# Conditions often blamed for ED, and what the evidence shows > The evidence varies. Large records studies found new ED diagnoses somewhat more often in men after COVID-19, though they cannot show the virus was the cause. Hernia repair was followed by new sexual problems in about 5% of men in pooled studies. Parkinson's and epilepsy are linked to ED in research; for anemia and dehydration, direct evidence is thin. _Last updated: 2026-10-18_ --- **In short:** when erections change, it is natural to look back at whatever else happened recently: a bout of COVID-19, a hernia operation, a new diagnosis. Some of those links hold up in research and some barely have any research behind them. None of the conditions on this page appears on the NIH's list of the most common conditions that lead to ED ([NIDDK, Symptoms & Causes of ED](https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/symptoms-causes)), which is why they are worth checking one at a time. This page sets out what the studies found, how strong each kind of study is, and what the evidence cannot tell you about your own situation. | Condition | What the studies found | Kind of evidence | How much weight it carries | | ---------------------- | ---------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- | --------------------------------------------------------- | | COVID-19 | New ED diagnoses about 20% to 27% higher odds or risk after infection in two large US records studies | Retrospective insurance and health-record studies; one meta-analysis | Consistent link, modest size; cause not shown | | Inguinal hernia repair | New sexual problems in about 5% of men after repair; average erection scores held steady or rose in two small studies | Meta-analysis of 12 studies; two single-hospital before-and-after studies | Reasonable for a surgical topic; definitions vary | | Parkinson's disease | NINDS says it can affect sexual function; in two cohorts, men with ED were later diagnosed with Parkinson's more often | Government guidance; two observational cohorts | Linked in guidance and studies; which comes first is open | | Epilepsy | Men with ED were more likely to have a prior epilepsy diagnosis; pooled studies show more sexual problems in epilepsy | One large case-control study; a meta-analysis of 9 small studies | Moderate, mostly about sexual function in general | | Anemia | No cohort study of iron-deficiency anemia and ED found; indirect evidence from thalassemia and kidney dialysis | One cohort with few cases, one cross-sectional study, one review | Thin | | Dehydration | No study found; one letter to a journal editor | Opinion | None | ## Can COVID cause erectile dysfunction? Studies show a link, but they have not shown that the virus itself causes ED. A University of Utah team used a US commercial insurance claims database covering January 2020 to January 2021 and found that men with a prior COVID-19 infection were more likely to receive a new ED diagnosis than men without one, a hazard ratio of 1.27 (95% confidence interval 1.09 to 1.47), after adjusting for diabetes, heart disease, smoking, obesity, low testosterone and other factors. In that study, 42,406 of the 87,525 men had had COVID-19 ([Hebert et al., Int J Impot Res 2023](https://pmc.ncbi.nlm.nih.gov/articles/PMC10015534/)). A second team, at the University of Miami, used the TriNetX network of US health records, excluded men who already had ED, and matched 230,517 men with COVID-19 to 232,645 men without it by age, race, body mass index and several heart and metabolic conditions. COVID-19 was associated with ED with an odds ratio of 1.20 ([Chu et al., Sex Med 2022](https://pubmed.ncbi.nlm.nih.gov/34931145/)). In plain terms, both studies found the odds or risk of a new ED diagnosis roughly 20% to 27% higher after COVID-19. That is a modest difference, and it is a statement about large groups of men, not a prediction for any one man. ## How strong is the evidence linking COVID-19 and ED? It is consistent across studies but limited in ways the authors spell out themselves. The Utah team notes that home and untracked tests were not captured, that it could not measure how severe each infection was, and that its data covered only the early pandemic, which limited follow-up. The Miami team lists a retrospective design and no data on how severe either the ED or the infection was ([Hebert et al., 2023](https://pmc.ncbi.nlm.nih.gov/articles/PMC10015534/); [Chu et al., 2022](https://pubmed.ncbi.nlm.nih.gov/34931145/)). A 2023 meta-analysis pooled 8 studies, 4 of them with a comparison group. It estimated ED in 33% of people who had COVID-19, but the studies disagreed so much (a heterogeneity figure of over 99%) that the single number means little. Studies that measured ED with a questionnaire found far more of it (46%) than studies that counted diagnosis codes (9%). The pooled relative risk compared with people who had not had COVID-19 was 2.64, with a confidence interval running from 1.01 to 6.88, which is wide. Of the risk factors the authors could pool, only anxiety was linked to ED ([Zhang et al., J Endocrinol Invest 2023](https://pubmed.ncbi.nlm.nih.gov/36307637/)). A Japanese survey of 609 men who had been hospitalized with COVID-19 found that 116 (19.0%) reported ED at one or two years afterward. Of those, 25.0% said it improved during the two years and 49.1% saw no clear improvement. The authors note that it relied on self-report, did not use a standard erection questionnaire, and studied only hospitalized patients ([Kato et al., Sci Rep 2025](https://pmc.ncbi.nlm.nih.gov/articles/PMC11842839/)). It also had no comparison group of men who had not had COVID-19, so it cannot say how much of that ED would have appeared anyway. Stress and anxiety can affect erections in their own right, which is one reason these numbers are hard to read; our guide to [stress, PTSD and ED](/stress-ptsd-and-ed) covers that side. ## Can hernia surgery cause ED? For most men, studies suggest it does not, but a minority report new sexual problems or pain afterward. A 2020 systematic review in the Journal of the American College of Surgeons pooled 12 studies covering 4,884 patients who had an inguinal (groin) hernia repaired. New sexual problems after surgery, mostly defined as trouble completing intercourse, occurred in 5.3% (95% CI 3.6% to 7.9%), and pain with sexual activity, including pain with erection or ejaculation, in 9.0%. Rates of sexual problems were 7.8% after minimally invasive repair and 3.7% after open repair, while pain with sexual activity ran 7.4% and 12.5%. The authors conclude that these problems "are not rare" and belong in the conversation before surgery ([Ssentongo et al., J Am Coll Surg 2020](https://pubmed.ncbi.nlm.nih.gov/31733327/)). Studies that scored erectile function with a questionnaire before and after surgery found average scores holding steady or rising. In a Turkish study of 47 men having an open mesh repair, the erectile function score on the International Index of Erectile Function rose from 19.87 before surgery to 21.6 at one month and 23.86 at six months, and when asked why, 75% pointed to less pain ([Sönmez et al., Cent European J Urol 2016](https://pmc.ncbi.nlm.nih.gov/articles/PMC4986302/)). A 2026 study of 126 men found a small average rise in IIEF-5 scores at six months, from 22.85 to 23.35, with no difference between laparoscopic and open repair. Its authors call the rise small and say their results do not imply that surgery caused the change ([Sayur et al., J Clin Med 2026](https://pmc.ncbi.nlm.nih.gov/articles/PMC13301550/)). If erections changed after a hernia operation, the timing and any groin pain are useful details to bring to the surgeon or a urologist. ## Is Parkinson's disease linked to ED? Yes. The National Institute of Neurological Disorders and Stroke (NINDS) says Parkinson's disease "can affect sexual function because it changes how the brain and nerves control the body," and that Parkinson's-related depression or certain medicines may also lower sex drive ([NINDS, Parkinson's Disease](https://www.ninds.nih.gov/health-information/disorders/parkinsons-disease)). What research has looked at is the order. In the Health Professionals Follow-up Study, 32,616 men without Parkinson's in 1986 later answered a questionnaire about their past erectile function. Men who reported ED before 1986 were 3.8 times as likely to be diagnosed with Parkinson's between 1986 and 2002 as men who reported very good erectile function (95% CI 2.4 to 6.0) ([Gao et al., Am J Epidemiol 2007](https://pubmed.ncbi.nlm.nih.gov/17875583/)). A Taiwanese insurance study followed 3,153 men newly diagnosed with ED and 12,612 men without it. Parkinson's was diagnosed at 3.44 versus 1.64 cases per 1,000 person-years, an adjusted hazard ratio of 1.52 ([Yang et al., J Clin Neurol 2017](https://pubmed.ncbi.nlm.nih.gov/28748676/)). Those figures need careful reading. The absolute rate in the ED group was still small, and the first study relied on men recalling their erections years later. Neither study shows that ED leads to Parkinson's, and ED on its own is not a sign that someone has it. Our guide to [nerve conditions and ED](/nerve-conditions-and-ed) covers the conditions where the nerve link is better established. ## Is epilepsy linked to ED? Research links them, though most of it measures sexual problems in general. NINDS describes epilepsy as a chronic brain disorder in which groups of nerve cells sometimes send the wrong signals and cause seizures ([NINDS, Epilepsy and Seizures](https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures)). A Taiwanese population study compared 6,427 men diagnosed with ED to 32,135 men without it. After adjusting for high blood pressure, diabetes, high cholesterol, kidney disease, heart disease, obesity, alcohol misuse and income, men with ED were more likely to have had a prior epilepsy diagnosis, an odds ratio of 1.83 (95% CI 1.51 to 2.21) ([Keller et al., J Sex Med 2012](https://pubmed.ncbi.nlm.nih.gov/22429815/)). A 2019 meta-analysis of 9 small studies found a higher risk of sexual problems in men with epilepsy, a pooled relative risk of 4.85, but only 3 studies covered men and the results varied between them ([Zhao et al., Seizure 2019](https://pubmed.ncbi.nlm.nih.gov/30639977/)). The adjustments listed in the Taiwanese study do not include seizure medicines, so it cannot separate the condition from its treatment. If you suspect a seizure medicine, NINDS is clear that stopping one should always be supervised by a health care professional ([NINDS](https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures)), and our guide to [medications that affect erections](/medications-that-affect-erections) covers that conversation. ## Can anemia cause ED? The direct evidence is thin. When we searched PubMed for this page, we did not find a cohort study that followed men with iron-deficiency anemia to see whether they develop ED more often. What exists is indirect. A 2018 review by researchers at Baylor College of Medicine explains that iron sits at the core of soluble guanylyl cyclase, the enzyme that nitric oxide acts on during an erection, and that in mice whose enzyme lacked that core, the arteries of the penis did not relax in response to nerve signals or nitric oxide. The same review notes that the human sexual problems it describes are tied to too much iron, as in iron overload disorders, rather than too little ([Gabrielsen et al., Curr Urol Rep 2018](https://pmc.ncbi.nlm.nih.gov/articles/PMC6902410/)). Two human studies sit nearby. A Taiwanese cohort found a 4.56-fold higher adjusted risk of ED in 588 men with transfusion-naive thalassemia, an inherited blood condition, than in 2,337 comparison men, but that rested on just 12 and 10 cases ([Chen et al., Medicine 2015](https://pubmed.ncbi.nlm.nih.gov/25837766/)). A cross-sectional study of 22 men at one hemodialysis unit found that lower hemoglobin and hematocrit tracked with poorer erection scores in men with kidney failure ([Adnyana et al., Arch Ital Urol Androl 2025](https://pubmed.ncbi.nlm.nih.gov/40583617/)), a group in which many other factors are also at work. Our guide to [chronic conditions and ED](/chronic-conditions-and-ed) covers kidney disease in more detail. ## Can dehydration cause ED? No study we could find has tested it. The only PubMed item that addresses it directly is a 2009 letter to the editor in The Journal of Sexual Medicine titled "Hydration increases tissue perfusion and thus erectile function" ([Thornton, J Sex Med 2009](https://pubmed.ncbi.nlm.nih.gov/19523036/)). A letter is an opinion published for discussion, not a study with participants and results, so there is no published evidence to say how hydration affects erections either way. Our guide to [sudden or temporary ED](/sudden-or-temporary-ed) covers the short-term causes that are better studied. ## Does a link in a study mean the condition caused my ED? No. Every study on this page is observational: it records which conditions show up together, not what causes what. Men who had COVID-19 or epilepsy may also differ in health, stress or medicines in ways a database cannot fully capture, and the authors of each study list limits of exactly that kind. NIDDK notes that ED can have different causes, including blood vessel, nerve and hormone conditions, certain medicines, and anxiety, depression or stress ([NIDDK](https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/symptoms-causes)), so more than one factor is often in play. Our guide to [how to read ED evidence](/how-to-read-ed-evidence) explains hazard ratios, odds ratios and confidence intervals, and our overview of [what causes ED](/what-causes-ed) covers the causes with the strongest evidence. If erections changed after an illness, an operation or a new diagnosis, tell the clinician who manages that condition, and say when the change started. Bring a list of everything you take, and do not stop a prescribed medicine on your own. A change in erections is worth raising even when the timing seems to explain it. ## The bottom line Two large US records studies found the odds or risk of a new ED diagnosis about 20% to 27% higher after COVID-19, a consistent but modest link that does not show the virus was the cause. Pooled studies found new sexual problems in about 5% of men after hernia repair, while average erection scores held steady or rose. Parkinson's disease and epilepsy are linked to ED in research, with open questions about direction and medicines. For anemia and dehydration, there is little or no direct evidence. Whatever the timing, a change in erections is worth raising with a clinician. ## Sources Every clinical statement on this page traces to a primary or government source: - [NIH NIDDK, Symptoms & Causes of Erectile Dysfunction (last reviewed October 2024)](https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/symptoms-causes): the most common conditions that can lead to ED; medicines and mental health issues that can cause or worsen ED. - [Hebert KJ, et al. Prior COVID-19 infection associated with increased risk of newly diagnosed erectile dysfunction (Int J Impot Res, 2023)](https://pmc.ncbi.nlm.nih.gov/articles/PMC10015534/): retrospective MarketScan claims cohort, January 2020 to January 2021; 42,406 of 87,525 men with prior COVID-19; adjusted hazard ratio 1.27 (95% CI 1.09 to 1.47); stated limitations. - [Chu KY, et al. COVID-19 Infection Is Associated With New Onset Erectile Dysfunction: Insights From a National Registry (Sex Med, 2022)](https://pubmed.ncbi.nlm.nih.gov/34931145/): TriNetX records; men with prior ED excluded; 230,517 versus 232,645 propensity-matched men; odds ratio 1.20; stated limitations. - [Zhang J, et al. Prevalence and risk factors of erectile dysfunction in COVID-19 patients: a systematic review and meta-analysis (J Endocrinol Invest, 2023)](https://pubmed.ncbi.nlm.nih.gov/36307637/): 8 studies; pooled ED 33% with very high heterogeneity; 46% by questionnaire versus 9% by diagnosis code; relative risk 2.64 (95% CI 1.01 to 6.88); anxiety the only pooled risk factor linked to ED. - [Kato H, et al. Prevalence of erectile dysfunction as long-COVID symptom in hospitalized Japanese patients (Sci Rep, 2025)](https://pmc.ncbi.nlm.nih.gov/articles/PMC11842839/): 609 men hospitalized with COVID-19; 116 (19.0%) reported ED at one or two years; 25.0% improved and 49.1% did not clearly improve; self-report and other stated limitations. - [Ssentongo AE, et al. Pain and Dysfunction with Sexual Activity after Inguinal Hernia Repair: Systematic Review and Meta-Analysis (J Am Coll Surg, 2020)](https://pubmed.ncbi.nlm.nih.gov/31733327/): 12 studies, 4,884 patients; new-onset sexual dysfunction 5.3% and pain with sexual activity 9.0%; rates by minimally invasive and open repair. - [Sönmez MG, et al. Does inguinal hernia repair have an effect on sexual functions? (Cent European J Urol, 2016)](https://pmc.ncbi.nlm.nih.gov/articles/PMC4986302/): 47 men, Lichtenstein repair; IIEF erectile function 19.87 before, 21.6 at one month, 23.86 at six months; 75% cited less pain. - [Sayur V, et al. Erectile Function Before and After Elective Inguinal Hernia Repair: A Paired IIEF-5 Study Comparing Laparoscopic and Open Techniques (J Clin Med, 2026)](https://pmc.ncbi.nlm.nih.gov/articles/PMC13301550/): 126 men; IIEF-5 22.85 to 23.35 at six months; no difference by technique; no causal effect implied. - [NIH NINDS, Parkinson's Disease (last reviewed July 23, 2026)](https://www.ninds.nih.gov/health-information/disorders/parkinsons-disease): how Parkinson's can affect sexual function; depression and medicines and sex drive. - [Gao X, et al. Erectile function and risk of Parkinson's disease (Am J Epidemiol, 2007)](https://pubmed.ncbi.nlm.nih.gov/17875583/): Health Professionals Follow-up Study, 32,616 men; ED before 1986 and later Parkinson's diagnosis, relative risk 3.8 (95% CI 2.4 to 6.0) versus very good erectile function; retrospective questionnaire. - [Yang Y, et al. Relationship between Erectile Dysfunction, Comorbidity, and Parkinson's Disease: Evidence from a Population-Based Longitudinal Study (J Clin Neurol, 2017)](https://pubmed.ncbi.nlm.nih.gov/28748676/): 3,153 men with ED and 12,612 without; 3.44 versus 1.64 Parkinson's cases per 1,000 person-years; adjusted hazard ratio 1.52. - [NIH NINDS, Epilepsy and Seizures (last reviewed March 13, 2026)](https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures): what epilepsy is; stopping antiseizure medicine only with professional supervision. - [Keller J, et al. Association between epilepsy and erectile dysfunction: evidence from a population-based study (J Sex Med, 2012)](https://pubmed.ncbi.nlm.nih.gov/22429815/): 6,427 men with ED and 32,135 controls; adjusted odds ratio 1.83 (95% CI 1.51 to 2.21) for prior epilepsy. - [Zhao S, et al. Association between epilepsy and risk of sexual dysfunction: A meta-analysis (Seizure, 2019)](https://pubmed.ncbi.nlm.nih.gov/30639977/): 9 studies; male sexual dysfunction from 3 studies, pooled relative risk 4.85. - [Gabrielsen JS, Lamb DJ, Lipshultz LI. Iron and a Man's Reproductive Health: The Good, the Bad and the Ugly (Curr Urol Rep, 2018)](https://pmc.ncbi.nlm.nih.gov/articles/PMC6902410/): iron at the core of soluble guanylyl cyclase; mouse findings; sexual problems tied to iron overload disorders. - [Chen YG, et al. Risk of erectile dysfunction in transfusion-naive thalassemia men: a nationwide population-based retrospective cohort study (Medicine, 2015)](https://pubmed.ncbi.nlm.nih.gov/25837766/): 588 men with thalassemia and 2,337 controls; 12 and 10 cases; adjusted 4.56-fold risk. - [Adnyana AANK, et al. Exploring the association between hemoglobin, hematocrit, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio with erectile dysfunction in chronic kidney disease patients undergoing hemodialysis: a cross-sectional study (Arch Ital Urol Androl, 2025)](https://pubmed.ncbi.nlm.nih.gov/40583617/): 22 men on hemodialysis; positive correlation between hemoglobin and hematocrit and erection scores. - [Thornton SN. Hydration increases tissue perfusion and thus erectile function (J Sex Med, 2009)](https://pubmed.ncbi.nlm.nih.gov/19523036/): a letter to the editor commenting on another paper. --- _Affiliate disclosure: some links on the web version of this site go to Bodybuilding Peptides (trybbpeptides.com), an affiliate destination, and we may earn a commission if you buy there. Our coverage is independent of that relationship. Details: https://theedreport.com/affiliate-disclosure/_