Objectives: To determine whether pain tolerance and willingness to report pain is altered by RAS patients.
Methods: Data were collected at the University of Florida from June 2006-September 2007 through standardized questionnaires and oral exams using an unmatched case-control study. Participants included controls who never had RAS and 'active' (2+ RAS ≤3 months ago), 'inactive' (less than 2 RAS ≤3 months ago) or 'current' (with ulcers) cases who had not taken analgesics, anti-inflammatory or antipsychotic drugs for 24hrs. Participants rated tolerance and willingness to report pain using a visual analog scale (VAS; 0-10 cm). Data were analyzed using general linear models in SAS v9.2.
Results: Of 266 people screened, 50 were excluded, 27 withdrew, and 189 participants completed the study (80 controls and 109 cases). Participants were 17-56 years old (24±7 mean±S.D.), 57% Females, 15% Hispanic, 65% White, 9% Black, 6% Asian, 10% Indian, and 10% other/mixed race. Cases without aphthous ulcers were more tolerant to pain (VAS 6.8 vs. 6.2; p=0.042, adjusted for demographic factors) and cases with clinical aphthae were more willing to report pain (VAS 8.4 vs. 7.0; p=0.067) than controls. Gender and race were also linked to pain tolerance (adjusted p<0.001 and p=0.032, respectively), with females and Asians being less tolerant.
Conclusions: These results suggest that pain tolerance and willingness to report pain are related to RAS history. Further studies using standardized pain testing procedures are needed to determine the potential impact of RAS history on pain research studies. This research was supported in part by NIH grants R03DE016356, R21DE018714 and M01RR00082, and the contribution of CTSI personnel, research assistants, and study participants.