EDITORIAL For reprint orders, please contact: [email protected]
Understanding the gender–pain gap
Osama A Tashani*1
Oras A Alabas1
Mark I Johnson1
“Over the last two decades, there has been an accumulation of strong evidence in support of differences in pain experiences between men and women.” Pain is an individual experience that is shaped by different biological, psychological and social factors. One biological factor is the sex of the individual according to anatomical, physiological and chromosomal characteristics. One psychosocial factor is the perception that an individual has of themselves as a woman or a man and how this influences the attitudes and behaviors in their daily life; in other words, their gender role. An individual’s gender role is known to influence attitudes and behaviors when in pain [1] . Sex and gender should not be used interchangeably in the context of pain behavior, and it is challenging trying to distinguish the contribution of sex or gender to pain response. The Consensus Working Group of the International Association for the Study of Pain (IASP) Special Interest Group on Sex, Gender and Pain recommended that the term ‘sex and gender’ should be used when comparing pain responses between women and men [2] .
Over the last two decades, there has been an accumulation of strong evidence in support of differences in pain experiences between men and women. The prevalence rates of many musculoskeletal pain conditions are higher among women than men [3] . Women are more likely to report severe and frequent pain [4] and experience multiple pains than men [5] . Studies on healthy human participants exposed to experimentally induced pain have been used to evaluate pain sensitivity response between men and women. Evidence for women being more sensitive to an experimental pain stimulus is less convincing [6] , with the interindividual variation larger than previously thought [7] . In laboratory settings, women show greater sensitivity to experimentally induced pain than men [8] , although the magnitude of the difference depends on the type of pain stimulus applied, how the pain measurements have been taken and
“We believe that women are more inclined to rate their pain, and the pain of others, higher because of their learned gender role and tendency to empathize more than men.”
Faculty of Health & Social Sciences, Leeds Metropolitan University, Leeds, UK *Author for correspondence: [email protected] 1
10.2217/PMT.12.34 © 2012 Future Medicine Ltd
Pain Manage. (2012) 2(4), 315–317
part of
ISSN 1758-1869
315
Editorial Tashani, Alabas & Johnson
“One of the challenges
of understanding the ‘gender–pain gap’ is the lack of valid animal models to study psychosocial aspects in pain.”
316
the size of the sample population [9] . In recent years, studies have investigated possible factors contributing to these interindividual variations, including several biological, psychological and social factors. To date, investigations into the biological factors responsible for sex and gender differences in pain response have focused on differences in reproductive physiology between women and men. Women have a more eventful reproductive physiological lifespan than men. In women, evidence to support a hormonal effect on sex and gender differences in pain response is largely based on increases in the prevalence and severity of some types of pain after puberty (e.g., temporomandibular disorder [10]) and menopause (e.g., headache [11]). On the other hand, after menopause, the secretion of some female hormones is reduced, and this increases the likelihood of the development of painful conditions such as fibromyalgia [11] and rheumatoid arthritis [12] . One psychosocial factor that may influence differences in pain sensitivity response is gender role. Traditionally, high levels of stoicism are related to men and high levels of sensitivity are related to women [13] . Recently, we have published a meta-analysis on gender role and response to experimental pain, which found that femininity was associated with lower pain threshold and tolerance. This supports the theory that learned masculinity encourages stoicism and encourages displays of withstanding pain. As expected, gender stereotypes specific to pain have stronger associations with sex and gender differences to painful stimuli than general masculine and feminine personality traits [14] . While our findings may not explain why there is a greater proportion of women presenting with clinical pain, it does show that genderassociated psychological attributes have a role in sex and gender differences. Thus, we believe that tools measuring the gender constructs of individuals in clinical and experimental pain research could lead to a better understanding of the factors contributing to differences in pain experience between women and men. We have also been interested in ethnocultural influences on the pain experiences of women and men. Interestingly, sex and gender differences in pain experience appear to be present in different ethnocultural groups. We found that sex and gender differences in response to cold pressor pain exist in non-western
Pain Manage. (2012) 2(4)
populations [15,16] . More importantly, gender role expectations of pain in Libyan university students were similar to white British students [14] . Sex and gender differences are documented across different ethnocultural groups despite significant differences in cultural beliefs between the studied groups. This suggests that a biological mechanism partly contributes to the phenomenon. A variety of psychometric tools have been used in sex and gender research to quantify pain catastrophizing and coping strategies, anxiety toward pain, stress and depression. Racine et al. reviewed the recent literature and concluded that catastrophizing, a cognitive-affective process that includes elements of magnification, helplessness, pessimism and rumination, has been shown to be strongly correlated with higher pain intensity ratings to experimental pain in women compared with men [17] . Surprisingly, depression or stress did not influence sex and gender differences in response to experimental pain. Recently, Ruau et al. analyzed the medical records of 11,000 patients in the USA and found that mean pain intensity rated on a 0 (no pain) to 10 (worst pain imaginable) scale was at least 1 point higher for women than men for a variety of painful conditions including neck, back and joint pain [18] . Authors of this study, however, noted that patients may rate pain differently based on the sex of the physician evaluating them. We believe that women are more inclined to rate their pain, and the pain of others, higher because of their learned gender role and tendency to empathize more than men. Women practitioners have been shown to care more than men about the pain of humans and animals [19,20] . To conclude, in the last decade research has shown that pain experience associated with the pathophysiology of a given condition is influenced by sex and by gender affecting the attitude and behavior of the individual. Age, physiological status and ethnicity also play a crucial role. One of the challenges of understanding the ‘gender–pain gap’ is the lack of valid animal models to study psychosocial aspects in pain. Those that exist have poor face validity. We think that the way forward in sex and gender differences in pain research is to study the pain responses in well-designed multidisciplinary experiments on different patients and general population groups.
future science group
Understanding the gender–pain gap Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes
References 1
2
3
4
Wandner LD, Scipio CD, Hirsh AT et al. The perception of pain in others: how gender, race, and age influence pain expectations. J. Pain 13(3), 220–227 (2012). Greenspan JD, Craft RM, LeResche L et al. Studying sex and gender differences in pain and analgesia: a consensus report. Pain 132(Suppl. 1), S26–S45 (2007). LeResche L. Defining gender disparities in pain management. Clin. Orthop. Relat. Res. 469(7), 1871–1877 (2011). Fillingim RB, King CD, Ribeiro-Dasilva MC et al. Sex, gender, and pain: a review of recent clinical and experimental findings. J. Pain 10(5), 447–485 (2009).
5
Berkley KJ. Sex differences in pain. Behav. Brain Sci. 20(3), 371–380 (1997).
6
Racine M, Tousignant-Laflamme Y, Kloda LA et al. A systematic literature review of 10 years of research on sex/gender and experimental pain perception – part 1: are there really differences between women and men? Pain 153(3), 602–618 (2012).
7
Fillingim RB. Individual differences in pain responses. Curr. Rheumatol. Rep. 7(5), 342–347 (2005).
future science group
Editorial
employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
8
Neziri AY, Scaramozzino P, Andersen OK et al. Reference values of mechanical and thermal pain tests in a pain-free population. Eur. J. Pain 15(4), 376–383 (2011).
15
Tashani OA, Alabas OM, Johnson MI. Cold pressor pain responses in healthy Libyans: effect of sex/gender, anxiety, and body size. Gend. Med. 7(4), 309–319 (2010).
9
Riley JL, Robinson ME, Wise EA et al. Sex differences in the perception of noxious experimental stimuli: a meta-analysis. Pain 74(2–3), 181–187 (1998).
16
Alabas OA, Tashani OA, Johnson MI. Gender role expectations of pain mediate sex differences in cold pain responses in healthy Libyans. Eur. J. Pain 16 (2), 300–311 (2012).
10
LeResche L, Mancl L, Sherman JJ et al. Changes in temporomandibular pain and other symptoms across the menstrual cycle. Pain 106(3), 253–261 (2003).
17
11
Cairns BE, Gazerani P. Sex-related differences in pain. Maturitas 63(4), 292–296 (2009).
Racine M, Tousignant-Laflamme Y, Kloda LA et al. A systematic literature review of 10 years of research on sex/gender and pain perception – part 2: do biopsychosocial factors alter pain sensitivity differently in women and men? Pain 153 (3), 619–635 (2012).
18
Ruau D, Liu LY, Clark JD, Angst MS, Butte AJ. Sex differences in reported pain across 11,000 patients captured in electronic medical records. J. Pain 13(3), 228–234 (2012).
19
Bertakis KD, Azari R. Patient-centered care: the influence of patient and resident physician gender and gender concordance in primary care. J. Womens Health (Larchmt) 21(3), 326–333 (2012).
12 Costenbader KH, Manson JE. Do female
hormones affect the onset or severity of rheumatoid arthritis? Arthritis Rheum. 59(3), 299–301 (2008). 13 Robinson ME, Riley JL, Myers CD.
Psychosocial contributions to sex-related differences in pain responses. In: Sex, Gender, and Pain. Fillingim RB (Ed.). IASP Press, Seattle, WA, USA, 41–68 (2000). 14
Alabas OA, Tashani OA, Tabasam G, Johnson MI. Gender role affects experimental pain responses: a systematic review with meta-analysis. Eur. J. Pain doi:10.1002/j.1532-2149.2012.00121.x (2012) (Epub ahead of print).
20 Serpell JA. Factors influencing human
attitudes to animals and their welfare. Anim. Welf. 13, S145–S151 (2004).
www.futuremedicine.com
317
Understanding the gender–pain gap
Osama A Tashani*1
Oras A Alabas1
Mark I Johnson1
“Over the last two decades, there has been an accumulation of strong evidence in support of differences in pain experiences between men and women.” Pain is an individual experience that is shaped by different biological, psychological and social factors. One biological factor is the sex of the individual according to anatomical, physiological and chromosomal characteristics. One psychosocial factor is the perception that an individual has of themselves as a woman or a man and how this influences the attitudes and behaviors in their daily life; in other words, their gender role. An individual’s gender role is known to influence attitudes and behaviors when in pain [1] . Sex and gender should not be used interchangeably in the context of pain behavior, and it is challenging trying to distinguish the contribution of sex or gender to pain response. The Consensus Working Group of the International Association for the Study of Pain (IASP) Special Interest Group on Sex, Gender and Pain recommended that the term ‘sex and gender’ should be used when comparing pain responses between women and men [2] .
Over the last two decades, there has been an accumulation of strong evidence in support of differences in pain experiences between men and women. The prevalence rates of many musculoskeletal pain conditions are higher among women than men [3] . Women are more likely to report severe and frequent pain [4] and experience multiple pains than men [5] . Studies on healthy human participants exposed to experimentally induced pain have been used to evaluate pain sensitivity response between men and women. Evidence for women being more sensitive to an experimental pain stimulus is less convincing [6] , with the interindividual variation larger than previously thought [7] . In laboratory settings, women show greater sensitivity to experimentally induced pain than men [8] , although the magnitude of the difference depends on the type of pain stimulus applied, how the pain measurements have been taken and
“We believe that women are more inclined to rate their pain, and the pain of others, higher because of their learned gender role and tendency to empathize more than men.”
Faculty of Health & Social Sciences, Leeds Metropolitan University, Leeds, UK *Author for correspondence: [email protected] 1
10.2217/PMT.12.34 © 2012 Future Medicine Ltd
Pain Manage. (2012) 2(4), 315–317
part of
ISSN 1758-1869
315
Editorial Tashani, Alabas & Johnson
“One of the challenges
of understanding the ‘gender–pain gap’ is the lack of valid animal models to study psychosocial aspects in pain.”
316
the size of the sample population [9] . In recent years, studies have investigated possible factors contributing to these interindividual variations, including several biological, psychological and social factors. To date, investigations into the biological factors responsible for sex and gender differences in pain response have focused on differences in reproductive physiology between women and men. Women have a more eventful reproductive physiological lifespan than men. In women, evidence to support a hormonal effect on sex and gender differences in pain response is largely based on increases in the prevalence and severity of some types of pain after puberty (e.g., temporomandibular disorder [10]) and menopause (e.g., headache [11]). On the other hand, after menopause, the secretion of some female hormones is reduced, and this increases the likelihood of the development of painful conditions such as fibromyalgia [11] and rheumatoid arthritis [12] . One psychosocial factor that may influence differences in pain sensitivity response is gender role. Traditionally, high levels of stoicism are related to men and high levels of sensitivity are related to women [13] . Recently, we have published a meta-analysis on gender role and response to experimental pain, which found that femininity was associated with lower pain threshold and tolerance. This supports the theory that learned masculinity encourages stoicism and encourages displays of withstanding pain. As expected, gender stereotypes specific to pain have stronger associations with sex and gender differences to painful stimuli than general masculine and feminine personality traits [14] . While our findings may not explain why there is a greater proportion of women presenting with clinical pain, it does show that genderassociated psychological attributes have a role in sex and gender differences. Thus, we believe that tools measuring the gender constructs of individuals in clinical and experimental pain research could lead to a better understanding of the factors contributing to differences in pain experience between women and men. We have also been interested in ethnocultural influences on the pain experiences of women and men. Interestingly, sex and gender differences in pain experience appear to be present in different ethnocultural groups. We found that sex and gender differences in response to cold pressor pain exist in non-western
Pain Manage. (2012) 2(4)
populations [15,16] . More importantly, gender role expectations of pain in Libyan university students were similar to white British students [14] . Sex and gender differences are documented across different ethnocultural groups despite significant differences in cultural beliefs between the studied groups. This suggests that a biological mechanism partly contributes to the phenomenon. A variety of psychometric tools have been used in sex and gender research to quantify pain catastrophizing and coping strategies, anxiety toward pain, stress and depression. Racine et al. reviewed the recent literature and concluded that catastrophizing, a cognitive-affective process that includes elements of magnification, helplessness, pessimism and rumination, has been shown to be strongly correlated with higher pain intensity ratings to experimental pain in women compared with men [17] . Surprisingly, depression or stress did not influence sex and gender differences in response to experimental pain. Recently, Ruau et al. analyzed the medical records of 11,000 patients in the USA and found that mean pain intensity rated on a 0 (no pain) to 10 (worst pain imaginable) scale was at least 1 point higher for women than men for a variety of painful conditions including neck, back and joint pain [18] . Authors of this study, however, noted that patients may rate pain differently based on the sex of the physician evaluating them. We believe that women are more inclined to rate their pain, and the pain of others, higher because of their learned gender role and tendency to empathize more than men. Women practitioners have been shown to care more than men about the pain of humans and animals [19,20] . To conclude, in the last decade research has shown that pain experience associated with the pathophysiology of a given condition is influenced by sex and by gender affecting the attitude and behavior of the individual. Age, physiological status and ethnicity also play a crucial role. One of the challenges of understanding the ‘gender–pain gap’ is the lack of valid animal models to study psychosocial aspects in pain. Those that exist have poor face validity. We think that the way forward in sex and gender differences in pain research is to study the pain responses in well-designed multidisciplinary experiments on different patients and general population groups.
future science group
Understanding the gender–pain gap Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes
References 1
2
3
4
Wandner LD, Scipio CD, Hirsh AT et al. The perception of pain in others: how gender, race, and age influence pain expectations. J. Pain 13(3), 220–227 (2012). Greenspan JD, Craft RM, LeResche L et al. Studying sex and gender differences in pain and analgesia: a consensus report. Pain 132(Suppl. 1), S26–S45 (2007). LeResche L. Defining gender disparities in pain management. Clin. Orthop. Relat. Res. 469(7), 1871–1877 (2011). Fillingim RB, King CD, Ribeiro-Dasilva MC et al. Sex, gender, and pain: a review of recent clinical and experimental findings. J. Pain 10(5), 447–485 (2009).
5
Berkley KJ. Sex differences in pain. Behav. Brain Sci. 20(3), 371–380 (1997).
6
Racine M, Tousignant-Laflamme Y, Kloda LA et al. A systematic literature review of 10 years of research on sex/gender and experimental pain perception – part 1: are there really differences between women and men? Pain 153(3), 602–618 (2012).
7
Fillingim RB. Individual differences in pain responses. Curr. Rheumatol. Rep. 7(5), 342–347 (2005).
future science group
Editorial
employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
8
Neziri AY, Scaramozzino P, Andersen OK et al. Reference values of mechanical and thermal pain tests in a pain-free population. Eur. J. Pain 15(4), 376–383 (2011).
15
Tashani OA, Alabas OM, Johnson MI. Cold pressor pain responses in healthy Libyans: effect of sex/gender, anxiety, and body size. Gend. Med. 7(4), 309–319 (2010).
9
Riley JL, Robinson ME, Wise EA et al. Sex differences in the perception of noxious experimental stimuli: a meta-analysis. Pain 74(2–3), 181–187 (1998).
16
Alabas OA, Tashani OA, Johnson MI. Gender role expectations of pain mediate sex differences in cold pain responses in healthy Libyans. Eur. J. Pain 16 (2), 300–311 (2012).
10
LeResche L, Mancl L, Sherman JJ et al. Changes in temporomandibular pain and other symptoms across the menstrual cycle. Pain 106(3), 253–261 (2003).
17
11
Cairns BE, Gazerani P. Sex-related differences in pain. Maturitas 63(4), 292–296 (2009).
Racine M, Tousignant-Laflamme Y, Kloda LA et al. A systematic literature review of 10 years of research on sex/gender and pain perception – part 2: do biopsychosocial factors alter pain sensitivity differently in women and men? Pain 153 (3), 619–635 (2012).
18
Ruau D, Liu LY, Clark JD, Angst MS, Butte AJ. Sex differences in reported pain across 11,000 patients captured in electronic medical records. J. Pain 13(3), 228–234 (2012).
19
Bertakis KD, Azari R. Patient-centered care: the influence of patient and resident physician gender and gender concordance in primary care. J. Womens Health (Larchmt) 21(3), 326–333 (2012).
12 Costenbader KH, Manson JE. Do female
hormones affect the onset or severity of rheumatoid arthritis? Arthritis Rheum. 59(3), 299–301 (2008). 13 Robinson ME, Riley JL, Myers CD.
Psychosocial contributions to sex-related differences in pain responses. In: Sex, Gender, and Pain. Fillingim RB (Ed.). IASP Press, Seattle, WA, USA, 41–68 (2000). 14
Alabas OA, Tashani OA, Tabasam G, Johnson MI. Gender role affects experimental pain responses: a systematic review with meta-analysis. Eur. J. Pain doi:10.1002/j.1532-2149.2012.00121.x (2012) (Epub ahead of print).
20 Serpell JA. Factors influencing human
attitudes to animals and their welfare. Anim. Welf. 13, S145–S151 (2004).
www.futuremedicine.com
317
