Influences of Cardiovascular Fitness and Body Fatness on the Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis

Objective: The purpose of this meta-analysis was to investigate the associations between combined cardiovascular fitness, obesity, and the risk of metabolic syndrome. Data Sources: The MEDLINE and EMBASE databases were used to select relevant studies that included the relative risk (RRs) of metabolic syndrome based on the combined effects of cardiovascular fitness and obesity from January 1990 to July 2019. Study Inclusion and Exclusion Criteria: The inclusion criteria were providing the RRs for the associations between combined cardiovascular fitness and obesity and the risk of metabolic syndrome. The exclusion criteria were review studies, duplicated studies, and no RRs reported for those associations. Data Extraction: All selected studies categorized levels of cardiovascular fitness (high cardiovascular fitness vs low cardiovascular fitness) and obesity (normal vs obesity) and directly extracted the RRs for the risk of metabolic syndrome from these data. All selected studies were cross-sectional studies. Data Synthesis: All RRs and 95% CIs from the selected studies were computed to find the associations between combined cardiovascular fitness and obesity and the risk of metabolic syndrome. Results: A total of 8 studies were selected for this meta-analysis. Low cardiovascular fitness was associated with 3. Fifty-nine times increased metabolic syndrome risk regardless of obesity (3.59, 95% CI: 3.07-4.20; P = .00). And obesity was associated with 1.62 times increased metabolic syndrome risk regardless of cardiovascular fitness level (1.62, 95% CI: 1.32-1.98; P = .00). Lastly, the risk of metabolic syndrome decreased by 77% with high cardiovascular fitness regardless of obesity (0.23, 95% CI: 0.12-0.43; P = .00). Conclusions: The combined effects of cardiovascular fitness and obesity are important factors when determining metabolic syndrome risk. The minimum level of cardiovascular fitness is 8.39 metabolic equivalent (METs) for adults to lower the risk of metabolic syndrome. Enhanced cardiovascular fitness and maintaining normal weight should be recommended for individuals to reduce the risk of metabolic syndrome.