Association between muscle strength and type 2 diabetes mellitus in adults in Korea: Data from the Korea national health and nutrition examination survey (KNHANES) VI

Diabetes mellitus (DM) is a significant chronic disease, and health burden from DM is increasing. Recently, studies on the relationship between handgrip strength, which is a measuring tool for muscle strength, and type 2 DM were published. However, the results have been conflicting. In addition, few studies that used data from adults in Korea have been conducted. Thus, this study aimed to identify the association between handgrip strength as well as type 2 DM and insulin resistance in adults using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2014 to 2015. Inflammation is a condition affecting the muscle strength of individuals with type 2 DM; therefore, its mediating effects were also examined. We included 8208 participants aged between 19 and 80 years who had undergone a handgrip test and had received information about type 2 DM. General linear and binary logistic regression models were used to examine the association between handgrip strength and type 2 DM variables. In addition, mediation analysis was conducted to estimate the role of inflammation in the relationship between handgrip strength and type 2 DM. After adjusting for age, sex, education, alcohol consumption, lifetime smoking, obesity, and aerobic physical activity, handgrip strength was inversely associated with fasting glucose, HbA1c, and fasting insulin levels as well as the homeostasis model assessment of insulin resistance (HOMA-IR) score. Multivariable logistic regression analyses showed that handgrip strength was significantly inversely associated with type 2 DM and insulin resistance. The high-sensitivity C-reactive protein (hs-CRP), an inflammation-related biomarker, mediated approximately 10% of the association between handgrip strength and type 2 DM. Using large, well-defined, nationally representative cross-sectional data on adults in Korea, we found that handgrip strength, which is an indicator of muscle strength, was associated with type 2 DM.