ISI Impact Factor (2004): 1.096

Editor-in-Chief
Prof. Yi-Fei WANG,

Prevalence and risk factors of erectile dysfunction in three cities of China: a community-based study

Quan Bai¹, Qing-Quan Xu¹, Hui Jiang¹, Wei-Li Zhang², Xing-Huan Wang³, Ji-Chuan Zhu¹

Asian J Androl  2004 Dec; 6: 343-348         

Keywords: erectile dysfunction; prevalence; risk factor; China

Abstract

Aim: To determine the age-adjusted prevalence of erectile dysfunction (ED) in 3 big cities of China and to explore its potential sociodemographic, medical and lifestyle correlates. Methods: A cross-sectional, population-based survey was conducted in three cities of China. Structured questionnaires were administered to 2 226 men, aged 20 - 86 years, by trained interviewers. Results: The age-adjusted prevalence of ED was 28.34 % (mild 15.99 %, moderate 7.14 %, severe 5.21 %). In the men above 40, the prevalence was 40.2 %. Age was positively correlated with ED (P<0.01). Education was negatively correlated with ED (P<0.01). Spouse companionship, living condition were positively correlated with ED (P<0.01). Histories of cardiovascular disease, diabetes, and hyperlipidemia were positively correlated with ED (P<0.01). Cigarette smoking was not correlated with ED (P>0.05), while the cigarette consumption and duration were positively correlated with ED (P<0.01). Alcohol drinking is negatively correlated with ED (P<0.01). The duration of drinking was positively correlated with ED (P<0.01). Weekly alcohol consumption was not correlated with ED (P>0.05). Conclusion: The prevalence of ED increased with age. Cardiovascular disease, diabetes and hyperlipidemia were positively correlated with the increased prevalence. Sociodemographic and lifestyle factors, such as education, spouse companionship, living condition, cigarette and alcohol consumption or duration also have association with the prevalence of ED.

1 Introduction

Erectile dysfunction (ED) has been defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual intercourse [1]. A community-based study carried out from 1987 to 1989 in Massachusetts, USA, indicated that the prevalence of ED was 52 % in men 40 to 70 years old. This study demonstrated that ED was strongly correlated with age and other risk factors [2]. Since then, many community-based studies on this subject were done in other countries, but the conclusions were not identical [3-12]. Recently, a brief review suggested that the prevalence range of ED in the European Union is 20 % - 45 % [13]. The present study was designed to observe the real prevalence of ED and associated risk factors for Chinese in three big cities, Beijing, Guangzhou and Chongqing, located in the northern , southern and western parts of China, respectively.

2 Materials and methods

A total of 2 226 men 20 to 86 years old from three cities in China (642 from Beijing, 574 from Guangzhou and 1 010 from Chongqing) were enrolled in the cross-sectional study. The community physicians were trained to administrate the questionnaires and interview the participants in person. In order to obtain complete and accurate information, the questionnaires were requested to be filled in and returned on the spot. Among the 2 226 sets of questionnaires, 23 were ineligible due to incomplete fulfillment.

The questionnaires include 4 sections:

(1) Sociodemographic information, including age, marital status, education, spouse companionship and living condition.

(2) General health and associated diseases, including cardiovascular diseases (hypertension, angina pectoris, etc.), diabetes and hyperlipidemia.

(3) Life style, including smoking and drinking. Smokers were classified by duration (<10, 10 - 20 and >20 years) and consumption (<10, 10 - 20 and >20 cigarettes/day). Alcohol drinkers were also classified by duration (<10, 10 - 20 and >20 years) and consumption (<100, 100 - 250 and >250 mL/week). The consumption of wine, beer or spirits was converted by their concentration into consumption of alcohol.

(4) Erectile function, general sexual performance and sex satisfaction. In order to make the erectile function (EF) in the questionnaires more comprehensible, the Chinese Index of Erectile Function-5 (CIEF-5) was adopted. CIEF-5 was framed by the Chinese urologists and andrologists for the purpose of accommodating to the Chinese tradition. CIEF-5 is derived from IIEF-5 and comprises of the following questions:

1. How often were you able to get an erection during sexual activity? (0=no sexual activity; 1=almost never/never; 2=a few times; 3=sometimes; 4=mostly; 5=almost always/always)

2. When you attempted sexual intercourse, how often were you able to penetrate (enter) your partner? (0=no sexual activity; 1=almost never/never; 2=a few times; 3 = sometimes; 4=mostly; 5=almost always/always)

3. During sexual intercourse, how often were you able to maintain your erection after you had penetrated (entered) your partner? (0=no sexual activity; 1=almost never/never; 2=a few times; 3=sometimes; 4=mostly; 5=almost always/always)

4. When you attempted sexual intercourse, how often was it satisfactory for you? (0=no sexual activity; 1=almost never/never; 2=a few times; 3=sometimes; 4 =mostly; 5=almost always/always)

5. How do you rate your confidence that you could get and keep an erection? (1=very low; 2=low; 3= moderate; 4=high; 5=very high).

The scores for various degree ED included mild (21-12), moderate (11-8) and severe (7-0).

Data on completed questionnaires (2 203) were entered into a computerized database with EPI Info software and analyzed with SPSS statistical software. For each independent variable, crude and age-adjusted odds ratio (OR) and 95 % confidence interval (CI) were calculated. Statistical significance was assessed by the c² test for categorical variables.

The age-adjusted prevalence of ED was 28.3 % (mild 15.99 %, moderate 7.14 % and severe 5.21 %). In men above 40 years, the prevalence was 40.2 %. The prevalence of ED increased with age (Table 1 and Figure 1) and age was positively correlated with ED (c²=259.12, P<0.01). The prevalence of ED decreased with the increase in the education level (Table 1 and Figure 2). The prevalence of ED was 63.59 %, 30.48 %, 24.72 % and 21.85 % in men with elementary school or lower, middle school, high school, and college or higher degrees, respectively. Education was negatively correlated with ED (c²=134.60, P<0.01).

Table 1. Sociodemographic, medical and lifestyle characteristics of 2 203 study subjects.

Figure 1. Association of subject age with ED prevalence imputed by discriminant analysis in 2 203 respondents to the sexual activity questionnaire.

Figure 2. Association of education level and the age-adjusted prevalence of ED.

The age-adjusted OR between ED and the potential covariates was shown in Table 2. In the sociodemographic variables, spouse companionship and living condition were positively correlated with ED (P<0.01); in the medical variables, histories of cardiovascular diseases, diabetes and hyperlipidemia were positively correlated with ED (P<0.01, Figure 3).

Table 2. Age-adjusted odds ratios for ED: sociodemographic, medical and lifestyle characteristics.

Figure 3. Association of self-reported disease with age-adjusted prevalence of ED. Dark boxes: subjects with disease. Light boxes: subjects without disease.

Of the lifestyle factors, smoking was not correlated with ED (c²=0.27, P>0.05), while the duration of smoking and the cigarette consumption were positively correlated with ED (P<0.01). The prevalence of ED elevated with the increase in cigarette consumption and duration (Figure 4). The risk of ED was higher in subjects having smoked for more than 10 years and in heavy smokers (daily cigarette consumption >20) than that in others. Alcohol drinking is negatively correlated with ED (P<0.01). The prevalence of ED was lower in drinkers than in nondrinkers. The duration of drinking was positively correlated with ED (P<0.01). The prevalence was significantly higher in subjects having drunk for more than 20 years than that in others. Weekly alcohol consumption was not correlated with ED (P>0.05, Figure 5).

Figure 4. Association of smoking, duration, and daily cigarette consumption with age-adjusted prevalence of ED. Black and white boxes: smoking or not. Dotted boxes: duration of smoking. Diagonal boxes: daily cigarette consumption.

Figure 5.  Association of drinking, duration, and weekly alcohol consumption with age-adjusted prevalence of ED. Black and white boxes: drinking or not. Dotted boxes: duration of drinking. Diagonal boxes: weekly alcohol consumption.

4 Discussion

Erectile functioning is a complex response requiring intact psychological, neural and vascular components. As far as the global prevalence of ED is concerned, there are reports ranging between 18.9 % and 69.2 % [3]. In the Pfizer Cross-National Study of Prevalence and Correlates of ED, the age-adjusted overall prevalence of ED was 81.1 % in Japan, 69.8 % in Italy, 62.1 % in Malaysia, and 39.9 % in Brazil [14].

In this study, age was positively correlated with ED. Of all risk factors selected, age had the strongest correlation with ED. This is similar to many studies conducted around the world where age was the single most important determinant of ED [3]. Besides physiological retrogression , aging also carries increased medical comor-bidity, such as cardiovascular disease, hypertension , diabetes, etc.

Education is another factor that is most likely selected by many investigators. The present data showed that education had a positive pertinence with the erectile function. Similar finding has been reached by other population-based studies [8]. In China, persons with lower education levels commonly pay less attention to healthcare and have unhealthy lifestyle, such as smoking, drinking, etc.

Cardiovascular disease was positively correlated with ED in this study. The prevalence of ED in patients with cardiovascular disease has been reported to be as high as 80 % [15]. The incidence of cardiovascular disease was directly proportional to the prevalence of ED in many studies and ED might be the first sign of a serious cardiovascular disease [3]. In the Massachusetts Male Aging Study (MMAS) study, some of the risk factors for cardiovascular disease, such as hypertension, smoking, obesity and dietary cholesterol and fat intake showed a prospective association with ED. Hyperlipidemia is another risk factor for cardiovascular disease and is closely correlated with obesity and dietary fat intake. Hyper-cholesterolemia may cause impairment of endothelium-dependent relaxation and oxidized LDL is the major causative cholesterol of the impaired relaxation response; A chain reaction, the production of superoxide radicals and functional impairment of eNOS may be a major cause of the functional impairment in the early stages of hyper-cholesterolemia [16]. This study also showed the positive relationship between hyperlipidemia and ED.

Diabetes is another well-recognized risk factor of ED. In this study, the prevalence of ED in patients with diabetes was two times higher than that of other individuals. In the MMAS, the age-adjusted probability of complete ED in subjects with treated diabetes was three times greater than those without diabetes [2]. In studies performed in diabetes populations, the reported prevalence of ED was between 50 % and 75 %. The severity and prevalence of ED increased with poor glycemic control , diabetic neuropathy, duration of disease and type II diabetes mellitus [17]. The direct cause of ED in diabetes patients has not been elucidated and vascular disease is the most frequently cited. Other factors are medications, autonomic neuropathy, gonadal dysfunction and impairment of neurogenic and endothelium mediated relaxation of penile smooth muscle [18].

4.3 Life style

The association between cigarette smoking and the risk of ED is confused in the present study. Subjects having smoked more than 20 years or consumed more than 20 cigarettes per day usually have higher prevalence of ED. In many other studies, cigarette smoking is an independent risk factor of ED. So it is difficult to detect the association between ED and smoking in cross-sectional studies. There have been many controversial reports on this aspect. The Health Professionals Follow-up Study [19] and MMAS [2] have not found any direct association between ED and smoking. However, cigarette smoking did increase the risk of vascular diseases linked to ED and may amplify many risk factors of ED, such as heart disease, hypertension, drug effect, etc [2].

Alcohol drinking was inversely correlated with ED in this study. The MMAS found a slightly elevated incidence of ED in alcohol consumers. The Health Professional Follow-up Study [19] showed that moderate drinkers have a lower incidence of ED than either nondrinkers or heavy drinkers. As we known, heavy alcohol consumption will lead to hepatic failure that in turn will impair the metabolism of estrogen. The present data suggested that long duration of drinking (over 20 years) significantly enhanced the risk of ED, while weekly alcohol consumption of less than 250ml has no association with the prevalence.

Psycho-environmental factors, such as spouse companionship and living condition, have ever been selected by other investigators [20]. Our data showed that both spouse companionship and living condition have association with the prevalence of ED. In developing countries, bad living conditions often impose adverse psychological effect on the sexuality and male erection. Also, as another important psychological factor of sexual activity, spouse companionship affects sexual desire and erectile function.

This is the first large multiple community-based assessment of ED in China; a survey in three big cities indicates that the overall age-adjusted prevalence of ED is 28.3 % and that ED is not only correlated with age, education and some organic diseases, but also to lifestyle and psycho-environmental factors.

The support of the study from Pfizer Pharmacy is kindly acknowledged.

References

[1] National Institutes of Health Consensus Development Panel on Impotence: Impotence. JAMA 1993; 270: 83-90.
[2] Feldman HA, Goldstein I, Hatzichristou DG, Krane RJ, Mckinlay JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol 1994; 151: 54-61.
[3] Nehra A, Kulaksizoglu H. Global perspectives and controversies in the epidemiology of male erectile dysfunction. Curr Opin Urol 2002; 12: 493-6.
[4] Kubin M, Wagner G, Fugl-Meyer AR. Epidemiology of erectile dysfunction. Int J Impot Res 2003; 15: 63-71.
[5] Nicolosi A, Moreira ED Jr, Shirai M, Bin Mohd Tambi MI, Glasser DB. Epidemiology of erectile dysfunction in four countries: cross-national study of the prevalence and correlates of erectile dysfunction. Urology 2003; 61: 201-6.
[6] Blanker MH, Bosch JL, Groeneveld FP, Bohnen AM. Prins A, Thomas S, Hop WC. Erectile and ejaculatory dysfunction in a community-based sample of men 50 to 78 years old: prevalence, concern, and relation to sexual activity. Urology 2001; 57: 763-8.
[7] Giuliano F, Chevret-Measson M, Tsatsaris A, Reitz C, Murino M, Thonneau P. Prevalence of Erectile Dysfunction in France: results of an epidemiological survey of a representative sample of 1 004 Men. Europ Urol 2002; 42: 382-9.
[8] Seyam RM, Albakry A, Ghobish A, Arif H, Dandash K, Rashwan H. Prevalence of erectile dysfunction and its correlates in Egypt: a community-based study. Int J Impot Res 2003; 15: 237-45.
[9] Mak R, De Backer GD, Kornitzer M, De Meyer JM. Prevalence and correlates of erectile dysfunction in a population-based study in Belgium. Europ Urol 2002; 41: 132-8.
[10] Akkus E, Kadioglu A, Esen A, Doran S, Ergen A, Anafarta K, et al. Prevalence and Correlates of Erectile Dysfunction in Turkey: A Population-Based Study. European Urology 2002; 41: 298- 304.
[11] Moreira ED Jr, Lisboa Lobo CF, Villa M, Nicolosi A, Glasser DB. Prevalence and correlates of erectile dysfunction in Salvador, northeastern Brazil: a population-based study. Int J Impot Res 2002; 14 (Suppl 2): S3-9.
[12] Shaeer KZ, Osegbe DN, Siddiqui SH, Razzaque A, Glasser DB, Jaguste V. Prevalence of erectile dysfunction and its correlates among men attending primary care clinics in three countries: Pakistan, Egypt, and Nigeria. Int J Impot Res 2003; 15 (Suppl 1): S8-14.
[13] Papatsoris AG, Triantafyllidis A, Gekas A. Prevalence of erectile dysfunction in the European Union. Asian J Androl 2003; 5: 255.
[14] Glasser DB, Sweeney M, Mckinlay JB. The prevalence of erectile dysfunction in four countries: Italy, Brazil, Malaysia, and Japan. In: Proceeding of the Eighth World Meeting on Impotence Research; 1998.
[15] Feldman HA, Johannes CB, Derby CA, Kleinman KP, Mohr BA, Araujo AB, et al. Erectile dysfunction and coronary risk factors: prospective results from the Massachusetts Male Aging Study. Prev Med 2000; 30: 328-38.
[16] Kim SC. Hyperlipidemia and erectile dysfunction. Asian J Androl 2000; 2: 161-6.
[17] Klein R, Klein BE, Lee KE, Moss SE, Cruickshanks KJ. Prevalence of self-reported erectile dysfunction in people with long-term IDDM. Diabetes Care 1996; 19: 135-41.
[18] Guay AT. Sexual dysfunction in the diabetic patient. Int J Impot Res 2002; 13 (Suppl 5): S47-50.
[19] Rimm EB, Bacon CG, Giovannucci EL, Kawachi I. Body weight, physical activity, and alcohol consumption in relation to erectile dysfunction among US male health professionals free of major chronic diseases. J Urol 2000; 163 (Suppl 4): 241.
[20] Meuleman EJ. Investigations in erectile dysfunction. Curr Opin Urol 2003; 13: 411-6.

home

Correspondence to: Prof. Ji-Chuan Zhu, Department of Urology, The People抯 Hospital, Peking University, Beijing 100044, China.
Tel: +86-010-6830 5875, Fax: +86-010-6830 5875
E-mail: zhjc1939@sina.com
Received 2004-04-01 Accepted 2004-07-17