Sex Differences in Associations of Cognitive Function with Perceptions of Pain in Older Adults.

Background: Sex differences in pain have been shown to exist in older adults with normal cognition and people with Alzheimer's disease. It is unknown if sex differences in pain in older adults exist in a range of communicative older adults with varying cognitive ability from no impairment to moderately severe cognitive impairment. Objective: This study proposes to compare the association between psychophysical responses to experimental thermal pain between males and females to determine if sex differences in pain exist across the cognitive spectrum. Methods: We conducted a secondary analysis of data from an age- and sex-matched between-groups cross-sectional study examining the psychophysical response to contact heat in people with and without dementia. Results: Median age of males (n = 38) and females (n = 38) was 73 (range: 68-87) with similar distributions of Mini-Mental State Examination (MMSE) scores (range: 11-30). Findings revealed inverse statistically significant associations with the threshold temperature of warmth (females: r = -0.41, p = 0.010; males: r = -0.33, p = 0.044). There was an apparent divergent pattern of MMSE associations with unpleasantness ratings between the groups. At the moderate pain threshold, that difference became statistically significant (p = 0 .033) . Females demonstrated a positive association of MMSE with unpleasantness (r= 0.30, p = 0.072), while males demonstrated an inverse association at that respective threshold (r = -0.20, p = 0.221). Conclusions: Between-group findings suggest that patterns of responses to thermal stimulus intensity may differ between males and females with worsening cognition with females reporting significantly less unpleasantness with the percept of moderate pain and males reporting significantly higher unpleasantness with moderate pain perception.