Limitations
There are some limitations to our
study which we need to emphasize. First, the cross-sectional nature of
our data implies that the characterization of the syncopal event,
personal and familiar history may be subject to recall bias, and this
may be particularly true for children participating in the survey. Yet,
we had a cohort of the general population of large dimensions, to which
we applied a digital-based questionnaire mainly composed of closed
questions and few open fields, thus enhancing our ability for complete
data collection. Second, our
questionnaire did not allow to establish a temporal relationship between
syncope and fever or the type or quantity of physical exercise since the
inclusion of such questions would have increased the complexity of the
questionnaire. Third, we studied a
young adult cohort with children and young-adults (<40
years-old), which included both athletes and non-athletes, therefore our
findings should only be applied to individuals belonging to these age
strata. Finally, despite the
clinical suspicion that individuals with US may be at an increased risk
for adverse cardiovascular events,
we
cannot make the definite diagnosis of cardiac syncope or directly infer
the risk of SCD based on our data, given the cross-sectional nature of
our study. We will be contacting some of the high risk-respondent
participants in the near future to perform further and more detailed
cardiovascular work-up, as well as a long-term follow-up.