What is Erectile Dysfunction?
Erectile dysfunction (ED) is a sexual problem in men, defined as a persistent inability to obtain and sustain an erection for satisfactory sexual performance. The scientific consensus is that the condition is highly prevalent across the world and positively correlates with age.1 Approximately half of men between 40 to 70 years old describe some degree of ED, and men in their 70s have a fourfold increase in the prevalence of ED compared with men in their 20s.2,3
ED also associates closely with a plethora of comorbidities. Compared to groups without ED, men with ED report one or more other chronic health conditions significantly more (74% vs 48%), including diabetes (16% vs 6%), cardiovascular risk factors such as hypertension (32% vs 16%) and hyperlipidemia (28% vs 14%), and mental health conditions including depression (24% vs 15%) and anxiety (23% vs 17%). Obesity, metabolic syndrome, lower urinary tract infections, and COVID-19 are among other conditions associated with ED.4
Understanding Risk Factors
A risk factor is an individual attribute or characteristic that increases the likelihood of developing a particular negative health outcome. Although they may contribute, risk factors do not necessarily cause the outcome. Risk factors may simply indicate that a factor associates with an adverse health outcome and is a ‘proxy’ or ‘marker’ for other, true causes.5
In the case of ED, whether such associations are causally related is not always well established; nevertheless, these associations allow ED to act as an early predictor of many health conditions. In an ideal setting, health professionals should use ED to benefit holistic patient care and not treat it as an isolated concern.
Common Co-morbidities and Risk factors in Erectile Dysfunction
Cardiovascular disease and ED are two conditions that often coexist, with cardiovascular disease presenting the most common comorbid condition in men with ED.6 In studies of men with ED, the prevalence of concurrent cardiovascular disorders is approximately 26 - 32% (angina, 4 - 8%; other cardiovascular disorders, including hypertension, 22 - 24%).7
The bulk of evidence suggests that the presence of ED is a good predictor of later diagnoses of cardiovascular disease and related events.8 Men with moderate or severe ED have a 43–65% greater incidence of coronary heart disease and experience more cardiovascular events within ten years compared to men without ED.6 Severe erectile dysfunction has also been shown to increase the risk of cardiovascular disease more so than moderate erectile dysfunction. In experiments such as the COBRA trial, for example, patients with more severe ED had more plaque deposited in the coronary arteries than patients with mild or moderate ED.9
The symptoms of ED tend to precede the clinical manifestations of cardiovascular disease by approximately 3–5 years. The difference in onset time is thought to be explained by the smaller average size of penile arteries compared to coronary arteries (1–1.5 mm versus 2.7–4.3 mm), such that blood flow to penile arteries is probably impaired earlier than in larger arteries. Damage to the lining of blood vessels also associates intimately with ED and may be another important factor.10 For these reasons, current guidelines of the British Society for Sexual Medicine recommend that men with ED should be thoroughly screened and treated for cardiovascular risk factors—the 3 - 5 year period is considered a ‘window of opportunity’ for the early treatment of cardiovascular risk factors.11
Obesity and Erectile Dysfunction
Obesity and ED are closely associated. Comprehensive reviews report that approximately 79% of men with ED are above the healthy BMI range.12 Men with obesity have also been found to have an approximate 60% (1.6) increased risk of ED compared to ‘normal weight’ groups.13 As the strongest research still finds a significant association between obesity and ED even after removing the effect of other causal factors, such as age, cardiovascular disease, and type 2 diabetes, there is some evidence to suggest the association may be causal.14 Moreover, highly controlled experiments show that weight loss via lifestyle change or surgery significantly improves erectile function in overweight and obese men, with a strength of effect that corresponds with the amount of weight loss.15,16
Type 2 Diabetes
Since obesity—or at least an excess of body fat—is considered the primary cause of type 2 diabetes, it is unsurprising that type 2 diabetes also associates with ED. Approximately 20% of men with ED have some form of diabetes, and more than half of men with diabetes are affected by ED.2,17 Compared to non-diabetics, men with type 2 diabetes have 66.3% higher incidence of erectile dysfunction. Extensive studies have even found that the risk of ED increases when treatment for type 2 diabetes has been successful. Due to what is known as “metabolic memory”, the deleterious effects of early exposure to high blood sugar may continue to cause issues in later life.18
An emerging trend is that men with diabetes develop ED 10–15 years earlier than those without diabetes. A couple of primary mechanisms are thought to explain such a trend. Firstly, the main features of type 2 diabetes, high blood sugar and insulin resistance, promote several abnormalities in the cardiovascular and nervous systems that can damage nerves and blood vessels in and around the penis. Secondly, high amounts of body fat around visceral organs, typically observed in people with type 2 diabetes, collectively represent one of the main risk factors for low testosterone levels (known as hypogonadism). Like cardiovascular diseases, ED is considered a marker symptom for diabetes and those with the sexual condition are recommended to have a diabetes screening.19
Metabolic syndrome is a cluster of risk factors for diabetes and cardiovascular disease, including central obesity, glucose intolerance, dyslipidemia, and elevated blood pressure. Current estimations are that a considerable 79 – 96% of patients with metabolic syndrome present with ED. On the flip side, 29 – 66% of patients with ED have metabolic syndrome. Compared to the prevalence of ED in the general population, this means that ED is up to two to three times more prevalent in men with metabolic syndrome than without.20
Lower Urinary Tract Symptoms
There are strong associations between sexual dysfunction and lower urinary tract symptoms independent of other sexual dysfunction risk factors such as age and diabetes.21 A review of relevant scientific evidence posits that roughly one-third of men aged over 50 years present ED and lower urinary tract symptoms in combination, and that most men seeking clinical treatment for either condition will present with both conditions.22 A few primary studies in the area have also found that lower urinary tract symptoms increase the odds of ED between 2.3–8.9, a strength of association similar to the impact of ageing on ED.23
There is an association between COVID-19 infections and the new onset of ED in men. Early evidence in small populations indicated that the number of patients diagnosed with ED during the pandemic was significantly higher during COVID-19 compared to the pre-pandemic period.24 Since then, a range of studies highlight that the odds of having a diagnosis for ED are 20–28% higher if the patient has a prior COVID-19 diagnosis.25 These associations appear to remain even after consideration of other factors that causally relate to sexual health. Indeed, laboratory studies show that patients who have contracted COVID-19 have a greater concentration of viral particles in the penile region compared to those who have not.26
Approximately 20% of patients with anxiety disorders report ED. In men with more severe erectile impairment, the psychological impact of ED tends to be greater.27,28 To what extent psychiatric disorders that co-exist with anxiety (e.g. post-traumatic stress disorder) contribute to this association is partly unknown, as is the potential interference from psychotropic medications which are commonly used to treat anxiety.29,30
Depression, which is known to reduce quality of life, has a frequency ranging from 10-25% in patients with ED.31 The relationship between these two factors has shown to be bidirectional–exposure to depression increases the risk of ED by 39%, and exposure to ED increases the risk of depression by 192%.32 Multiple lines of evidence also show that patients who are able to reverse depression are more likely to normalise their erectile capacity; likewise, men who receive ED therapies tend to have lower rates of depression compared to those who do not.33,34
Professional diagnosis is important
These comorbidities can serve as useful clinical markers for healthcare professionals to help identify ED in their patients. For men who suspect or who are struggling with ED, it’s essential to visit a healthcare professional to receive the correct diagnosis and if necessary, treatment.
- ED is associated with many co-morbidities
- ED tends to be considered as a consequence of certain chronic diseases, such as cardiovascular disease, type 2 diabetes, metabolic syndrome, and obesity. However, ED may contribute to mental health conditions such as anxiety and depression
- In addition to treating ED directly, health professionals should use ED as a risk marker for identifying and possibly treating chronic diseases
- McCabe MP, et al. J Sex Med 2016;13(2):144–52.
- Goldstein I, et al. Sex Med Rev 2020;8(1):48–58.
- Nguyen HMT, et al. Sex Med Rev 2017;5)4:508–520.
- Li JZ, et al. Int J Clin Pract 2022.doi:10.1155/2022/5229702
- Vaz D, et al. Rev Port Cardiol 2005;24(1):121–31.
- Thompson IM, et al. JAMA 2005;294(23):2996–3002.
- Haro JM, et. J Sex Med 2006;3(5):530–40.
- Raheem OA, et al. Am J Mens Health 2017;11(3):552–563.
- Montorsi P, et al. Eur Heart J 2006;27(22):2632–9.
- Gratzke C, et al. J Sex Med 2010;7(1):445–75.
- Hackett G, et al. J Sex Med 2018;15(4):430–457.
- Kaya E, et al. J Sex Med 2015;12(4):856–75.
- Pizzol D, et al. Rev Endocr Metab Disord 2020;21(3):657–666.
- Bacon CG, et al. J Urol 2006;171(1):217–1`.
- Li H, et al. Andrologia 2022;54(1).
- Aleid M, et al. J Sex Med 2017;14(2):205–214.
- Kouidrat Y, et al. Diabet Med 2017;34(9):1185–1192.
- Hui J, et al. Andrology 2021;9:288–296.
- Sairam K, et al. BJU Int 2002;88(1):68–71.
- Sanjay S, et al. Indian J Endrocrinol Metab 2015;19(2):277–282.
- Rosen R, et al. Eur Urol 2003;44(6):637–49.
- Seftel AD, et al. Int J Clin Pract 2013;67(1):32–45.
- Shiri R, et al. Int J Impot Res 2007;19(3):317–20.
- Duran MB, et al. Sex Med 2001;9(1):100292.
- Chu YK, et al. Sex Med 2022;10(1):100478.
- Kresch E, et al. World J Mens Health 2021;39(3):466–469.
- Velurajah R, et al. Int J Impot Res 2022;34(2):177–186.
- Latini DM, et al. J Urol 2002;168(5):2086–91.
- Kotler M, et al. Psychother Psychosom 2000;69(6):309–15.
- Montejo AL, et al. World Psychiatry 2018;17(1):3–11.
- Seftel AD, et al. J Urol 2004;171(1):2342–5.
- Lui Q, et al. J Sex Med 2018;15(8):1073–1082.
- Seagraves RT. Postgrad Med 2000;107(6):24–7.
- Nackeeran S, et al. J Sex Med 2021;18(12):2005–2011.