Satisfaction with Sex and Erection Hardness: Results of the Asia-Pacific Sexual Health and Overall Wellness Survey

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ORIGINAL ARTICLE Satisfaction with sex and erection hardness: results of the Asia-Pacific Sexual Health and Overall Wellness survey

R King1, K Marumo2, J-S Paick3, K Zhang4, R Shah5, W Pangkahila6,AW-CYip7, B-P Jiann8 and M-L Ong9

1Sydney Centre for Sexual and Relationship Therapy, Sydney, NSW, Australia; 2Department of Urology, Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan; 3Department of Urology, College of Medicine, Seoul National University, Seoul, Korea; 4Department of Urology, Peking University First Hospital, Beijing, China; 5Lilavati Hospital and Research Center, Mumbai, India; 6Department of Andrology and Sexology, Udayana University, Bali, Indonesia; 7Department of Surgery, Kwong Wah Hospital, Kowloon, Hong Kong; 8Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan and 9Pfizer Inc, New York, NY, USA

The Asia-Pacific Sexual Health and Overall Wellness (AP SHOW) survey assessed sexual satisfaction and health and the association with erection hardness in 13 Asia-Pacific countries/ regions. Adults aged 25–74 years who had sexual intercourse X1 time in the past 12 months answered Internet surveys or participated in street-intercept interviews. Data were weighted by demographics and country/region size. Of 3957 (men, n ¼ 2016 and women, n ¼ 1941) respondents, 41% of men and 34% of women were completely or very satisfied with sex. Satisfaction with sex was linked to satisfaction with life priorities and overall health. Few respondents (men, 38% and women, 26%) were very or completely satisfied with erection hardness. Optimal erection hardness was reported by 45% of men (48% of women regarding their partners’ erections). Erection hardness was associated with increased frequency of sex and importance of and satisfaction with erection- related elements of men’s sexual performance. Approximately half of respondents (men, 57% and women, 47%) were at least moderately interested in improving the sexual experience. Most Asia- Pacific respondents were less than very satisfied with sex. Satisfaction with sex was associated with satisfaction with life priorities. Erection hardness was associated with sexual satisfaction and activity, satisfaction with life priorities and overall health. International Journal of Impotence Research (2011) 23, 135–141; doi:10.1038/ijir.2011.17; published online 16 June 2011

Keywords: hardness; health; penile erections; personal satisfaction; sexual behavior

Introduction with erection hardness.3 A recent retrospective analysis of data from 26 randomized controlled Sexual health is important to overall health and well trials demonstrated that improved erection hardness being. In a global study of middle-aged and older correlated with significant improvements in sexual adults in 29 countries, the frequency of experiencing intercourse enjoyment, sexual relationship satisfaction sexual problems correlated inversely with the and confidence in erections for satisfactory sexual degree of satisfaction with sexual life among men activity.4 In studies and surveys of men with erectile and women.1 dysfunction (ED), improvement in a man’s erectile Successful sexual intercourse is directly related to function enhances the emotional well being and erection hardness.2 Sexually active men and women quality of life for both partners.5–9 who are satisfied with erection hardness are more Erectile function is not typically examined out- satisfied with their sex life, love and romance and side of the clinical trial setting of patients with ED; overall health than those who report low satisfaction although erection hardness has been a component of such studies, it has not been the focus. Cultural differences can influence the sexual experience. The Asian population, in particular, has been reported Correspondence: Dr B-P Jiann, Department of Surgery, to be more conservative regarding sex, more Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st 10 Rd, Kaohsiung, Taiwan 81346 ROC, Taiwan. male-oriented and less sexually active. Although E-mail: [email protected] Japanese men in a community-based survey Received 4 November 2010; revised 10 March 2011; reported more problems with sexual functioning accepted 22 April 2011; published online 16 June 2011 and decreased libido compared with American men, Asia-Pacific sexual health survey R King et al 136 perceived sexual satisfaction did not differ between Comparisons were made between four groups of these populations.11 A study of Chinese couples respondents according to their Erection Hardness from Hong Kong noted several culturally unique Score (EHS). The EHS is a validated, self-reported findings that contrast with observations in Western measure that classifies erection hardness on societies, such as the thought that education level, a single-item scale.15 Scores describe the most income and years of marriage are unrelated to sexual frequent penile erection hardness achieved by the satisfaction.12 Qualitative differences have been respondent/respondent’s partner during sexual noted within Chinese society; housewives from activity, ranging from 1–4 (1 ¼ penis is larger, but mainland China and those from Hong Kong reported not hard; 2 ¼ penis is hard, but not hard enough for differences in sexual expectations.13 However, penetration; 3 ¼ penis is hard enough for penetra- changing sexual perceptions and behaviors of Asian tion, but not completely hard; 4 ¼ penis is comple- populations have been suggested.14 The Asia-Pacific tely hard and fully rigid). Respondents having EHS Sexual Health and Overall Wellness (AP SHOW) grade 3 were considered to have suboptimal erection survey was performed to assess sexual satisfaction hardness; those having EHS grade 4 were considered and health and the association with erection hard- to have optimal erection hardness.15 ness in the general population of the Asia-Pacific region.

Subject recruitment Different methods of sampling were used because of Subjects and methods local research capabilities and the highly personal subject manner. In Australia, New Zealand, Singapore, Survey details Hong Kong, Taiwan, Indonesia, Malaysia, Philip- A panel of six of the authors participated in the pines, Japan and South Korea, all interviews were design of the study and the development of the male conducted using an online self-administered survey. and female questionnaires. The seven survey E-mail invitations to online panelists who were sections assessed personality profile and life accustomed to completing electronic surveys were priorities, love/intimate relationship, attitudes randomly generated. In India, China and Thailand, about sex, sexual relationship/experience (including all interviews were conducted face-to-face during important elements associated with a good sexual random street intercepts in large cities. Interviewers experience), men’s sexual health and performance, selected busy street intersections and shopping health profile and demographics. areas, randomly stopping passing men and women All surveys were conducted in local languages. to ask for their participation in the survey. Inter- An English survey was first translated into the viewers handed respondents a self-administered appropriate local language(s) by an independent paper questionnaire to complete and provided professional translation agency; the initial transla- assistance if needed. tion then was validated by another independent Subjects included men and women aged 25 to 74 translation agency. Proofreading against the English years who had sexual intercourse at least once in the original was performed and changes/corrections past 12 months. Female respondents had to have were made if needed. Validation was undertaken sexual intercourse with a member of the opposite to assure that the essence of the English original was sex. captured in the local language(s) and that all questions and answer options were understandable to respondents in each country/region. Question- naires were intentionally designed to use simple, Statistical analysis straightforward language, free of medical or specia- Findings were based on data from all 13 Asia-Pacific lized terminology. Many of the questions phrases regions combined. To provide a weighted total of the used in the survey were used, tested and validated 13 countries, data from each country were weighted in a previous 27-country survey.3 in two steps. The initial weighting was to the Non-ordinal rating scales were used for many country’s standard demographic parameters (includ- questions in the survey and the top two box ratings ing gender, age, region and education) to reduce the were used to report data. The Importance Scale effects of any sampling and/or selection bias and included responses of absolutely essential, very to ensure representativeness within each given important, important, somewhat important and not country. Weighting by the country’s population at all important; responses of absolutely essential size was performed next to accurately reflect the and very important were used for reporting. The proportional differences in population size between Satisfaction Scale included responses of completely countries in the Asia-Pacific region. Specifically, satisfied, very satisfied, satisfied, somewhat satis- countries with smaller populations were down- fied and not at all satisfied; responses of completely weighted, whereas countries with larger popula- satisfied and very satisfied were combined. tions were upweighted. Unweighted bases for men

International Journal of Impotence Research Asia-Pacific sexual health survey R King et al 137 and women are displayed in figure legends to reflect for women. The complete rankings for men (ordered the true sample size. from highest to lowest priority) were family life, Statistical significance at the 95% confidence physical health, being a spouse/partner, financial level was tested using a two-sided Student t-test well being, being a parent, work/career, sex, on column means and a z-test for proportions. physical activity, gaining wisdom, social life, leisure Statistical significance was declared when Po0.05. time, love/romance, prestige, spirituality, hobbies/ The overlap method was automatically applied by interests, community involvement and religious the software (Quantumt v5.7, SPSS, Chicago, IL, activities. For women, rankings were family life, USA) where applicable. physical health, being a spouse/partner, being a parent, financial well being, work/career, spirituality, social life, leisure time, gaining wisdom, Results physical activity, love/romance, hobbies/interests, community involvement, prestige, sex and religious activities. Respondent characteristics More men than women (55% versus 36%; The Asia-Pacific Sexual Health and Overall P 0.0001) thought sex was absolutely essential or Wellness (AP SHOW) survey assessed 3957 sexually o very important. The proportion of men who thought active men (n ¼ 2016) and women (n ¼ 1941) in 13 sex was absolutely essential or very important was countries and regions from May through July 2008. lowest in Thailand (29%) and highest in the Demographic information is presented in Table 1. Philippines (79%); the range for women was 19% Respondents were mostly aged 59 years or younger (Thailand) to 60% (New Zealand) (Table 3). (p8% of men and women aged 460 years). Significantly more women than men were married (Po0.0001). Conversely, significantly more men Table 2 Number of interview participants by country in the than women were single, never married; divorced, Asia-Pacific Sexual Health and Overall Wellness Survey separated or widowed; or living with a partner. Data by region are summarized in Table 2. Country Men, n Women, n Language Response rates ranged from 7% (Philippines and Australia) to 42% (Singapore) for surveyed countries Australia 101 108 English using online panelists; response rates could not be China 100 110 Simplified Chinese determined for those in which street intercepts were Hong Kong 117 106 Traditional Chinese India 115 115 English used (India, China and Thailand). Indonesia 100 100 Bahasa Indonesia Japan 328 250 Japanese South Korea 102 100 Korean Malaysia 100 100 Malay Importance of sex New Zealand 100 100 English When ranking the importance of life priorities from Philippines 205 202 Tagalog/English a list of 17 items, sex ranked 7th for men and 16th Singapore 148 150 English Taiwan 300 300 Traditional Chinese Thailand 200 200 Thai

Table 1 Demographic profile of surveyed population

Men, Women, Table 3 Country/region-specific responses to survey questions %(n ¼ 2016) %(n ¼ 1941) Country Percentage Percentage Percentage reporting sex ‘completely’ reporting Age (years) as ‘absolutely or ‘very’ EHS o40 49 49 essential’ or satisfied 4:3:2:1 40–59 43 45 ‘very important’ with sex X60 8 7 Men Women Men Women Men Women Marital status Married 83 93 Living with a partner 6 2 Australia 70 53 40 40 68:26:2:4 66:20:11:3 Single, never married 9 3 China 39 22 25 21 55:25:9:11 55:20:16:8 Divorced, separated 41Hong Kong 56 40 34 31 52:34:9:5 40:41:14:5 India 75 57 73 65 51:21:12:15 39:30:14:17 or widowed Indonesia 72 46 36 24 70:20:8:3 81:14:3:1 Japan 50 20 10 4 54:35:5:6 53:39:5:3 Employment status South Korea 66 35 19 11 57:32:6:4 50:40:5:5 Employed full-time 65 42 Malaysia 64 45 38 27 60:34:4:3 77:18:3:2 Employed part-time 4 8 New Zealand 62 60 41 46 64:36:0:1 67:23:6:4 Self-employed 20 13 Philippines 79 53 54 46 67:27:1:5 67:18:15:0 Not employed 2 1 Singapore 60 59 34 37 54:29:16:1 48:33:12:7 Retired 9 13 Taiwan 73 52 53 38 52:28:10:10 53:25:22:0 Homemaker 0 23 Thailand 29 19 30 16 70:20:6:4 58:25:12:5

International Journal of Impotence Research Asia-Pacific sexual health survey R King et al 138 Overall, men in the Asia-Pacific region placed Satisfaction with sex was positively related to higher levels of importance on almost all measured overall health. For men, 53% of those who reported aspects of the sexual experience than women. More themselves as very or completely satisfied with sex than 50% of men ranked the ability to achieve reported their overall health status as excellent or climax, intercourse and physical foreplay as abso- very good, compared with 19% of those who were lutely essential or very important to having a good somewhat or not at all satisfied with sex. For sexual experience. For women, 42% of women women, 41% of those who reported themselves as ranked physical foreplay as absolutely essential very or completely satisfied with sex reported their or very important, whereas 39% ranked feeling overall health status as excellent or very good, attracted to their partner similarly. compared with 11% of those who were somewhat or not at all satisfied with sex.

Satisfaction with sex Overall, less than half of all respondents (41% of Satisfaction with erection hardness and relation to men and 34% of women) reported being completely satisfaction with sex and life priorities or very satisfied with sex; satisfaction varied For men, the percentage of respondents who were between regions, but was lowest in Japan (10% very satisfied or completely satisfied with erection of men and 4% of women) and highest in India hardness was 38% and for women, it was 26%. (73% of men and 65% of women Table 3). Greater A strong association was found between reported levels of satisfaction with sex were strongly asso- satisfaction with all measured aspects of the sexual ciated with greater levels of satisfaction with experience and reported satisfaction with erection aspects of life that were ranked highly important hardness for both men (Figure 2a) and women by men (Figure 1a) and women (Figure 1b;Po0.0001 (Figure 2b;Po0.0001 for all). A strong association for all). between satisfaction with erection hardness and

Figure 2 Relationship of satisfaction with erection hardness and Figure 1 Relationship of satisfaction with sex and satisfaction satisfaction with specific aspects of sexual function in men with life priorities in men (a) and women (b). Respondents (a) and women (b). Participants were asked, ‘How satisfied are were asked, ‘How satisfied are you with each aspect of your you with each aspect of your relationship?’ and ‘How satisfied are life?’ Men who were very/completely satisfied with sex (n ¼ 721) you with the hardness of your (for women, your partner’s) and those who were somewhat/not at all satisfied with erection?’ Men and women who were very/completely satisfied sex (n ¼ 494) and women reporting the same responses (n ¼ 600 with erection hardness (n ¼ 840 and 635, respectively) and those and 516, respectively) were the basis for the percentages who were somewhat/not at all satisfied (n ¼ 379 and 425, displayed. respectively) were the basis for the percentages shown.

International Journal of Impotence Research Asia-Pacific sexual health survey R King et al 139 satisfaction with some of the most important life during intercourse (Figure 4); this relationship was priorities was observed for both men (Figure 3a) and observed in all regions analyzed. Satisfaction with women (Figure 3b; Po0.0001 for all). In regions erection hardness was associated with greater with sufficient sample sizes for analysis (Japan, frequency of sex. Men who were completely or very South Korea, China and Indonesia), greater levels of satisfied with their erection hardness reported satisfaction with erection hardness were strongly having significantly more sex in the preceding associated with greater levels of satisfaction with month than men who were somewhat or not at all sex among both men and women. satisfied with their erection hardness (means of 9.3 versus 4.5 times, respectively; Po0.0001). This pattern was observed in South Korea, China and Indonesia, but not in Japan; sample sizes in other Erection Hardness Score regions were too small to provide meaningful Optimal erection hardness (EHS 4) during sexual comparisons. Similarly, women who were comple- activity was reported by 55% of men and 52% of tely or very satisfied with the hardness of their women. At least 50% of men and 39% of women in partner’s erection reported having significantly more every country reported EHS 4 erections (Table 3). sex in the preceding month than women who were Overall, 24% of men reported their erections as somewhat or not at all satisfied with the hardness of EHS 3, 9% as EHS 2 and 11% as EHS 1. Similarly, their partner’s erection (means of 6.5 versus 3.7 24% of women reported their partners’ erections as times, respectively; Po0.0001). EHS3,14%asEHS2and10%asEHS1.Thereported A significantly greater percentage of men report- ability to maintain a fully hard and rigid penis during ing EHS 4 reported their overall health status as sexual activity declined rapidly with age, whether very good or excellent, compared with men having assessed by men or women (Supplementary Figure 1). EHS 3 erections (41% versus 28%, respectively; Men who reported EHS 4 were more likely to P ¼ 0.0094). report being very or completely satisfied with their ability to get an erection and to maintain an erection Interest in improving the sexual experience Respondents were asked to rate their interest in improving their sexual experience (Supplementary Figure 2). The percentage who reported very high, high or moderate interest in improving their sexual experience was significantly different between sexes (57% of men versus 47% of women; Po0.0011). Small proportions of men and women reported use of traditional, herbal and natural remedies in the past 4 weeks (13% and 12%, respectively); 24% of men and 23% of women reported being completely or very satisfied with these treatments. A smaller

Figure 3 Relationship of satisfaction with erection hardness Figure 4 Relationship between satisfaction with ability to get an and satisfaction with life priorities in men (a) and women QJ;(b). erection and to maintain an erection during intercourse and Participants were asked, ‘How satisfied are you with each aspect Erection Hardness Score (EHS). Participants were asked to rate of your life?’ and ‘How satisfied are you with the hardness of your how important both aspects were to them for a good sexual (for women, your partner’s) erection?’ Men and women who were experience. Participants also were asked, ‘If you had to generalize very/completely satisfied with erection hardness (n ¼ 840 and across your life today, how satisfied are you with the following 635, respectively) and those who were somewhat/not at all aspects of your performance?’ Data were obtained from all men, satisfied (n ¼ 379 and 425, respectively) were the basis for the including those who reported EHS 1 (n ¼ 99), EHS 2 (n ¼ 125), percentages shown. EHS 3 (n ¼ 522) and EHS 4 (n ¼ 1270).

International Journal of Impotence Research Asia-Pacific sexual health survey R King et al 140 proportion (9% of men and 8% of women) reported A sub-analysis of the GBSS considered data from use of western-style prescription medication in the only Asian countries.18 In the Asian GBSS, feeling same time period; 40% of men reported being attracted to one’s partner was somewhat or very completely or very satisfied with these treatments important for more than 90% of men and women, compared with only 7% of women (P ¼ 0.0014). respectively; however, only 39% of women in our For men, more respondents reported being comple- study ranked feeling attracted to their partner as tely or very satisfied with erection hardness when absolutely essential or very important. In contrast to using western-style prescription medications our study, where more than 50% of respondents than traditional/natural remedies (49% versus were not very satisfied with sex, 36% of men and 28%, respectively; P ¼ 0.0416); for women, satisfac- 38% of women in the Asian GBSS reported that they tion rates were more similar (21% versus 28%; were neutral or dissatisfied with their sex lives. The P ¼ 0.4362). percentage of respondents reporting that they were completely or very satisfied with erection hardness was somewhat higher in our study (26% for women and 38% for men) than in the Asian GBSS; only Discussion 23% of men and 15% of women in that study reported being very satisfied with erection hardness. In our survey of the Asia-Pacific region, more than Again, however, satisfaction with erection hardness half of all respondents reported being less than very was similarly correlated with sexual satisfaction satisfied with sex. Satisfaction with sex was linked and overall health in both studies. A similar to reported satisfaction with other life priorities. percentage of men and women from both studies Satisfaction with erection hardness, specifically, reported at least moderate interest in improving the was linked to satisfaction with specific aspects of sexual experience (Asian GBSS, 62% of men and the sexual experience and to overall life priorities. 39% of women; our study, 57% of men and 47% of Erection hardness was associated with importance women). of and satisfaction with erection-related elements Other studies have examined sexual satisfaction of men’s sexual performance. in the regions covered by this study. Self-reported Recent studies, both retrospective and prospec- sexual satisfaction in men did not differ substan- tive, have correlated erection hardness with tially between Japanese and American men aged 40 a positive sexual experience, using the validated to 79 years in community-based surveys, despite EHS measure employed in our study.15,16 However, Japanese men reporting more ED and less sexual these studies have mainly focused on men with drive.11 However, it was noted that discrepancies in defined ED.17 Our study is unique, because the linguistic equivalency of the questionnaires, it examined the general populations in the in addition to valid cultural beliefs, may have Asia-Pacific region, including Australia and New contributed to differences.11 Frequency of sex and Zealand, rather than restricting the study sample to sexual satisfaction were positively correlated in both those reporting ED. husbands and wives in Chinese couples from Hong The results from our study are similar to those Kong,12 although the specific contribution of erec- obtained from the Global Better Sex Survey (GBSS), tion hardness was not examined as was the case in which included Asian populations, as well as this study. In both of these studies, age-related populations from five other geographic regions in declines in sexual performance (erection function11 the sample population.3 More than half of all and sexual frequency12) were noted in men, paral- respondents in the GBSS and in our study were leling the age-related decline in erection hardness not fully or very satisfied with their sex life. observed in this study. Interestingly, our data showed that women in the Our study has limitations. The survey used Asia-Pacific region ranked sex as a lower priority multiple methods of assessment and participant and generally placed less importance on the sexual responses could have varied by the interview experience than men in the Asia-Pacific region. method (face-to-face interview versus Internet Although women in the GBSS also placed less survey). Further, the convenience sampling used importance on aspects of the sexual experience than for street intercept interviews in participating men, the gap between sexes was much smaller.3 The regions may not have yielded random samples, percentage of respondents reporting that they were because only subjects willing to discuss their sexual completely or very satisfied with erection hardness lives participated, or because of bias introduced by in our study (26% for women and 38% for men) was those performing the interviews. Although e-mail similar to the percentage of respondents reporting invitations for the Internet surveys were sent that they were very satisfied with erection hardness randomly, self-selection for response may have in the GBSS (36% of women and 38% of men). biased outcomes. Additionally, because face-to-face Additionally, satisfaction with erection hardness interviews were conducted only in large cities, was similarly associated with sexual satisfaction whereas the remainder of responses required using and overall health in both studies. the Internet, the study sample likely reflects an

International Journal of Impotence Research Asia-Pacific sexual health survey R King et al 141 urban, educated population. The rural population 5 Althof SE, Eid JF, Talley DR, Brock GB, Dunn ME, Tomlin ME may hold differing views on sexuality. et al. Through the eyes of women: the partners’ perspective on In conclusion, most of the Asia-Pacific population tadalafil. Urology 2006; 68: 631–635. 6 Edwards D, Hackett G, Collins O, Curram J. Vardenafil (including Australia and New Zealand) reported improves sexual function and treatment satisfaction in being less than satisfied with sex and X47% of men couples affected by erectile dysfunction (ED): a randomized, and women indicated interest in improving the double-blind, placebo-controlled trial in PDE5 inhibitor-naive sexual experience. Satisfaction with sex was asso- men with ED and their partners. J Sex Med 2006; 3: 1028–1036. ciated with satisfaction with life priorities. Erection 7 Fisher WA, Rosen RC, Eardley I, Sand M, Goldstein I. Sexual hardness was associated with sexual satisfaction experience of female partners of men with erectile dysfunc- and activity, satisfaction with life priorities and tion: the female experience of men’s attitudes to life overall health; men with suboptimal erections were events and sexuality (FEMALES) study. J Sex Med 2005; 2: less satisfied with these elements. 675–684. 8 Goldstein I, Fisher WA, Sand M, Rosen RC, Mollen M, Brock G et al. Women’s sexual function improves when partners are administered vardenafil for erectile dysfunction: a prospec- Conflict of interest tive, randomized, double-blind, placebo-controlled trial. J Sex Med 2005; 2: 819–832. 9 Heiman JR, Talley DR, Bailen JL, Oskin TA, Rosenberg SJ, Dr King has acted as a consultant, researcher and Pace CR et al. Sexual function and satisfaction in heterosexual speaker for Pfizer Inc. Dr Shah has received con- couples when men are administered sildenafil citrate (Viagra) sultancy fees from Pfizer Inc. Drs Marumo, Paick, for erectile dysfunction: a multicentre, randomised, Zhang, Pangkahila, Yip, Jiann have no conflicts to double-blind, placebo-controlled trial. Br J Obstet Gynaecol 2007; 114: 43–47. report. Dr Ong is an employee of Pfizer Inc. 10 Nicolosi A, Glasser DB, Kim SC, Marumo K, Laumann EO. Sexual behaviour and dysfunction and help-seeking patterns in adults aged 40-80 years in the urban population of Asian countries. BJU Int 2005; 95: 609–614. Acknowledgments 11 Masumori N, Tsukamoto T, Kumamoto Y, Panser LA, Rhodes T, Girman CJ et al. Decline of sexual function with This study was funded by Pfizer Inc. Editorial age in Japanese men compared with American men–results of assistance was provided by Tiffany Brake, PhD, at two community-based studies. Urology 1999; 54: 335–344; Complete Healthcare Communications and was discussion 344–345. 12 Cheung MW, Wong PW, Liu KY, Yip PS, Fan SY, Lam TH. funded by Pfizer Inc, New York, NY, USA. Clinical- A study of sexual satisfaction and frequency of sex among Trials.gov Identifier: None. Hong Kong Chinese couples. J Sex Res 2008; 45: 129–139. 13 Ying Ho PS. Not so great expectations: sex and housewives in Hong Kong. J Sex Res 2008; 45: 338–349. 14 Francoeur RT, Noonan RJ (eds). The Continuum Complete References International Encyclopedia of Sexuality. The Continuum International Publishing Group Inc.: New York, 2004. 1 Nicolosi A, Laumann EO, Glasser DB, Moreira Jr ED, Paik A, 15 Mulhall JP, Goldstein I, Bushmakin AG, Cappelleri JC, Gingell C. Sexual behavior and sexual dysfunctions after age Hvidsten K. Validation of the Erection Hardness Score 40: the global study of sexual attitudes and behaviors. Urology (EHS). J Sex Med 2007; 4: 1626–1634. 2004; 64: 991–997. 16 Cappelleri JC, Stecher VJ. An assessment of patient-reported 2 Goldstein I, Mulhall JP, Bushmakin AG, Cappelleri JC, outcomes for men with erectile dysfunction: Pfizer’s perspec- Hvidsten K, Symonds T. The Erection Hardness Score and tive. Int J Impot Res 2008; 20: 343–357. its relationship to successful sexual intercourse. J Sex Med 17 Montorsi F, Padma-Nathan H, Glina S. Erectile function and 2008; 5: 2374–2380. assessments of erection hardness correlate positively with 3 Mulhall J, King R, Glina S, Hvidsten K. Importance of and measures of emotional well-being, sexual satisfaction, satisfaction with sex among men and women worldwide: and treatment satisfaction in men with erectile dysfunction results of the Global Better Sex Survey. J Sex Med 2008; 5: treated with sildenafil citrate (Viagra). Urology 2006; 68: 788–795. 26–37. 4 Mulhall JP, Althof SE, Brock GB, Goldstein I, Ju¨ nemann K-P, 18 Tan HM, Marumo K, Yang DY, Hwang TI, Ong M. The Kirby M. Erectile dysfunction: monitoring response to treat- importance of and satisfaction with sex among Asian men and ment in clinical practice—recommendations of an inter- women: the global better sex survey in Asia. Int J Urol 2009; national consensus panel. J Sex Med 2007; 4: 448–464. 16: 507–514.

Supplementary Information accompanies the paper on International Journal of Impotence Research website (http://www.nature.com/ijir)

International Journal of Impotence Research