Obesity as a Mediator of the Influence of Cardiorespiratory Fitness on Cardiometabolic Risk: A Mediation Analysis

Abstract

OBJECTIVEThe relationship between cardiorespiratory fitness (CRF) and metabolic syndrome (MetS) is well known, although the extent to which body weight may act as a confounder or mediator in this relationship is uncertain. The aim of this study was to examine whether the association between CRF and cardiometabolic risk factors is mediated by BMI. RESEARCH DESIGN AND METHODSA cross-sectional study including 1,158 schoolchildren aged 8-11 years from the province of Cuenca, Spain, was undertaken. We measured height, weight, waist circumference (WC), blood pressure, fasting plasma lipid profile and insulin, and CRF (20-m shuttle run test). A validated cardiometabolic risk index was estimated by summing standardized z scores of WC, log triglyceride-to-HDL cholesterol ratio (TG/HDL-c), mean arterial pressure (MAP), and log fasting insulin. To assess whether the association between CRF and cardiometabolic risk was mediated by BMI, linear regression models were fitted according to Baron and Kenny procedures for mediation analysis. RESULTSIn girls, BMI acts as a full mediator in the relationship between CRF and cardiometabolic risk factors, with the exception of log TG/HDL-c ratio. In boys, BMI acts as a full mediator in the relationship between CRF and both log TG/HDL-c ratio and MAP, and as a partial mediator in the relationship between CRF and cardiometabolic risk factors. CONCLUSIONSBMI mediates the association between CRF and MetS in schoolchildren. Overall, good levels of CRF are associated with lower cardiometabolic risk, particularly when accompanied by weight reduction.

The influence of cardiorespiratory fitness on clustered cardiovascular disease risk factors and the mediator role of body mass index in youth: The UP&DOWN Study

“…Previous mediation analyses performed in children aged 8 to 11 years showed that the association between CRF and CVD risk factors was mediated by BMI in both sexes . Our results are in accordance, showing that 79.5%, 100%, 81.2%, and 55.7% of the total effect of CRF on CVDRF‐I in boys and girls children and adolescents, respectively, were mediated by BMI.…”

Adaptaciones al ejercicio físico en el perfil lipídico y la salud cardiovascular de obesos mórbidos

“…La capacidad cardiorrespiratoria aumentó significativamente en un 9.80%; importante variación, ya que esta se asocia con un menor riesgo cardiometabóli-co 27 . En estudios de 4 meses de duración con abordaje multidisciplinario, la distancia recorrida en el 6MWT se incrementó un 7.17% 28 .…”

Strength and cardiometabolic risk in young adults: The mediator role of aerobic fitness and waist circumference

“…Cardiorespiratory fitness (CRF) has been negatively associated with abdominal obesity and also with cardiometabolic risk, although it has been suggested that adiposity could mediate the relationship between CRF and cardiometabolic risk in children and adults . Moreover, although MS and CRF have been associated with cardiometabolic risk, studies assessing the independent role of each one have considered the other component of fitness as a confounder and therefore as a factor to be controlled in multivariate models …”