While we have attempted to thoroughly review available data and provide a broad estimate of population ranges, in some cases—particularly for nonreportable infectious diseases—these data are not available. Regional, temporal, and ethnic variations in prevalence among studies also limit the utility of calculated population rates in the context of a predominantly Caucasian population with a broad age range. In addition, the OCGAS medical questionnaire was limited to selected conditions and did not provide a comprehensive list of infectious, autoimmune, or inflammatory comorbidities. While conditions such as autoimmune thyroid diseases that are often difficult for patients to distinguish from nonautoimmune thyroid conditions without knowledge of laboratory testing were not included in this study, other categories such as encephalitis/meningitis were ambiguous with respect to etiology; although the vast majority of cases of meningitis are due to infection, approximately half of encephalitis cases may be autoimmune (Dubey et al. 2018).
