Positive additive interaction effects of age, sex, obesity, and metabolic syndrome on left ventricular dysfunction

OBJECTIVE: This study aims to explore the association between metabolic syndrome (MetS) and left ventricular diastolic dysfunction (LVDD) and systolic dysfunction (LVSD), defined by impaired global longitudinal strain (GLS), and assess additive and multiplicative interactions among age, sex, obesity, and MetS regarding LVDD and LVSD. METHODS: We prospectively recruited 5503 participants from the China PEACE (Patient-Centered Evaluative Assessment of Cardiac Events) Million Persons Project with complete echocardiography exam. Multivariable logistic models were used to calculate adjusted odds ratios to evaluate both additive and multiplicative interactions. RESULTS: The mean age was 56.59 years; 59.4% were women, 46.7% had MetS, 26.6% had left ventricular hypertrophy, 46.3% had LVDD, and 12.50% had impaired GLS. Compared to the non-MetS, the odds ratio (OR) of LVDD and impaired GLS in MetS were 1.40 (1.20-1.64) and 1.26 (1.03-1.54), respectively. For LVDD, relative excess risk due to additive interaction (RERI) for women and MetS, elderly and MetS, obesity and MetS were 0.76 (0.02-1.50), 35.65 (17.51-53.79), and 2.14 (0.66-3.62), respectively, thus suggesting additive interactions. For impaired GLS, RERI for obesity and MetS was 3.37 (0.50-6.24), thus suggesting additive interactions. CONCLUSIONS: The MetS is independently associated with LVDD and impaired GLS. From the public health implications, prevention of MetS in women, elderly, and obese individuals might result in a greater reduction of LVDD and LVSD risk in cardiovascular high-risk population.