Effect of relative handgrip strength on cardiovascular disease among Korean adults aged 45 years and older: Results from the Korean Longitudinal Study of Aging (2006-2016)

Background: Aging causes both structural and functional changes in the skeletal muscle, and is associated with changes in body composition form, which results in an increased incidence of cardiovascular death. Handgrip strength (HGS) is a simple, fast, reliable, and cost-effective tool for measuring muscle strength. Objective: We aimed to investigate which index was most suitable for predicting cardiovascular disease (CVD), and suggested the optimal cut-off points based on the handgrip strength index. In addition, we aimed to identify the effects of weak HGS, as determined by applying the optimal cut point on the occurrence of CVD. Method: A total of 8494 older men and women aged over 45 years from the Korean Longitudinal Study of Aging (KLoSA) were included in this study at baseline. We performed general estimating equations (GEE) with independent correlation structure to assess whether handgrip strength is longitudinally related to occurrence of CVDs such as heart disease or stroke reported from 1 A to 6th wave of KLoSA. Results: The relative HGS was strongly associated with CVD in both sexes, and the best fit model was in that in comparison to dominant HGS and absolute HGS. In addition, we calculated the optimal cut point for CVD based on the relative HGS in this study (men: 2.52 and women: 1.55, respectively), and demonstrated that low HGS, as determined by applying relative HGS cut points, was associated with a higher OR for CVD compared to normal HGS; the associations observed were consistent between the sexes. Conclusions: Our findings suggest that HGS has the potential to be a valuable screening tool for cardiovascular risk in clinical settings; this is advantageous in situations where blood sampling is not possible since HGS is easily measured and highly reproducible. It is necessary to pay attention to weak grip strength against body size in the elderly population.