Relatively limited support is provided to the hypothesis that healthy women have greater pain sensitivity than men in most experimental pain modalities.
The purpose of this systematic review was to summarize and critically appraise the results of 10 years of human laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian and conducted in multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The first set of results (122 articles), which is presented in this paper, examined sex difference in the perception of laboratory-induced thermal, pressure, ischemic, muscle, electrical, chemical, and visceral pain in healthy subjects. This review suggests that females (F) and males (M) have comparable thresholds for cold and ischemic pain, while pressure pain thresholds are lower in F than M. There is strong evidence that F tolerate less thermal (heat, cold) and pressure pain than M but it is not the case for tolerance to ischemic pain, which is comparable in both sexes. The majority of the studies that measured pain intensity and unpleasantness showed no sex difference in many pain modalities. In summary, 10 years of laboratory research have not been successful in producing a clear and consistent pattern of sex differences in human pain sensitivity, even with the use of deep, tonic, long-lasting stimuli, which are known to better mimic clinical pain. Whether laboratory studies in healthy subjects are the best paradigm to investigate sex differences in pain perception is open to question and should be discussed with a view to enhancing the clinical relevance of these experiments and developing new research avenues.
aDepartment of Psychology, Université du Québec à Montréal, Montreal, Quebec, Canada
bCentre de recherche, Centre hospitalier de l’Université de Montréal (CRCHUM), Montreal, Quebec, Canada
cÉcole de réadaptation, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
dLife Sciences Library, McGill University, Montreal, Quebec, Canada
eDepartment of Family Medicine and Emergency, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
fResearch Centre, Montreal Heart Institute, Montreal, Quebec, Canada
gDepartment of Anaesthesiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
*Corresponding author at: Centre de recherche, Centre hospitalier de l’Université de Montréal (CRCHUM) − Hôtel-Dieu, Masson Pavilion, 3850 St. Urbain Street, Room 8-211, Montreal, Quebec, Canada H2W 1T7. Tel.: +1 514 890 8000x14082; fax: +1 514 412 7027.
Submitted February 15, 2011; revised November 15, 2011; accepted November 22, 2011.