Cold-Pressor Pain Responses in Healthy Opioid-Naive Males of Malay Ethnicity.

Objective: This study aimed to investigate cold-pressor test (CPT) over a 24 hour period in order to determine whether healthy opioid-naive Malay adult males exhibited any diurnal variation in their pain sensitivity. Design: This was a cross-sectional observational study conducted at the Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Malaysia. Materials and Methods: One hundred and fifty two healthy opioid-naive Malay adult males [mean age (SD) = 27.46 (10.10) years) who had given informed consent and had not suffered from any pain requiring analgesic medication within 72 hours of the CPT were entered into this study. Their pain-threshold, pain-tolerance and pain-intensity in response to the CPT were measured at 0, 2, 4, 8, 12, and 24 hours after the first CPT. Repeated measure analysis of variance was used to test for difference in diurnal variation of cold-pain responses. Results: There were no significant differences in diurnal variation of pain-threshold, pain-tolerance and pain-intensity scores in the studied population. Conclusion: The results indicated that healthy opioid-naive Malay adult males do not display significant diurnal variation to cold pressor pain sensitivity. [ABSTRACT FROM AUTHOR]