Correlation between non-alcoholic fatty liver disease and erectile dysfunction: A systematic narrative review

Table 1 Characteristics of the studies included in the systematic review, n (%)/mean ± SD

Ref.	Country of origin	Study design	Time period	Participants (n)	NAFLD patients (n)	Mean age, years	BMI (kg/m2)	ED risk	Population	Diagnostic methods for NAFLD	Assessment tools for ED	Main findings
Tarik Kani et al[3], 2021	Turkey	Retrospective study	From 2017 to 2018	1362	684	48.65 ± 11.83	30.98 ± 6.43	68 (50.0)	Patients were diagnosed with NAFLD at a single gastroenterology outpatient clinic	Ultrasonography	IIEF-5	ED is common among patients with NAFLD. Age, obesity, and hypertension are also associated with ED in these patients
				03	685	42.63 ± 10.52	29.02 ± 3.55
Youcheng et al[10], 2025	China	Cross-sectional study	From 2001 to 2004	14982	4834	51.5 ± 18.6	28.0 ± 5.6	483 (32.2)	Adult males who participated in the 2001-2004 National Health and Nutrition Examination Survey in the United States	US-FLI score	Answer the questions	Participants with NAFLD had a significantly increased risk of developing ED compared with those without fatty liver disease
				22653	10155
Duman et al[11], 2016	Turkey	Prospective study	20151	402	134	38.3 ± 11.2	27.88 ± 3.13	13 (32.5)	Male NAFLD patients aged 18 years to 75 years	Biopsy	IIEF-5	There is a significant association between NAFLD and ED
				03	275	41.0 ± 9.8	28.62 ± 3.66
Yilmaz et al[12], 2021	Turkey	Cross-sectional study	From February 2018 to January 2019	1062	744	51.47 ± 10.34	28.51 ± 3.57	74 (69.8)	Male patients presenting to the urology outpatient clinic with symptoms of erectile dysfunction	Ultrasonography	IIEF-5	NAFLD is a significant risk factor for ED. Patients with NAFLD are 292 times more likely to experience ED than those without NAFLD
				403	325
Eren and Horsanali[13], 2019	Turkey	Retrospective study	From January 2016 to March 2018	2562	NA4	61.02 ± 9.27	27.4 ± 3.5	NA	Male patients are diagnosed with lower urinary tract symptoms or benign prostatic hyperplasia	Ultrasonography	IIEF-5	NAFLD is an independent predictor of IIEF-5 scores. The severity of NAFLD is negatively correlated with IIEF-5 scores
				1003	NA5		29.67 ± 4.16
Hasanain et al[14], 2017	Egypt	Prospective study	From April 2013 to February 2015	1922	884	42.4 ± 7.7	NA	88 (45.8)	A series of male patients with NAFLD were admitted across multiple disciplines	Ultrasonography	IIEF-5	ED is a common condition among male NAFLD patients. Insulin resistance and low serum testosterone levels jointly contribute to its development
				03	1045
Ragab et al[15], 2024	Egypt	Observational study	From November 2021 to November 2022	712	414	38.9 ± 10.3	26.91 ± 3.12	41 (57.7)	NAFLD patients with normal liver function and NAFLD patients with abnormal liver function	Ultrasonography	IIEF-5	Abnormal levels of nitric oxide and adropin may play a potential role in the development and progression of erectile dysfunction in patients with nonalcoholic fatty liver disease
				943	305	39.1 ± 10.7	27.26 ± 3.63

¹Manuscript receipt date.

²Non-alcoholic fatty liver disease.

³Without non-alcoholic fatty liver disease.

⁴Erectile dysfunction.

⁵Without erectile dysfunction.

NAFLD: Non-alcoholic fatty liver disease; ED: Erectile dysfunction; BMI: Body mass index; US-FLI: Ultrasonographic fatty liver index; IIEF-5: Five-item version of the International Index of Erectile Function; NA: Not available.

Table 2 Quality assessment of the studies included in the systematic review

Ref.	Study design	Assessment tools	Assessment results	Interpretation of results
Tarik Kani et al[3], 2021	Retrospective study	NOS	7 stars	The maximum total score is nine stars. A score of seven or more stars generally indicates high-quality research, while a score of five or six stars indicates medium quality, and a score of less than five stars indicates low quality
Youcheng et al[10], 2025	Prospective study	NOS	6 stars
Duman et al[11], 2016	Retrospective study	NOS	6 stars
Yilmaz et al[12], 2021	Prospective study	NOS	7 stars
Eren and Horsanali[13], 2019	Cross-sectional study	AHRQ	8 points	This standard comprises 11 items, each of which is answered with “Yes”, “No”, or “Uncertain”. A “Yes” response earns 1 point. A total score of 0-3 indicates low quality, 4-7 indicates medium quality, and 8-11 indicates high quality
Hasanain et al[14], 2017	Cross-sectional study	AHRQ	7 points
Ragab et al[15], 2024	Observational study	AHRQ	6 points

NOS: Newcastle-Ottawa Scale; AHRQ: Agency for Healthcare Research and Quality.

Table 3 Factors influencing the development of erectile dysfunction in non-alcoholic fatty liver disease patients

Ref.	Influencing factors	Conclusions
Tarik Kani et al[3], 2021	Age, obesity, hypertension	Older age, obesity, and hypertension are associated with ED in the NAFLD cohort
Youcheng et al[10], 2025	US-FLI	NAFLD is positively correlated with ED
Duman et al[11], 2016	NAFLD score	There is a significant association between NAFLD and ED
Yilmaz et al[12], 2021	Age, MetS, NAFLD score	As NAFLD-related liver damage progresses, symptoms of ED show a significant worsening trend
Eren and Horsanali[13], 2019	Age, MetS, NAFLD score	The higher the NAFLD grade, the lower the IIEF-5 score
Hasanain et al[14], 2017	Age ≥ 40 years, IR, low serum testosterone	Age, insulin resistance, and low serum testosterone levels are independently associated with ED
Ragab et al[15], 2024	Serum adropin, creatinine, GAD-7 score	GAD-7 scale scores, creatinine levels, and adropin were the only strong independent predictors of IIEF-5 scores

US-FLI: Ultrasonographic fatty liver indicator; NAFLD: Non-alcoholic fatty liver disease; ED: Erectile dysfunction; MetS: Metabolic syndrome; IR: Insulin resistance; GAD-7: Generalized anxiety disorder-7; IIEF-5: Five-item version of the International Index of Erectile Function.