Impact of individual metabolic syndrome components on left ventricular diastolic function

Background Metabolic syndrome(MS) causes structural and functional changes in the heart. However, it is not well-known which component of MS affects the heart most severely. We aimed to investigate which parameter has the significant impact. Method This study analyzed data from 2433 adults aged 30 to 50 years who underwent echocardiography as part of a health check-up at our hospital between April 2020 and April 2025. Individuals with moderate or greater valvular regurgitation, mild or greater valvular stenosis, or a left ventricular ejection fraction (LVEF) of less than 50% were excluded. Results Overall, 19.7% (n=480) of the study population had MS. The mean age of the participants was 39.8 ± 5.1 years, and 28.4% were female. Among the diagnostic criteria for MS, the prevalence of hypertension was 34.7%, increased waist circumference 41.3%, hypertriglyceridemia 30.3%, low high-density lipoprotein cholesterol (HDL-c) 10.1%, and high blood glucose 16.2%. Consistent with previous research, significant structural and functional cardiac changes were observed in individuals with MS. Those with MS showed increased LV mass index (75.2 ± 13.7 vs. 71.6 ± 13.8 g/m²) and impaired diastolic function (e': 8.9 ± 2.0 vs. 10.3 ± 2.1 cm/sec, E/e': 7.1 ± 1.7 vs. 6.7 ± 1.4, p < 0.001). Individuals with high blood glucose exhibited lower e' (9.0 ± 2.0 vs. 10.3 ± 2.1 cm/sec, p < 0.01) and higher E/e' (7.2 ± 1.7 vs. 6.7 ± 1.4, p < 0.01). Similarly, those with hypertension had lower e' (9.3 ± 2.1 vs. 10.5 ± 2.1 cm/sec, p < 0.01) and higher E/e' (7.0 ± 1.7 vs. 6.6 ± 1.4, p < 0.01), and individuals with increased waist circumference also showed lower e' (9.3 ± 2.1 vs. 10.6 ± 2.1 cm/sec, p < 0.01) and higher E/e' (6.9 ± 1.6 vs. 6.7 ± 1.4, p < 0.01), indicating worsened diastolic function. While individuals with hypertriglyceridemia had significantly lower e' values (9.2 ± 2.1 vs. 10.4 ± 2.1 cm/sec, p < 0.01), there was no significant difference in E/e'. Similarly, those with low HDL-c had lower e' values (9.8 ± 2.2 vs. 10.1 ± 2.2 cm/sec, p < 0.05), but no significant difference in E/e'. Multiple linear regression analyses, including age, sex, and MS components, revealed that age, female sex, increased waist circumference, hypertension, and high blood glucose were significantly associated with an increase in E/e', while increased triglycerides and decreased HDL-c were not significantly associated. Conclusion Metabolic syndrome is associated with early structural and functional changes in the heart. Among the components of MS, increased waist circumference, hypertension, and high blood glucose significantly contribute to LV diastolic dysfunction, whereas hypertriglyceridemia and low HDL-c did not show a significant impact. For the long-term prevention of conditions such as heart failure, it is crucial to manage blood pressure, blood glucose, and obesity, in addition to improving the lipid profile.