Sex differences in the associations among psychological factors and pain report: A novel psychophysical study of patients with chronic low back pain

Previous studies have consistently suggested that there are sex differences in pain report, but there is no consensus regarding sex differences in the associations among psychological factors and pain report. This cross-sectional study used a novel, clinically relevant, psychophysical pain-induction technique to examine sex differences between sensory and affective pain report and sex differences in the association of depression, pain related anxiety, and catastrophizing with pain report. Patients with chronic low back pain (N = 53) were recruited from an outpatient spine clinic, and those consenting completed self-report measures of pain-related anxiety, depression, pain catastrophizing, and pain. A measure of induced low back pain was obtained by having study participants perform a protocol on the MedX (TM) Low-Back Exercise Apparatus. Our results indicated that no sex differences were detected in psychological factors and self-reported or induced low back pain. However, the relationships between pain related anxiety and self-report of low back pain (z = 2.51, P <.05) and between pain-related anxiety and induced low back pain (z = 3.00, P <.05) were significantly stronger in men than women. These findings suggest that anxiety was linked to self-reported and induced low back pain for men, but not for women. Perspective: Results of this study suggest that pain-related anxiety has a stronger association with psychophysical and clinical reports of low back pain for men. (c) 2005 by the American Pain Society.