Kia Fatt Quek, PhD,* Atiya Abdul Sallam, MBBS, MPH, MSc, Chai Heng Ng, BScHons, and Chong Beng Chua, MD, FRCS (Urol)

Transcription

1 Blackwell Publishing IncMalden, USAJSMJournal of Sexual Medicine International Society for Sexual Medicine Original ArticlesSexual Problems among Men in MalaysiaQuek et al. 70 Prevalence of Sexual Problems and Its Association with Social, Psychological and Physical Factors among Men in a Malaysian Population: A Cross-Sectional Study Kia Fatt Quek, PhD,* Atiya Abdul Sallam, MBBS, MPH, MSc, Chai Heng Ng, BScHons, and Chong Beng Chua, MD, FRCS (Urol) *School of Medicine and Health Sciences, Monash University Malaysia, Petaling Jaya, Selangor Darul Ehsan, Malaysia; Department of Social and Preventive Medicine, University of Malaya, Kuala Lumpur, Malaysia; Department of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Sunway Medical Centre, Bandar Sunway, Petaling Jaya, Selangor Darul Ehsan, Malaysia DOI: /j x ABSTRACT Introduction. Sexual problems are common in the general population. Studies have shown that most of these sexual problems are related to their social lives, medical illnesses, and psychological status. Among the sexual problems in men, premature ejaculation (PE) is one of the most frequent, yet it is the least well-understood of the sexual dysfunctions of men. Aim. To determine the prevalence of sexual problem particularly PE and erectile dysfunction (ED) among people living in urban areas and to investigate the characteristics associated with these sexual problems in a Malaysian population. Main Outcome Measure. The PE which is defined as an intravaginal ejaculation latency time less than 2 minutes was assessed in the ED and non-ed group. Methods. The Hospital Anxiety and Depression scale is used as a measure of the psychological status [30]. The ED status was assessed using the International Index of Erectile Function questionnaire. Results. The prevalence of self-reported sexual problems for ED and PE were 41.6% and 22.3%, respectively. In those subjects with ED, 33.5% reported to have PE. Of the total of 430 subjects, anxiety was present in 8.1%, while depression was 5.3%. The prevalence of PE accounted for 25% anxiety and 14.6% for depression respectively in the population. EDs were associated with diabetes and hypertension (OR [95% CI]: 5.33 [2.33, 10.16], 3.40 [1.76, 6.57], P < 0.05), respectively, while factors associated with PE were anxiety and depression (OR [95% CI]: 1.29 [0.68, 2.45], 1.39 [0.69, 2.78]), respectively. Conclusion. Prevalence of ED is associated with medical symptoms such as diabetes and hypertension and a rise in the prevalence of age while psychological distress such as anxiety and depression also contribute to a higher PE rate. Quek KF, Sallam AA, Ng CH, and Chua CB. Prevalence of sexual problems and its association with social, psychological and physical factors among men in a Malaysian Population: A cross-sectional study. J Sex Med 2008;5: Key Words. PE; ED; Type 2 Diabetes; Hypertension; HADS; IIEF-5 Introduction S exual problem is a common medical disorder among the general population [1 15]. Studies have shown that most of these sexual problems are related to their social lives, medical illnesses, and psychological status. The areas of social life which relates to sexual problem are marriage status and its relationships [16], while medical illnesses are due to diabetes [17] and hypertension [18]. Anxiety [19,20] and depression [21] are among the psychological problems implicated to sexual problem, although the cause and effect natures of this link remains unknown International Society for Sexual Medicine

2 Sexual Problems among Men in Malaysia 71 Among the sexual problems in men, premature ejaculation (PE) is one of the most frequently encountered sexual dysfunctions [22] with possible familial genetic vulnerability [23]. Unlike erectile dysfunction (ED), in which vaginal penetration is impossible without an erection [24], men with PE are in fact functional and able to have an orgasm. PE is defined as a persistent or recurrent ejaculation with minimal stimulation before, on, or shortly after penetration, and before the person wishes it, due to little or no voluntary control, which causes distress to the sufferer and/or partner [25]. Premature ejaculation is a prevalent condition that can cause distress for a man, his partner, and their relationship. This may also be the early symptom of ED because of the rising anxiety and frustration due to soft erection [26]. In the clinical setting, PE is defined as ejaculation after a fixed time (range from 0.5 minute to 7 minutes, depending on clinical setting) after penetration or is referred to as intravaginal ejaculation latency time (IELT) [27,28,29]. It is postulated that PE may be part of the normal biological variation of the IELT in men, but its paradoxical or fixed course throughout life (chronic PE) is considered as being pathological [26]. The lack of information as to what constitutes sexual problem has made it impossible to establish the etiology, diagnostic methods, and management of this condition. Thus, the aim of the present study is to determine the prevalence of sexual problem particularly PE and ED among people living in urban areas and to investigate the characteristics associated with these sexual problems in a Malaysian population. Materials and Methods A total of 430 subjects were recruited in the study, after giving them a detailed information sheet on the study procedures. Subjects who consented to take part in the study were given and asked to complete a multiple-choice questionnaire. The questionnaire consisted of five parts, namely (i) demographic data, e.g., age, marital status, education, occupation, etc.; (ii) medical history; (iii) sexual function status that enquire about sexual behavior, sexual difficulties, and satisfaction. The PE is defined as an IELT 2 minutes; and (iv) operationalization of PE using the length of time between penetration and ejaculation. The Hospital Anxiety and Depression Scale (HADS) is used as a measure of psychological status [30]. The scores for anxiety and depression were calculated out of a maximum score of 21 for each of the scales. A score of 11 or more on either of the scales was considered indicative of the presence of anxiety or depression [30]. The ED status was assessed using the International Index of Erectile Function (IIEF-5) questionnaire, of which a threshold scores of <21 to diagnosis ED. Data Analysis The data collected were processed and analyzed by using routine statistical methods, and a P < 0.05 level was taken to indicate the significant difference. Measures of association were summarized by the prevalence odds ratio with 95% confidence intervals. All the statistics was performed by using the SPSS version 11.0 (SPSS Inc., Chicago, IL, USA). Results A total of 430 subjects consented to participate in the study. Demographic characteristics of the subjects are shown in Table 1. The prevalence of selfreported sexual problem for ED and PE were 41.6% and 22.3%, respectively. In those subjects with ED, there was 33.5% reported concurrently to have PE. The prevalence rates in different age groups are shown in Table 2. The present results show the overall prevalence rate of sexual problems increasing with age particularly in ED. In contrast, PE rate decreased with age. Data on the IIEF-5 score of ED among subjects with ED are presented in Figure 1. The result shows that the majority of subjects reported to have ED have mild to moderate severity of ED. From the HAD scale, the median anxiety score and depression score were 6 and 4, respectively. Of the total 430 subjects, anxiety was present in 8.1%, while depression was 5.3%. The prevalence of PE accounted for 25% and 14.6% respectively for anxiety and depression in this population. This was related to the severity of both anxiety and depression by HAD scale, with statistically significant trend across categories of HADS score (Figures 2 and 3). Erectile dysfunctions were associated with a variety of predominant medical illnesses. The main association was with self-reported type 2 diabetes (Table 3). When adjusted for age, the odds ratio for this association was 5.33 (95% CI 2.33, 10.16). EDs were also associated with selfreported hypertension with an adjusted odds ratio of 3.40 (95% CI 1.76, 6.57). Diabetes and hyper-

3 72 Quek et al. Table 1 Demographic of subjects with and without premature ejaculation (PE) by the presence of erectile dysfunction (ED) ED No ED Demographic characteristics PE (n = 60) No PE (n = 119) PE (n = 36) No PE (n = 215) Mean (SD) age (years) 50.4 ± ± 10.0* 34.5 ± ± 9.0 Ethnic origin Malay 25 (41.7) 38 (31.9) 20 (55.6) 97 (45.1) Chinese 12 (20.0) 54 (45.4) 8 (22.2) 88 (40.9) Indian 23 (38.3) 27 (22.7) 8 (22.2) 30 (14.0) Educational status No formal education. 4 (6.7) 10 (8.4) 1 (0.5) Primary education 4 (6.7) 15 (12.6) 6 (2.8) Secondary education 6 (10.0) 39 (32.8) 6 (16.7) 21 (9.8) High education 36 (60.0) 55 (46.2) 30 (83.3) 187 (87.0) Occupational status Employed 36 (60.0) 59 (49.6) 36 (100) 204 (94.9) Unemployed 4 (6.7) 7 (5.9) 3 (1.4) Retired 20 (33.3) 53 (44.5) 8 (3.7) Civil status Married 4 (6.7) 3 (2.5) 6 (16.7) 28 (13.0) Single 53 (88.3) 116 (97.5) 29 (80.5) 186 (86.5) Divorced 3 (5.0) 1 (2.8) 1 (0.5) No. of children Nil 6 (10.0) 6 (5.0)) 13 (36.1) 40 (18.6) (30.0) 39 (32.8) 10 (27.8) 69 (32.1) (45.0) 49 (41.2) 9 (25.0) 82 (38.1) >5 9 (15.0) 25 (21.0) 4 (11.1) 24 (11.2) Length of relationship (years) (15.0) 7 (5.9) 18 (50.0) 74 (34.4) (3.3) 7 (5.9) 6 (16.7) 62 (28.8) (28.3) 29 (24.4) 10 (27.8) 50 (23.3) >20 32 (53.3) 76 (63.9) 2 (5.5) 29 (13.5) Cigarettes (yes/no) 20/40 33/82 16/20 75/92 Alcoholic (yes/no) 12/48 21/98 3/33 14/171 Values are numbers (percentages); t-test result: *P < tension were also associated with other erectile problems such as problem of getting erection and the ability to maintain an erection. In addition, the main association with PE was anxiety and after adjusted for age, the odds ratio (95% CI) was 1.29 (0.68, 2.45) (Table 3). An association was also observed between PE and depression, with an odds ratio of 1.39 (0.69, 2.78). There is a significant association between nocturia and ED (Table 4) (P = 0.001). Those who have more frequency of sexual intercourse were found to significantly have high PE (Table 5) (P = 0.005). None of the cases are prostatitis and there are only few cases of hyperlipidemia/hypercholesterolemia. Those who had regular sexual and intercourse (2 3 times a week) are relatively low and in this study, all single subjects have partner. No significant difference between time of ejaculation and the marriage status was noted in this study (P = 0.112). Discussion The prevalence of ED in this study is almost similar to other study [32]. Similarly, the findings of PE in this study shared some similarity with other study as well [31]. This study looks at the prevalence of sexual problem especially PE and its rela- Table 2 The prevalence of sexual dysfunction according to age group Age group Sexual problem (n) Normal (n) PE ED PE and ED (17.0) 3 (6.0) 1 (2.0) (13.0) 9 (7.0) 14 (10.0) (9.0) 22 (23.0) 13 (14.0) (1.0) 53 (55.0) 19 (20.0) (0.0) 32 (63.0) 13 (25.0) 88.0 ED = erectile dysfunction; PE = premature ejaculation. Overall sexual problem (%)

4 Sexual Problems among Men in Malaysia 73 % of severity of ED IIEF-5 score category % Low score Medium score High score Depression level Figure 3 Percentage of men with premature ejaculation in each depression level. 0 mild mild to moderate moderate severe Degree of erectile dysfunction very severe Figure 1 Percentage of men with the various degree of ED (n = 179). ED = erectile dysfunction; IIEF-5 = International Index of Erectile Function. tion with a wide range of medical, social, and psychological factors in a general population sample. It is generally believed that male sexual interest and activity persist throughout their entire life. However, age was found to be an important association with sexual problems particularly ED. This may reflect its association with medical symptoms, which rises in prevalence of age such as diabetes and hypertension. In addition, marital dissatisfaction such as a lack or loss of sexual desire also accounted for the increased prevalence of ED. In contrast, the age of the men and their marital dissatisfaction were not correlated with the PE rate. Nonetheless, psychological distress such as anxiety and depression contributes mostly to a higher PE rate, which is in accord with previous findings [33]. % Anxiety/depression score > Figure 2 Percentage of men with premature ejaculation in each anxiety level (n = 96) Anxiety level 68.6 Low score Medium score High score Most of the comorbities are associated with ED and PE and the results are similar to other study [34,35]. The ED is found to be highly prevalent among the higher age group, whereas the PE is found higher in lower age group. Hyperlipidemia/ hypercholesterolemia were not found to be significantly associated with ED in this study because of low number of cases of hyperlipidemia/hypercholesterolemia noted in this study. Lower urinary tract symptoms usually have been noted to be associated with ED and in this study nocturia was statistically found associated with ED. Those who have more nocturia will be more likely to develop ED. All the single men (n = 40) has regular partner. Therefore, the reported ejaculation is for sexual intercourse. All ejaculation times were assessed on sexual intercourse and not masturbation and there is no attempt in the study to compare the difference for ejaculation time during sexual intercourse and masturbation. Various psychological treatments have been proposed to treat or cope with PE. As far as psychologists are concerned, PE is a psychological disorder caused by the learned behavior, hyperexcitability in the genital part or unconscious psychological conflicts. The use of psychotherapy is to help to delay ejaculation or to assist couples to learn to accept PE [36]. However, animal and human studies have shown that ejaculation is regulated by various areas in the central nervous system, and the rapidity of ejaculation is controlled by neurotransmitter such as serotonin [37]. Presently, a number of clinical studies on serotonin reuptake inhibitors (e.g., paroxetine, clomipramine, and sertaline) have repeatedly shown the efficacy of serotonergic antidepressants in delaying ejaculations [37 39].

5 74 Quek et al. Table 3 Adjusted odds ratio (95% CI) for association between various self-reported social, medical, and psychological factors and various sexual problems Sexual problem Age (years) Marital difficulties Diabetes Hypertension Anxiety Depression Erectile problem Problem getting an erection 1.13 (1.10, 1.16) 1.45 (0.58, 3.61) 8.01 (6.59, 9.14) 3.88 (1.97, 7.63) 1.38 (0.72, 2.64) 1.62 (0.79, 3.30) Problem maintaining an erection 1.08 (1.06, 1.11) 2.24 (0.81, 6.17) 3.89 (1.85, 8.18) 2.36 (1.17, 4.74) 1.29 (0.62, 2.70) 1.27 (0.56, 2.79) Erectile dysfunction 1.13 (1.11, 1.16) 1.49 (0.57, 3.86) 5.33 (2.33, 10.16) 3.40 (1.76, 6.57) 1.29 (0.68, 2.45) 1.39 (0.69, 2.78) Premature ejaculation 1.06 (0.98, 1.02) 0.86 (0.36, 2.03) 0.33 (0.16, 0.67) 1.42 (0.71, 2.86) 2.83 (1.45, 5.54) 2.08 (0.97, 4.44) Table 4 Nocturia urination Association between nocturia and ED Non-ED This study has a few limitations such as a selfreporting methodology and, a survey confined to a particular urban area as part of a cross-sectional survey. However, we do not recommend face-toface interviews because this may give rise to embarrassment when talking about very private and sensitive issues, or may induce subjects to give socially desirable answers about their sexual behavior. In the present study, we have explained the objective of the study and participants have to give their consent before commencement of these self-reported surveys. Even though the prevalence of sexual problems may be higher in those who have consented to participate in such a survey that it in turn may lead to an overestimation of their occurrence in the general population, this should not affect the integrity of the observed association. In addition, we used an in-house developed questionnaire which essentially has good sensitivity and specificity, and thus is a suitable, reliable, valid, and sensitive instrument to measure the sexual dysfunction in the general population. Although IELT has been occasionally used as the determination of PE, nevertheless, it is made known that IELT alone may not sufficient or reliable to be used as PE determination. The findings would be more comprehensive if other instruments such as Index of Premature Ejaculation could be utilized [40]. This study is unable to show whether there are any cultural or social differences that can arise between this study compared with other studies. From the findings of this study, we have shown that sexual dysfunction is prevalent in the male population, and several physiological and physical factors appear to be associated with these prob- Table 5 Relationship between frequency of sexual intercourse in a month and PE Cases n Mean SD SEM Non-PE PE t-test, P = PE = premature ejaculation. ED Total Not frequent 249 (60.29) 164 (39.71) 413 (100.00) Frequent 2 (11.76) 15 (88.24) 17 (100.00) 251 (58.37) 179 (41.63) 430 (100.00) χ 2, P = ED = erectile dysfunction.

6 Sexual Problems among Men in Malaysia 75 lems. Further work clarifying the direction of the association is needed to address the impact of both physical and psychological factors which play a part in the etiology of sexual problems. A similar approach should also be extended to their counterpart (female) as previous studies have shown arousal problem, orgasmic dysfunction, inhibited enjoyment, vaginal dryness, and dyspareunia were among the major sexual problems encountered by females [33]. The pattern of these sexual problems in females in association with other characteristics should be addressed promptly so that they can complement both genders to cope with their sexual problem effectively. Currently, there is a wide range of physical and physiological approaches for the treatment of sexual problems described in literature [41]. Our study raises the possibility that if such approaches are effective, they may have a wide range of social and psychological benefits in the general population. Acknowledgment We would like to express our gratitude and sincere thanks to the Research and Development Unit, University of Malaya for providing the research grant (FP010/ 2003C) for this study. Corresponding Author: Quek Fatt, PhD, School of Medicine and Health Sciences, Monash University Malaysia, No. 20 & 22, Jalan PJS 11/5, Bandar Sunway, Petaling Jaya, Selangor Darul Ehsan, Malaysia. Tel: (+603) ext. 333; Fax: (+603) ; Quek.Kia.Fatt@med.monash.edu.my Conflict of Interest: None declared. References 1 Lewis RW, Fugl-Meyer KS, Bosch R, Fugl-Meyer AR, Laumann EO, Lizza E, Martin-Morales A. Epidemiology/risk factors of sexual dysfunction. J Sex Med 2004;1: Basile Fasolo C, Mirone V, Gentile V, Parazzini F, Ricci E; Andrology Prevention Week centers; Italian Society of Andrology (SIA). Premature ejaculation: Prevalence and associated conditions in a sample of 12,558 men attending the andrology prevention week 2001-a study of the Italian Society of Andrology (SIA). J Sex Med 2005;2: Moreira ED Jr, Kim SC, Glasser D, Gingell C. Sexual activity, prevalence of sexual problems, and associated help-seeking patterns in men and women aged years in Korea: Data from the Global Study of Sexual Attitudes and Behaviors (GSSAB). J Sex Med 2006;3: Patrick DL, Althof SE, Pryor JL, Rosen R, Rowland DL, Ho KF, McNulty P, Rothman M, Jamieson C. Premature ejaculation: An observational study of men and their partners. J Sex Med 2005;2: Richardson D, Goldmeier D. Premature ejaculation Does country of origin tell us anything about etiology? J Sex Med 2005;2: Waldinger MD, Zwinderman AH, Olivier B, Schweitzer DH. Proposal for a definition of lifelong premature ejaculation based on epidemiological stopwatch data. J Sex Med 2005;2: Sotomayor M. The burden of premature ejaculation: The patient s perspective. J Sex Med 2005;2(2 suppl): Rowland D, van Diest S, Incrocci L, Slob AK. Psychosexual factors that differentiate men with inhibited ejaculation from men with no dysfunction or another sexual dysfunction. J Sex Med 2005;2: Richardson D, Wood K, Goldmeier D. A qualitative pilot study of islamic men with lifelong premature (rapid) ejaculation. J Sex Med 2006;3: Rowland D, Perelman M, Althof S, Barada J, McCullough A, Bull S, Jamieson C, Ho KF. Selfreported premature ejaculation and aspects of sexual functioning and satisfaction. J Sex Med 2004;1: McMahon CG, Abdo C, Incrocci L, Perelman M, Rowland D, Waldinger M, Xin ZC. Disorders of orgasm and ejaculation in men. J Sex Med 2004;1: El-Sakka AI, Hassoba HM, Sayed HM, Tayeb KA. Pattern of endocrinal changes in patients with sexual dysfunction. J Sex Med 2005;2: Perelman M, Shabsigh R, Seftel A, Althof S, Lockhart D. Attitudes of men with erectile dysfunction: A cross-national survey. J Sex Med 2005;2: Saenz de Tejada I, Angulo J, Cellek S, Gonzalez- Cadavid N, Heaton J, Pickard R, Simonsen U. Pathophysiology of erectile dysfunction. J Sex Med 2005;2: Lewin J, King M. Sexual medicine. Towards an integrated discipline. BMJ 1997;314: Rust J, Golombok S, Collier J. Marital problems and sexual dysfunction: How are they related? Br J Psychiatry 1988;152: Hackett GI. Impotence- the most neglected complication of diabetes. Diabetes Res 1995;28: Weiss RJ. Effects of antihypertensive agents on sexual function. Am Fam Physician 1991;44: Ernst C, Foldenyi M, Angst J. The Zurich Study: XXI. Sexual dysfunctions and disturbances in young adults. Data of a longitudinal epidemiological study. Eur Arch Psychiatry Clin Neurosci 1993;243: Norton GR, Jehu D. The role of anxiety in sexual dysfunctions: A review. Arch Sex Behav 1984;13:

7 76 Quek et al. 21 Petrie WM. Sexual effects of antidepressants and psychomotor stimulant drugs. Mod Probl Pharmacopsychiatry 1980;15: Seftel AD, Althof SE. Rapid ejaculation. Curr Urol Rep 2000;1: Waldinger MD, Rietschel M, Nothen MM, Hengeveld MW, Olivier B. Familial occurrence of primary premature ejaculation. Psychiatr Genet 1998;8: National Institute of Health Consensus Development Panel on Impotence. Impotence. JAMA 1993;270: Rowland DL, Cooper SE, Schneider M. Defining premature ejaculation for experimental and clinical investigations. Arch Sex Behav 2001;30: Waldinger MD. The neurobiological approach to premature ejaculation. J Urol 2002;168: Waldinger MD, Hengeveld MW, Zwinderman AH. Paroxetine treatment of premature ejaculation: A double-blind, randomized, placebo-controlled study. Am J Psychiatry 1994;151: Waldinger MD, Hengeveld MW, Zwinderman AH, Olivier B. Effect of SSRI antidepressants on ejaculation: A double-blind, randomized, placebocontrolled study with fluvoxamine, paroetine and sertraline. J Clin Psychopharmacol 1998;18: Waldinger MD, Quinn P, Dilleen M, Mundayat R, Schweitzer DH, Boolell M. A multinational population survey of intravaginal ejaculation latency time. J Sex Med 2005;2: Zigmond AS, Snaith RP. The Hospital Anxiety and Depression scale. Acta Psychiatr Scand 1983;67: Montorsi F. Prevalence of premature ejaculation: A global and regional perspective. J Sex Med 2005; 2: Grenier G, Byers S. Operationalizing early or premature ejaculation. J Sex Res 2001;38: Dunn KM, Croft PR, Hackett GI. Association of sexual problems with social, psychological, and physical problems in men and women: A cross sectional population survey. J Epidemiol Community Health 1999;53: Johannes JB, Araujo AB, Feldman HA, Derby CA, Kleinman KP, McKinlay JB. Incidence of erectile dysfunction in men years old: Longitudinal results from the Massachusetts male aging study. J Urol 2000;163: Derby CA, Araujo AB, Johannes JB, Feldman HA, McKinlay JB. Measurement of erectile dysfunction in population-based studies: The use of a single question self-assessment in the Massachusetts Male Aging Study. Int J Impot Res 2000; 12: Metz ME, Pryor JL, Nesvacil LJ, Abuzzahab F, Koznar J. Premature ejaculation: A psychophysiological review. J Sex Marital Ther 1997;23: Waldinger MD, Zwinderman AH, Schweitzer DH, Olivier B. Relevance of methodological design for the interpretation of efficacy of drug treatment of premature ejaculation: A systematic review and meta-analysis. Int J Impot Res 2004; 16: Waldinger MD, Berendsen HHG, Blok BFM, Olivier B, Holstege G. Premature ejaculation and SSRIinduced delayed ejaculation: The involvement of the serotonergic system,. Behav Brain Res 1998; 92: Waldinger MD, Schweitzer DH, Olivier B. Ondemand SSRI treatment of premature ejaculation: Pharmacodynamic limitations for relevant ejaculation delay and consequent solutions. J Sex Med 2005;2: Review. 40 Althof S, Rosen R, Symonds T, Mundayat R, May K, Abraham L. Development and validation of a new questionnaire to assess sexual satisfaction, control, and distress associated with premature ejaculation. J Sex Med 2006;3: Lue TF, Giuliano F, Montorsi F, Rosen RC, Andersson KE, Althof S, Christ G, Hatzichristou D, Hirsch M, Kimoto Y, Lewis R, McKenna K, Mac- Mahon C, Morales A, Mulcahy J, Padma-Nathan H, Pryor J, de Tejada IS, Shabsigh R, Wagner G. Summary of the recommendations on sexual dysfunctions in men. J Sex Med 2004;1:6 23.