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

To explore the lifetime prevalence and correlates of syncope in the general population.

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).

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.

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.