus that increasing age is inversely related with grip strength , and height correlates with grip strength . however , there are contradictory findings regarding association between grip strength and body weight or bmi . . found that among arthopometric data , grip strength was correlated best with height in both gender , and weight was associated in men , but not in women in caucasians . however , silventoinen et al . reported that grip strength is positively associated with height , weight , and bmi in both sexes in a study of one million swedish people . reported that there is age - related changes in body composition , particularly increases in fat and central fat deposition and decreases in lean mass , which may result in low skeletal muscle mass and obesity ( sarcopenic obesity ) . therefore , one can have a high bmi with weak muscle strength due to sarcopenic obesity . jang reported the prevalence of sarcopenic obesity is 35% in men and 48% in women in elderly koreans . high prevalence of sarcopenic obesity in women may explain why bmi was not found to be associated with grip strength in women in our study . it has been suggested that muscle strength may be positively related with higher bmd.[34 - 36 ] bayramolu et al . verified that the isometric strength of hip abductors had a significant correlation with femoral neck bmd in postmenopausal sedentary women with and without osteoporosis . marin et al . also found that grip strength in postmenopausal women was the one that best associated with bmd in all analyzed bone sites . in our study , however , grip strength was not associated with bmds . in this study , self - reported upper extremity functional status or mental health status was not found to be associated with grip strength . as we used self - administered questionnaires , we are not able to correlate grip strength with objective test results of physical and mental status . watson et al . investigated the relationship between grip strength and depression using the center for epidemiologic studies depression ( ces - d ) scale , pain anxiety symptoms scale , and pain catastrophizing scale . they reported that depression scores were minimally associated with decreased hand grip strength and that psychological factors influenced disability ( patient - reported health status ) more than function ( performance - based measures ) . in contrast , rantanen et al . demonstrated a stronger association between grip strength and depression using the ces - d scale . these authors examined grip strength data of 924 community - dwelling korean people aged over 65 years without dementia , and the mean grip strengths were 29 kg in men and 17 kg in women . grip strengths in koreans seem to be weaker compared to those in caucasians ( table 5 ) . previous studies found ethnic differences in grip strength in association with anthropometric differences,[41 - 43 ] and also withmuscle characteristics . first , our study focused on elderly koreans aged over 65 years , but included only small number of participants aged over 80 's ( 3.5% in men , 4.1% in women ) , which may not represent true elderly population . second , although we attempted to assess factors influencing grip strength comprehensively , we did not evaluate other factors such as hand size , upper arm circumference , occupation , lifestyle , medications , nutritional status , and other objective physical and mental status measures . lastly , this is a cross - sectional study , therefore associations found between grip strength and variables may not be causal . a longitudinal study with follow - up grip strength evaluations is required to generalize the findings of this study . in conclusion , we found in elderly koreans without a known history of upper extremity disorder or surgery , grip strength is independently associated with age and height in both gender , and with bmi in men . bmd or self - reported physical or mental health status was not found to be associated with grip strength . this information may be helpful in future studies using grip strength as a measure of function in elderly koreans .