The odds ratios in the multivariate analysis suggest that the prevalence of rhinosinusitis is more than twice as high in patients with BPPV than in people with normal vestibular function. This finding supports the findings in a previous report [4
]. The reason for this difference is unknown. Age, for which we adjusted, might be a factor. Physiologic factors might also be involved. This issue should be a fruitful area for future research.
The finding that otolaryngologists diagnosed sinus disease at a lower rate than the CT scan, alone, supports previous research showing that not all abnormalities found on CT scans indicate rhinosinusitis [10
]. This finding supports the need for expert clinical evaluation. The otolaryngologists had more data available than the radiologists, including a detailed history and physical examination. Furthermore, clinicians use clinical reasoning skills, including tacit knowledge of subtle cues about patient presentation [13
] that are important in diagnostic decision-making.
These data suggest that the frequency of sinonasal disease, in general, at least in the upper Texas Gulf coast vicinity, might be higher than indicated by the population-based survey data for the southern region [5
]. This difference highlights the value of testing individuals rather than relying on questionnaire data. Health histories may be inaccurate because people may remember or report their symptoms or histories inaccurately. Furthermore, regional differences in rhinosinusitis are well established. In the National Health Interview Survey, the prevalence rate was indeed higher in the South than in other regions. Smith et al. [16
] showed a similar finding from data on the number of ambulatory care visits, and they suggested that the increased prevalence may be due to higher rates of allergies and allergic fungal rhinosinusitis. In light of regional differences, differences in smaller localities within the region are also likely. Thus, near the Texas Gulf coast with exposure to the petrochemical industry, local molds and pollens, and almost constant, warm, humid weather, the local prevalence might be higher than other areas in the southern USA. These differences are important for planning health care resources by federal, state and local government authorities and health care providers.
Smith et al. [16
] and the National Health Interview Survey [5
] reported a higher rate of sinus disease in females than males. Our data confirm their findings. Other evidence, however, suggests no gender differences [16
]. Therefore, further research is needed to resolve this discrepancy. Women and men are known to report different symptoms of rhinosinusitis [17
]. The reasons for these differences remain unclear.
Our study adds some additional evidence to the observations of higher prevalence of sinonasal disease in patients with vestibular dysfunction. In this study, the diagnoses of vestibular dysfunction and sinonasal disease were clearly established, and the goal of the study was to evaluate this potential association. Prior studies used less stringent criteria for diagnosis or were secondary data analyses of data gathered for other reasons. Nevertheless, our study only identifies a cross-sectional association, and we cannot make assumptions about cause or effect based on that.
To postulate any causative mechanism in either direction (vestibular causing sinonasal, or sinonasal causing vestibular) would be difficult, since the possible mechanisms of a relationship between vestibular function and sinonasal inflammation are not clear. As a cofactor, however, sinonasal disease may cause more awareness of vestibular dysfunction or vice versa. This relationship needs further study. Our association did not reach statistical significance but it approached significance. A larger sample size may have yielded significant differences.