Lifetime prevalence and correlates of syncope in five ancestry groups. The HELIUS study

Aim: To explore the lifetime prevalence and correlates of syncope in the general population. Methods: Through stratified random sampling, we included 14,937 White-European, Asian, Turkish, Moroccan, and West-African ancestry adults (18-70 y) in the cross-sectional Healthy Life in an Urban Setting (HELIUS) population study. We assessed syncope history by ancestry, and the potential correlates body mass index (BMI), systolic/diastolic blood pressure (SBP/DBP), resting plasma activity of creatine kinase (CK), the ATP-generating enzyme that facilitates cardiovascular contractility and sodium retention, and in a subgroup, supine cardiac contractility (dP/dt), cardiac output (CO) and systemic vascular resistance (SVR). Results: Mean age of the participants (39% men) was 43.3 y (SD12.9). Lifetime prevalence of syncope in women/men was respectively (%), White-European 42/24; Asian 34/19; Moroccan 32/16; Turkish 30/17; and West-African 20/14. Mean age at first syncope was 24 y (SD13). Participants with syncope history had lower SBP, DBP, BMI, CK, and modestly lower dP/dt and CO, but not SVR. In multivariable regression analysis, male sex (OR 0.52 [0.48 to 0.57]), West-African ancestry (0.59 [0.54 to 0.65]), and CK (0.56 [0.46 to 0.69]/log CK increase) were negatively associated with syncope. Conclusion: This study indicates that West-African ancestry, male sex, and high activity of the pressor enzyme CK are associated with lower syncope prevalence. These findings may inform further studies on the hemodynamics of syncope.