BMC Sports Science, Medicine and Rehabilitation | 2021
The association between cardiorespiratory fitness, liver fat and insulin resistance in adults with or without type 2 diabetes: a cross-sectional analysis
Abstract
Background Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and\xa0reductions in liver fat\xa0content. However, there are limited data concerning the relationship between CRF and liver fat\xa0content in adults with varying degrees of metabolic dysfunction. Methods The aim of this study was to examine the association between CRF, liver fat\xa0content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional\xa0analysis. CRF was determined via a graded exercise test. Liver fat content was assessed via proton magnetic resonance spectroscopy and insulin resistance was assessed via homeostatic model of insulin resistance (HOMA-IR). A\xa0partial correlation analysis, controlling for age and gender, was performed to determine the association between CRF, demographic, cardiometabolic, and anthropometric variables. Independent t tests were performed to compare\xa0cardiometabolic outcomes between participants with T2D and participants without T2D. Results Seventy-two adults (46% male) with a mean age of 49.28\u2009±\u200910.8\u2009years, BMI of 34.69\u2009±\u20094.87\u2009kg/m 2 , liver fat content\xa0of 8.37\u2009±\u20096.90%,\xa0HOMA-IR of 3.07\xa0± 2.33 and CRF of 21.52\u2009±\u20093.77\u2009mL/kg/min participated in this study. CRF was inversely associated with liver fat content ( r \u2009=\u2009−\u20090.28, p \u2009=\u20090.019) and HOMA-IR ( r \u2009=\u2009−\u20090.40, p \u2009<\u20090.001). Participants with T2D had significantly higher liver fat content (+\u20093.66%, p \u2009=\u20090.024) and HOMA-IR (+ 2.44, p \xa0< 0.001)\xa0than participants without T2D. Participants with T2D tended to have lower CRF than participants without T2D (−\u20091.5\u2009ml/kg/min, p \u2009=\u20090.094). Conclusion CRF was inversely associated with liver fat\xa0content and insulin resistance. Participants with T2D had lower CRF than those without T2D, however, the difference was not statistically significant. Further longitudinal studies are required to elucidate the relationship between CRF and the progression of obesity-related diseases such as T2D. Registration: ACTRN12614001220651 (retrospectively registered on the 19th November 2014) and ACTRN12614000723684 (prospectively registered on the 8th July 2014).