Sexual Dysfunction. Jae Il Kang, Byeong Kuk Ham, Mi Mi Oh, Je Jong Kim, Du Geon Moon. DOI: /kju

Similar documents
Assessment of Erectile and Ejaculatory Function after Penile Prosthesis Implantation

Serum Total Testosterone Level and Identification of Late-Onset Hypogonadism: A Community-Based Study

ISSN: (print), (electronic)

PRISM Bruges June Herman Leliefeld Urologist. The Netherlands

The clinical importance of testosterone in men with type 2 diabetes

R. Charles Welliver, Jr.,* Herbert J. Wiser, Robert E. Brannigan, Kendall Feia, Manoj Monga and Tobias S. K ohler

Sponsored by. Schering. Sidney Glina

THE RELEVANCE OF TESTOSTERONE THERAPY IN MANAGING PATIENTS WITH ERECTILE DYSFUNCTION

Progression of Peyronie s Disease during Tamoxifen Treatment

ORIGINAL ARTICLE Post-marketing surveillance study of the efficacy and safety of vardenafil among patients with erectile dysfunction in primary care

Male Menopause: Disease or Pseudoscience? March 4, 2015 story: FDA to require warning on labels of testosterone products.

Administration of Testosterone and its Rationale in the Treatment of Erectile Dysfunction

Update on diagnosis and complications of adult and elderly male hypogonadism

Point-Counterpoint: Late Onset Hypogonadism (LOH)

Hypogonadal symptoms in young men are associated with a serum total testosterone threshold of 400 ng/dl

Managing Testosterone Deficiency: A Practical Guide. John Grantmyre MD Professor of Urology Dalhousie University

Testosterone and PDE5 inhibitors in the aging male

Testosterone Deficiency with Erectile Dysfunction in Mongolian Men

The use of the simplified International Index of Erectile Function (IIEF-5) as a diagnostic tool to study the prevalence of erectile dysfunction

Androgen deficiency in men has attracted much

Keywords: Position statement, expert opinion, hypogonadism, men, testosterone, calculated bioavailable testosterone

Testosterone levels in men with erectile dysfunction

testosterone and LH concentrations in the morning ( hours) and evening ( hours).

/04/ /0 Reprinted from Vol. 172, , August 2004 THE JOURNAL OF UROLOGY

Men Getting Older Will Testosterone Keep Him Young?

Erectile Dysfunction: A Primer for Primary Care Providers

The Journal of International Medical Research 2012; 40:

/03/ /0 Vol. 170, , July 2003 THE JOURNAL OF UROLOGY. Printed in U.S.A. Copyright 2003 by AMERICAN UROLOGICAL ASSOCIATION

Prevalence of Sarcopenia Adjusted Body Mass Index in the Korean Woman Based on the Korean National Health and Nutritional Examination Surveys

Prevalence of hypogonadism in males aged at least 45 years: the HIM study

Androgen Pattern and Erectile Function in Newly Diagnosed Type 2 Diabetes

Sexual dysfunction in men with diabetes

Androgens and male aging: current evidence of safety and efficacy

6/14/2010. GnRH=Gonadotropin-Releasing Hormone.

Andropause state of the art 2015 and review of selected aspects

BIOCHEMICAL TESTS FOR THE INVESTIGATION OF COMMON ENDOCRINE PROBLEMS IN THE MALE

Gonadal Hormones and Gonadotrophins in healthy males beyond forty years Abdul Jalil Ansari 1, SAM Golam Kibria 2, Fakhrul Islam 3

Efficacy and Safety of Linear Focused Shockwaves for Erectile Dysfunction (RENOVA) A Second Generation Technology

Index. urologic.theclinics.com. Note: Page numbers of article titles are in boldface type.

Hormone Replacement Therapy

Hypogonadism 4/27/2018. Male Hypogonadism -- Definition. Epidemiology. Objectives HYPOGONADISM. Men with Hypogonadism. 95% untreated.

A dro r gen e R e R p e lac a e c m e e m n e t t T her e a r p a y Androgen Replacement Therapy in the Aging O j b ecti t ve v s Male

Testosterone Replacement Alone for Testosterone Deficiency Syndrome Improves Moderate Lower Urinary Tract Symptoms: One Year Follow-Up

Are dehydroepiandrosterone sulphate and lipids associated with erectile dysfunction?

The reality of LOH-symptoms

Sexual Function in Male Patients with Metabolic Syndrome and Effective Parameters on Erectile Dysfunction

administered before treatment and during follow-up.

ORIGINAL ARTICLE The quantitative ADAM questionnaire: a new tool in quantifying the severity of hypogonadism

Diagnosis and management of sexual dysfunction. Dr Chris Simpson Consultant Psychiatrist

Initial experience with linear focused shockwave treatment for erectile dysfunction: a 6-month follow-up pilot study

The Clinical relevance of serum testosterone and sexual activity in the ageing male

How to treat: TRT modalities and formulations

ORIGINAL ARTICLE Hypogonadism is associated with overt depression symptoms in men with erectile dysfunction

Erectile dysfunction

An Evidence-based Review of Clinical Trial Data

Diagnosis and Clinical Evaluation of Hypogonadism in Adult Patients with Obesity and Diabetes

Testosterone therapy in erectile dysfunction

An Update on Men s Health and Sexual Function

Validation and Reliability of a Thai Version of the International Index of Erectile Dysfunction (IIEF) for Thai Population

Importance of abdominal circumference and body mass index values in predicting male hypogonadism A practical approach

A Study of relationship between frailty and physical performance in elderly women

Circulating sex steroid hormone concentrations

The Role of Testosterone in the Sexual Function. Luiz Otavio Torres President Elect of ISSM Belo Horizonte - Brazil

International Index of Erectile Function Questionnaire IIEF

TRT and localized protate cancer

ENVIRONMENTAL HEALTH PERSPECTIVES

Corporate Medical Policy

depression, anxiety, testosterone and luteinizing hormone levels in disorders of sexual function

Review Article: Practical Aspects of Testosterone Deficiency Syndrome in Clinical Urology

The association of time of day and serum testosterone concentration in a large screening population

ERECTILE DYSFUNCTION DIAGNOSIS

Measurement of erectile dysfunction in population-based studies: the use of a single question self-assessment in the Massachusetts Male Aging Study

Diagnosis and Treatment of Sexual Dysfunctions in Late-Onset Hypogonadism

ORIGINAL ARTICLE Efficacy of testosterone gel in the treatment of erectile dysfunction in hypogonadal hemodialysis patients: a pilot study

GUIDELINES ON ERECTILE DYSFUNCTION

Alternative management of hypogonadism Tamoxifen. Emmanuele A. Jannini, MD Tor Vergata University of Rome ITALY

Epidemiology/Risk Factors of Sexual Dysfunction

Hypogonadism in Men. CME Away India & Sri Lanka March 23 - April 7, 2018

ScienceDirect. Ioan Scarneciu a,b *, Sorin Lupu a,c, Camelia C. Scarneciu b,d PSIWORLD Available online at

Erectile function and late-onset hypogonadism symptoms related to lower urinary tract symptom severity in elderly men

I N T I M A C Y A N D S E X U A L I T Y I N L A T E R L I F E

IC351 (tadalafil, Cialis): update on clinical experience

Ian Eardley Department of Urology, Leeds Teaching Hospital Trust

Severe erectile dysfunction is a marker for hyperprolactinemia

BIOAVAILABLE testosterone levels in men decrease by

EFFICACY AND SAFETY OF TESTOSTERONE THERAPY FOR LATE-ONSET HYPOGONADISM: AN UPDATE

HYPOGONADISM DEFINITION: PRODUCTION OF SEX HORMONES AND GERM CELLS IS INADEQUATE (ENDOCRINE SOCIETY)

Comparison of different methods for the measurement of serum testosterone in the aging male

Penile Implant Should be Offered Early

Late-onset hypogonadism or ADAM: diagnosis

Endocrine Update Mary T. Korytkowski MD Division of Endocrinology University of Pittsburgh

An Idea Whose Time Has Come-Male Health Programs: An Opportunity For Clinical Expansion and Better Health

Chapter 29: Male sexual dysfunction in type 2 diabetes

ASSESSMENT OF SEXUAL FUNCTION IN PATIENTS UNDERGOING VASECTOMY USING THE INTERNATIONAL INDEX OF ERECTILE FUNCTION

Impact of Ankylosing Spondylitis on Erectile Function

REVIEW The relationship between hypogonadism and erectile dysfunction

ORIGINAL ARTICLE Recreational use of erectile dysfunction medication may decrease confidence in ability to gain and hold erections in young males

ERECTILE DYSFUNCTION ETIOLOGY AND HORMONAL CHANGES Minireview

An analysis of treatment preferences and sexual quality of life outcomes in female partners of Chinese men with erectile dysfunction

Sexual Health and Dysfunction in the Elderly. Nadya S. Dávila Lourido, MD September 28, 2018

Transcription:

www.kjurology.org DOI:10.4111/kju.2011.52.6.416 Sexual Dysfunction Correlation between Serum Total Testosterone and the AMS and IIEF Questionnaires in Patients with Erectile Dysfunction with Testosterone Deficiency Syndrome Jae Il Kang, Byeong Kuk Ham, Mi Mi Oh, Je Jong Kim, Du Geon Moon Department of Urology, Korea University Medical Center, Seoul, Korea Purpose: This study was conducted to investigate the relationship between serum total testosterone levels and scores on the Aging Male s Symptom (AMS) scale and the International Index of Erectile Function (IIEF) in men with erectile dysfunction with testosterone deficiency syndrome (TDS). Materials and Methods: From January 2005 to July 2008, 134 patients who complained of sexual dysfunction such as erectile dysfunction or decreased libido as the main symptoms of TDS with serum total testosterone levels less than 3.5 ng/ml were evaluated by independent t-test and linear regression analysis, respectively. Patients with treated hypogonadism within 6 months, with a history of taking a PDE5 inhibitor or an antidepressant for a depressive disorder, or who had metabolic syndrome were excluded from this study. Results: The AMS scale and its 3 subdomain scores were not significantly correlated with the total testosterone level. By contrast, the total IIEF score and the score of each IIEF domain except sexual desire showed a weakly significantly positive correlation with serum total testosterone. Conclusions: In TDS patients with erectile dysfunction, there was a low relationship between serum total testosterone levels and the AMS scale and a weakly positive correlation between total testosterone levels and all IIEF domains except sexual desire. There was a low relationship between the AMS scale, the sexual desire domain score of the IIEF, and total testosterone. We should understand these limitations when evaluating patients with erectile dysfunction with TDS. New scales should be developed for the evaluation of erectile dysfunction in these patients. Key Words: Erectile dysfunction; Questionnaires; Testosterone This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Article History: received 18 January, 2011 accepted 26 May, 2011 Corresponding Author: Du Geon Moon Department of Urology, Korea University Guro Hospital, 80, Gurodong, Guro-gu, Seoul 152-703, Korea TEL: +82-2-2626-3201 FAX: +82-2-2626-1321 E-mail: dgmoon@korea.ac.kr INTRODUCTION Late-onset hypogonadism or age-associated testosterone deficiency syndrome (TDS) in the aging male is defined as a clinical and biochemical syndrome characterized by a decline in levels of serum testosterone. With aging, men experience decreases in important health indicators like muscle amount, muscle power, physical activity, bone density, blood generation, and sexual drive [1]. Various research [2-4] on the decrease in blood testosterone with aging suggests that many clinical characteristics related to age, including erectile dysfunction (ED), are closely related to lack of testosterones. Recent research results indicate that testosterone and ED are closely related to one other [5,6], which suggests that supplementary therapy with testosterone may be one useful method in the treatment of ED. For such a reason, the European Association of Urology Guideline (EAU Guideline) recommends that patients who come to clinics with ED as their main complaint should all undergo testosterone value testing [7]. Korean Journal of Urology C The Korean Urological Association, 2011 416

AMS, IIEF Questionnaires in Patients with TDS 417 Although there is no established standard for the diagnosis of TDS, the 2006 recommendation by the Korean Society of Aging Male Research is a serum total testosterone level of less than 12 nmol/l (3.46 ng/ml) or a free testosterone value of less than 250 pmol/l (72 pg/ml) [8]. Furthermore, changes in male hormones with aging vary among individuals [9], and the relationship between the degree of age-related symptoms and the reduction of male hormones is not clear. Therefore, for easy clinical diagnosis of TDS, not only the concentration of blood testosterone but also subjective symptoms surveyed by questionnaire are very important. The Aging Male s Symptom (AMS) scale is the most widely used questionnaire for the diagnosis of TDS, but the AMS has been known to be nonspecific to low testosterone [10] because it was developed on the basis of a normal aging population. The International Index of Erectile Function (IIEF) is the most widely used questionnaire for the diagnosis and for assessing the treatment outcome of sexual dysfunction, but the IIEF has not been related to serum testosterone level because it was developed to evaluate the efficacy of phosphodiesterase-5 inhibitors (PDE5 inhibitors) in patients with ED [11,12]. Despite these limitations, the AMS and IIEF are commonly used to assess the efficacy of testosterone replacement therapy in ED patients with TDS. We performed this study to investigate the relationship between serum total testosterone levels and scores on the AMS scale and the IIEF and the threshold total testosterone level in relation to domains of the IIEF. MATERIALS AND METHODS This study was done on 134 outpatients in our clinics of urology with the main complaint of sexual dysfunction such as ED or decreased libido as the main symptom of TDS. The patients had a serum testosterone level less than 3.5 ng/ml and were evaluated from January 2005 to July 2008. Patients who received testosterone replacement therapy within 6 months, those taking type 5 phosphodiesterase (PDE5) inhibitors, those who were diagnosed with elderly depression and were taking anti-depressants, and those who had metabolic syndrome were excluded through gathering of disease history. Patients underwent measurement of blood total testosterones through a blood test. Blood was collected between 07:00 and 10:00 during an outpatient visit, at which time the patients also completed the AMS and IIEF questionnaires. The AMS scale was classified into three domains (psychological, somato-vegetative, and sexual) and the IIEF questionnaire sheet into five domains (erectile function, intercourse satisfaction, orgasmic function, sexual desire, and overall satisfaction). Serum total testosterone value, AMS total points and points for the three domains, and IIEF total points and points for the five domains were respectively analyzed. To determine the correlations of serum testosterone levels with scores on the IIEF and AMS scale, linear regression analysis was used and correlation coefficients and p-values were determined. To determine the threshold testosterone level, independent t-tests were also used with SPSS ver. 13.0 (SPSS Inc., Chicago, IL, USA). p-values of less than 0.05 were considered to be statistically significant. RESULTS The average age of the patients was 56.1±9.39 years, and the average value of serum total testosterones was 2.71± 0.76 ng/ml. In the AMS, the average value of the psychological symptom, somato-vegetative symptom, and sexual symptom domains were, respectively, 8.76±4.13, 14.7±5.80, and 14.2±4.48, and the average total points was 37.6±12.5. In the IIEF, the average values of each domain were, respectively, 11.9±7.54 for erectile function, 4.76±3.42 for TABLE 1. Characteristics of the patients Variables Mean±SD Age (yr) 56.1±9.39 Testosterone (ng/ml) 2.71±0.76 AMS scale Psychological factor 8.76±4.13 Somatovegetative factor 14.7±5.80 Sexual factor 14.2±4.48 Total score 37.6±12.5 IIEF questionnaire Erectile function 11.9±7.54 Intercourse satisfaction 4.76±3.42 Orgasmic function 4.61±3.40 Sexual desire 4.52±1.94 Overall satistaction 4.14±1.90 Total score 29.9±16.1 SD: standard deviation, AMS: Aging Male s Symptoms, IIEF: International Index of Erectile Function FIG. 1. Correlation of serum total testosterone and IIEF scores. TT: total testosterone, IIEF: International Index of Erectile Function.

418 Kang et al TABLE 2. Correlations of testosterone and multi-vocal factors in TDS patients Correlation coefficient p-value AMS scale Psychological factor 0.131 0.168 Somatovegetative factor 0.101 0.289 Sexual factor 0.015 0.875 Total score 0.095 0.318 IIEF questionnaire Erectile function 0.141 0.021 Intercourse satisfaction 0.126 0.049 Orgasmic function 0.173 0.018 Sexual desire 0.127 0.561 Overall satisfaction 0.099 0.040 Total score 0.124 0.034 TDS: testosterone deficiency syndrome, AMS: Aging Male s Symptoms, IIEF: International Index of Erectile Function sexual satisfaction, 4.61±3.40 for orgasmic function, 4.52± 1.94 for sexual drive, and 4.14±1.90 for overall satisfaction with sexual life, and the average total points was 29.9±16.1 (Table 1). In the correlation analysis, serum total testosterone was not significantly correlated with the AMS total score or its 3 subdomains (p>0.05). Serum total testosterone showed a significant weakly positive correlation (r=0.124, p=0.034) with the IIEF total score (Fig. 1), and among the 5 domains, the domains of erectile function, intercourse satisfaction, orgasmic satisfaction, and overall satisfaction with sexual life also showed significant weakly positive correlations with serum total testosterone (p<0.05). However, the sexual drive domain did not show any correlation with serum total testosterone (Table 2). DISCUSSION Reduction in blood total testosterones with aging was described for the first time by Hollander et al in the late 1950s and was verified in various cross-sectional studies and longitudinal studies [13-18]. Reduction of androgen accompanied by aging can cause physiological, somato-vegetative, and sexual symptoms, and the sexual symptoms include hyposexuality, ED, reduction of orgasmic function, and reduction of ejaculation amount and ejaculation force [19-21]. Testosterone deficiency causes sexual dysfunction and anatomical, physiological, and biochemical substrate damage of erectile function and affects the erection mechanism in the penis organ but can be recovered through testosterone supplementation therapy. Some study results have indicated that aged males require higher concentrations of testosterones for normal sexual function than do young people. These findings support the importance of male hormones as represented by testosterone regarding the sexual dysfunction that occurs with aging [22]. Sexual hormones are widely studied under the assumption that sexual dysfunction symptoms are related to the conditions of sexual hormones, but some patients with sexual dysfunction remain within the normal range of blood testosterone values [19-21]. Therefore, the correlation between high age itself and symptoms caused by aging leaves potential for argument, because aging-related symptoms can be affected by various causes such as hereditary factors, living habits, physical activity, nutritional status, and chemical dosage and accompanying diseases as well as endocrine changes. For such reasons, whether a patient s symptoms are alleviated as well as blood testosterone concentration is marked in a self-administered symptom score table, but in practice there is no internationally recognized method of diagnosis that can be used for the determination of diagnosis and treatment progress. The most frequent reason that patients with reduced male hormone visit a urologist is sexual dysfunction, such as hyposexuality or reduction of sexual drive, and in this regard, the IIEF of Rosen et al and the sexual area of the AMS of Heinemann can be used [10,11]. In the present study, the AMS total score and the 3 subdomains showed a positive but not a significant correlation (p>0.05) with total testosterone. In 2005 Morley et al specified male hormone deficiency condition as 70 ng/ml or less of bioavailable testosterones and compared the questionnaires of the Androgen Deficiency in Aging Males (ADAM), the AMS, and the Massachusetts Male Aging Study (MMAS). The diagnostic sensitivities of each questionnaire were, respectively, 98%, 83%, and 60%, and the specificities were, respectively, 30%, 39%, and 59% [23]. It was reported that the patients who showed a positive reaction in each questionnaire showed a significant difference in free testosterone and bioavailable testosterones but did not show any difference in total testosterones. In addition, in 2005 Basar et al determined more than 29 points in the total score of the AMS to be a positive reaction accompanied with aging and defined less than 26 points in the IIEF as hyposexuality in 348 persons [24]. In the AMS survey, patients with a positive reaction had significant differences in age, DHEA-A, estradiol, and AMS total points and points for each range compared with patients who did not have a positive reaction. Patients with hyposexuality had significant differences in age, DHEA-S, FTI, IIEF points, and AMS points. However, total testosterone was not associated with any variable. As mentioned above, the AMS survey is often used to screen patients with a lack of male hormone by total testosterone, but has low singularity and is not associated with total testosterone. These results may be because in the AMS survey, the items are questions associated with aging and do not reflect deficient status of testosterone, and the male hormone value is not considered in the judgment of results. In the future, it is necessary to reevaluate the questions of the AMS survey and to correct and supplement them translated in Korean as a tool for the diagnosis and evaluation of age-associated TDS. The IIEF was designed to measure erection ability and to evaluate a medical effect of impotence. In 2006, Zitzmann

AMS, IIEF Questionnaires in Patients with TDS 419 et al analyzed the relationship between male menopause and blood testosterone values in 434 males aged 50-86 years old who suffered from the male menopause syndrome and reported that, according to reduced blood total testosterone value, syndromes such as sexual disinclination, obesity, lack of concentration, somnipathy, and impotence were significantly increased [25]. The study also disclosed that there were significant positive correlations between blood total testosterone and IIEF total points and the points in the four ranges of erection ability, sex satisfaction, orgasm, and general satisfaction for sex life. However, with regard to sexual desire, the testosterone value was not correlated and many patients had normal sexual desire. Actually, it is reported that the numerical testosterone value required to maintain sexual desire is somewhat low. Some have reported that the numerical value of testosterone was not largely associated with sexual desire, although others strived to disclose a correlation between the numerical value of testosterone and sexual desire [26]. Therefore, to evaluate sexual desire, the relationship of blood total testosterone with psychological factors such as stress and melancholy and chronic disease such as lack of sleep should be considered. This study analyzed correlations between blood total testosterone value and scores related to sexual function syndromes in hospital visitors with hyposexuality such as impotence and sexual disinclination. Our study differs from the existing domestic research carried out with male persons of more than a fixed age. It is a limit of the study that this was a quantitative analysis of the numerical value of male hormone with only the AMS and IIEF as tools for measuring syndromes. Our study does not reflect the diverse endocrine changes that had an effect on the syndromes because we measured only blood total testosterone as a method of biochemical diagnosis. Male hormone replacement therapy is now the main therapy of age-associated TDS. Therefore, it is thought that it is necessary to carry out a large-scale research study on the correlations between male hormone values and survey results before and after carrying out male hormone replacement therapy. There are many reports that other hormones such as free testosterone, bioavailable testosterone, E2, and DHEA-S are associated with clinical syndromes such as impotence. Therefore, it is necessary to carry out research including the above in the future. CONCLUSIONS In TDS patients with ED, there was a low relationship between serum total testosterone levels and the AMS scale and a weekly positive correlation between the total testosterone level and IIEF scores, except for sexual desire. Because there was a low relationship between the AMS, the sexual desire domain score of the IIEF, and total testosterone, we should understand these limitations of evaluating TDS patients with ED and develop a new scale to be used in the evaluation of these patients. Conflicts of Interest The authors have nothing to disclose. REFERENCES 1. Davidson JM, Chen JJ, Crapo L, Gray GD, Greenleaf WJ, Catania JA. Hormonal changes and sexual function in aging men. J Clin Endocrinol Metab 1983;57:71-7. 2. Harman SM, Metter EJ, Tobin JD, Pearson J, Blackman MR. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab 2001;86:724-31. 3. Pirke KM, Doerr P. Age related changes in free plasma testosterone, dihydrotestosterone and oestradiol. Acta Endocrinol 1975; 80:171-8. 4. Purifoy FE, Koopmans LH, Mayes DM. Age differences in serum androgen levels in normal adult males. Hum Biol 1981;53:499-511. 5. Yassin AA, Saad F. Treatment of sexual dysfunction of hypogonadal patients with long-acting testosterone undecanoate (Nebido). World J Urol 2006;24:639-44. 6. Yassin AA, Saad F. Improvement of sexual function in men with late-onset hypogonadism treated with testosterone only. J Sex Med 2007;4:497-501. 7. Wespes E, Amar E, Hatzichristou D, Hatzimouratidis K, Montorsi F, Pryor J, et al. EAU Guidelines on erectile dysfunction: an update. Eur Urol 2006;49:806-15. 8. Nieschlag E, Swerdloff R, Behre HM, Gooren LJ, Kaufman JM, Legros JJ, et al. Investigation, treatment, and monitoring of lateonset hypogonadism in males: ISA, ISSAM, and EAU recommendations. J Androl 2006;27:135-7. 9. Kelleher S, Conway AJ, Handelsman DJ. Blood testosterone threshold for androgen deficiency symptoms. J Clin Endocrinol Metab 2004;89:3813-7. 10. Heinemann LA, Zimmermann T, Vermeulen A, Thiel C. A new Aging Male's Symptoms' (AMS) scale. Aging Male 1999;2:105-14. 11. Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A. The international index of erectile function (IIEF): a multidimensional scale for assessment of erectile dysfunction. Urology 1997;49:822-30. 12. Chung TG, Lee TK, Chung S, Lee MS, Kim YS, Ahn TY. The Korean version of the International Index of Erectile Function (IIEF): reliability and validation study. Korean J Urol 1999;40: 1334-43. 13. Hollander N, Hollander VP. The microdetermination of testosterone in human spermatic vein blood. J Clin Endocrinol Metab 1958;18:966-71. 14. Matsumoto AM. Andropause: clinical implications of the decline in serum testosterone levels with aging in men. J Gerontol A Biol Sci Med Sci 2002;57:M76-99. 15. Morley JE, Perry HM 3rd. Androgen deficiency in aging men: role of testosterone replacement therapy. J Lab Clin Med 2000;135: 370-8. 16. Morley JE, Kaiser FE, Perry HM 3rd, Patrick P, Morley PM, Stauber PM, et al. Longitudinal changes in testosterone, luteinizing hormone, and follicle-stimulating hormone in healthy older men. Metabolism 1997;46:410-3. 17. Zmuda JM, Cauley JA, Kriska A, Glynn NW, Gutai JP, Kuller LH. Longitudinal relation between endogenous testosterone and cardiovascular disease risk factors in middle-aged men. A 13-year follow-up of former Multiple Risk Factor Intervention Trial participants. Am J Epidemiol 1997;146:609-17.

420 Kang et al 18. Feldman HA, Longcope C, Derby CA, Johannes CB, Araujo AB, Coviello AD, et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. J Clin Endocrinol Metab 2002;87:589-98. 19. Hafez B, Hafez ES. Andropause: endocrinology, erectile dysfunction, and prostate pathophysiology. Arch Androl 2004;50:45-68. 20. Morales A, Lunenfeld B. Investigation, treatment and monitoring of late-onset hypogonadism in males. Official recommendations of ISSAM. International Society for the Study of the Aging Male. Aging Male 2002;5:74-86. 21. Vermeulen A. Andropause. Maturitas 2000;34:5-15. 22. Gooren LJ, Saad F. Recent insights into androgen action on the anatomical and physiological substrate of penile erection. Asian J Androl 2006;8:3-9. 23. Morley JE, Perry HM 3rd, Kevorkian RT, Patrick P. Comparison of screening questionnaires for the diagnosis of hypogonadism. Maturitas 2006;53:424-9. 24. Basar MM, Aydin G, Mert HC, Keles I, Caglayan O, Orkun S, et al. Relationship between serum sex steroids and Aging Male Symptoms score and International Index of Erectile Function. Urology 2005;66:597-601. 25. Zitzmann M, Faber S, Nieschlag E. Association of specific symptoms and metabolic risks with serum testosterone in older men. J Clin Endocrinol Metab 2006;91:4335-43. 26. Bagatell CJ, Heiman JR, Matsumoto AM, Rivier JE, Bremner WJ. Metabolic and behavioral effects of high-dose, exogenous testosterone in healthy men. J Clin Endocrinol Metab 1994;79:561-7.