Association of oxidative stress with erectile dysfunction in community-dwelling men and men on dialysis

Figures & data

Figure 1. Participant selection of community-dwelling men. The number of included and excluded participants is shown. ED: erectile dysfunction.

Flowchart of the participant selection of community-dwelling men. Of 431 men, 33 were excluded. Of the remaining 398 men, one-fourth of men reported severe erectile dysfunction.

Figure 2. Participant selection of men on dialysis. The number of included and excluded patients is shown. PD: peritoneal dialysis; HD: hemodialysis; ED: erectile dysfunction; 8-OHdG: 8-hydroxy-2'-deoxyguanosine.

Flowchart of the participant selection of men on dialysis. Of 186 men, 144 were excluded. Of the remaining 42 men, two-third of men reported severe erectile dysfunction.

Table 1. Characteristics of community-dwelling men.

	All n = 398	Non-ED group n = 66	Mild/ moderate ED group n = 233	Moderate/ severe ED group n = 99	p Value
Age, years	54 (39–65)	37 (32–44)	51 (39–63)	66 (61–73)	<0.001
Body mass index, kg/m^2	23 (22–26)	23 (21–25)	23 (22–26)	24 (22–26)	0.969
Hypertension	167 (42%)	13 (20%)	96 (41%)	58 (59%)	<0.001
Dyslipidemia	128 (32%)	15 (23%)	68 (29%)	45 (46%)	0.003
Diabetes mellitus	42 (11%)	2 (3.0%)	21 (9.0%)	19 (19%)	0.002
Antidiabetic medications
Insulin	2 (0.5%)	0 (0.0%)	0 (0.0%)	2 (2.0%)	0.089
α-glucosidase inhibitors	3 (0.8%)	0 (0.0%)	2 (0.9%)	1 (1.0%)	1.000
Biguanides	7 (1.8%)	0 (0.0%)	5 (2.1%)	2 (2.0%)	0.751
DPP-4 inhibitors	11 (2.8%)	0 (0.0%)	5 (2.1%)	6 (6.1%)	0.060
Sulfonylureas	3 (0.8%)	0 (0.0%)	0 (0.0%)	3 (3.0%)	0.019
Others	3 (0.8%)	1 (1.5%)	9 (3.9%)	4 (4.0%)	0.802
Cardiovascular disease	34 (8.5%)	0 (0.0%)	16 (6.9%)	18 (18%)	<0.001
SF-36 MCS	51 (45–56)	49 (44–56)	51 (44–55)	52 (47–58)	0.048
Medications
β-blockers	10 (2.5%)	1 (1.5%)	4 (1.7%)	5 (5.1%)	0.220
Calcium-blockers	45 (11%)	2 (3.0%)	29 (12%)	14 (14%)	0.061
Thiazide diuretics	10 (2.5%)	0 (0.0%)	5 (2.1%)	5 (5.1%)	0.144
Laboratory blood test
eGFR, mL/min/1.73m^2	81 (72–89)	84 (76–94)	82 (74–92)	74 (66–85)	<0.001
Albumin, g/dL	4.6 (4.4–4.8)	4.7 (4.5–5.0)	4.6 (4.4–4.8)	4.4 (4.2–4.6)	<0.001
Total cholesterol, mg/dL	203 (179–224)	202 (174–219)	204 (179–225)	205 (180–228)	0.446
LDL-cholesterol, mg/dL	116 (95–132)	112 (90–125)	114 (96–132)	121 (99–137)	0.064
Triglyceride, mg/dL	97 (68–147)	99 (54–162)	100 (71–161)	90 (69–127)	0.172
Testosterone, ng/dL	605 (467–755)	584 (461–757)	610 (467–748)	622 (467–794)	0.738
Hypogonadism	14 (3.5%)	5 (7.6%)	5 (2.1%)	4 (4.0%)	0.085
Brinkman index	152 (0–440)	60 (0–240)	200 (0–455)	150 (0–600)	0.027
Current habitual drinking	268 (67%)	44 (67%)	158 (68%)	66 (67%)	0.972
Post-high school education	109 (27%)	27 (41%)	63 (27%)	19 (19%)	0.009
IIEF-5 score	17 (12–20)	23 (22–24)	17 (15–20)	8.0 (6.0–10)	<0.001

All data is presented as n (%) or median (interquartile range). ED: erectile dysfunction; DPP-4: dipeptidyl peptidase-4; SF-36 MCS: 36-Item Short Form Health Survey Mental Component Summary; eGFR: estimated glomerular filtration rate; LDL: low density lipoprotein; IIEF: International Index of Erectile Function.

Table 2. Characteristics of men on dialysis.

	All n = 42	Mild/moderate ED group n = 15	Severe ED group n = 27	p Value
Age, years	64 (55–66)	59 (54–65)	65 (56–66)	0.344
Body mass index, kg/m^2	23 (20–29)	24 (19–29)	23 (20–28)	0.753
Hypertension	37 (88%)	14 (93%)	23 (85%)	0.639
Dyslipidemia	30 (71%)	11 (73%)	19 (70%)	1.000
Diabetes mellitus	24 (57%)	9 (60%)	15 (56%)	0.780
Antidiabetic medications
Insulin	13 (30%)	4 (25%)	8 (30%)	1.000
α-Glucosidase inhibitors	3 (6.8%)	1 (6.3%)	2 (7.1%)	1.000
DPP-4 inhibitors	13 (30%)	6 (38%)	7 (25%)	0.345
None	3 (6.8%)	1 (6.3%)	2 (7.1%)	1.000
Cardiovascular disease	11 (26%)	2 (13%)	9 (33%)	0.273
Type of dialysis				1.000
PD	3 (7.1%)	1 (6.7%)	2 (7.4%)
HD	36 (86%)	13 (87%)	23 (85%)
Combination of PD and HD	3 (7.1%)	1 (6.7%)	2 (7.4%)
Duration of dialysis, months	64 (28–112)	51 (22–76)	84 (49–148)	0.028
Medications
β-blockers	17 (41%)	7 (47%)	10 (37%)	0.542
Calcium-blockers	13 (31%)	6 (40%)	7 (26%)	0.344
Thiazide diuretics	1 (2.4%)	0 (0.0%)	1 (3.7%)	1.000
Laboratory blood test
Albumin, g/dL	3.6 (3.4–3.8)	3.8 (3.5–4.0)	3.5 (3.1–3.8)	0.053
Phosphorus, mg/dL	4.6 (3.7–5.7)	5.1 (4.5–6.9)	4.0 (3.0–5.6)	0.016
Adjusted calcium, mg/dL	8.8 (8.3–9.2)	8.8 (8.2–9.2)	8.8 (8.3–9.2)	0.655
iPTH, pg/mL	116 (67–158)	147 (106–242)	95 (35–136)	0.004
Total cholesterol, mg/dL	145 (114–171)	145 (137–197)	131 (106–175)	0.429
LDL-cholesterol, mg/dL	67 (50–87)	50 (46–95)	68 (56–85)	0.253
Triglyceride, mg/dL	161 (109–177)	174 (164–178)	118 (92–220)	0.191
Testosterone, ng/dL	358 (222–509)	292 (221–436)	420 (222–511)	0.270
Hypogonadism	17 (41%)	8 (53%)	9 (33%)	0.206
Brinkman index	350 (4.5–633)	400 (0.0–700)	300 (6.0–611)	0.853
Current habitual drinking	10 (24%)	4 (27%)	6 (22%)	1.000
Post-high school education	7 (17%)	2 (13%)	5 (19%)	1.000
Having current sexual partner	26 (62%)	9 (60%)	17 (63%)	0.850
SHIM score	4.5 (1.0–10)	13 (9.0–18)	2.0 (1.0–4.0)	<0.001

All data is presented as n (%) or median (interquartile range).

ED: erectile dysfunction; DPP-4: dipeptidyl peptidase-4; PD: peritoneal dialysis; HD: hemodialysis; iPTH: intact parathyroid hormone; LDL: low density lipoprotein; SHIM: sexual health inventory for men.

Figure 3. Associations between urine and plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels and the severity of erectile dysfunction (ED). Correlations between urine 8-OHdG level and 5-Item International Index of Erectile Function (IIEF-5) score in community-dwelling men (A) and between plasma 8-OHdG level and Sexual Health Inventory for Men (SHIM) score in men on dialysis (B) were analyzed using Spearman’s rank correlation coefficient. Urine 8-OHdG levels were compared between the three groups using the Kruskal–Wallis test (C). Plasma 8-OHdG levels were compared between the two groups using the Mann–Whitney U test (E). The distribution of the ED degree in community-dwelling men (D) and the prevalence of severe ED in men on dialysis (F) were compared between men with lower and higher 8-OHdG levels using the chi-squared test.

Two correlation analyses and comparative analyses with box plots show no significant correlations and associations between 8-hydroxy-2'-deoxyguanosine levels and erectile dysfunction.

Table 3. Univariable and multivariable analyses for erectile dysfunction in community-dwelling men.

	Factor	p Value	Odds ratio	95% CI
Univariable analysis
Age	Continuous	<0.001	1.087	1.062–1.113
Body mass index	Continuous	0.748	0.986	0.907–1.073
Hypertension	Positive	<0.001	3.527	1.853–6.715
Dyslipidemia	Positive	0.075	1.754	0.945–3.257
Diabetes mellitus	Positive	0.045	4.384	1.033–18.61
Calcium-blockers	Taking	0.034	4.761	1.124–20.16
β-blockers	Taking	0.576	1.811	0.226–14.54
Brinkman index	Continuous	0.005	1.001	1.000–1.003
Hypogonadism	Positive	0.061	0.340	0.110–1.049
eGFR	Continuous	0.006	0.973	0.955–0.993
Urine 8-OHdG level	Continuous	0.934	1.005	0.884–1.144
Multivariable analysis
Age	Continuous	<0.001	1.088	1.056–1.121
Hypertension	Positive	0.303	1.506	0.691–3.283
Diabetes mellitus	Positive	0.691	1.378	0.284–6.682
Calcium-blockers	Taking	0.889	1.124	0.219–5.779
Brinkman index	Continuous	0.284	1.001	0.999–1.002
eGFR	Continuous	0.109	1.021	0.995–1.048
Urine 8-OHdG level	Continuous	0.353	0.930	0.798–1.084

CI: confidence interval; eGFR: estimated glomerular filtration rate; 8-OHdG: 8-hydroxy-2'-deoxyguanosine.

Table 4. Univariable analyses for moderate/severe erectile dysfunction in community-dwelling men with erectile dysfunction.

	Factor	p Value	Odds ratio	95% CI
Age	Continuous	<0.001	1.104	1.077–1.133
Body mass index	Continuous	0.964	0.998	0.925–1.078
Hypertension	Positive	0.004	2.019	1.252–3.254
Dyslipidemia	Positive	0.005	2.022	1.244–3.288
Diabetes mellitus	Positive	0.011	2.398	1.225–4.694
Calcium-blockers	Taking	0.674	1.159	0.583–2.301
β-blockers	Taking	0.102	3.045	0.800–11.59
Brinkman index	Continuous	0.966	1.000	0.999–1.000
Hypogonadism	Positive	0.399	1.920	0.505–7.306
eGFR	Continuous	<0.001	0.963	0.947–0.980
Urine 8-OHdG level	Continuous	0.604	1.030	0.922–1.149

CI: confidence interval; eGFR: estimated glomerular filtration rate; 8-OHdG: 8-hydroxy-2'-deoxyguanosine.

Table 5. Univariable analyses for severe erectile dysfunction in men on dialysis.

	Factor	p Value	Odds ratio	95% CI
Age	Continuous	0.429	1.027	0.961–1.099
Body mass index	Continuous	0.816	0.987	0.886–1.100
Hypertension	Positive	0.446	0.411	0.042–4.055
Dyslipidemia	Positive	0.839	0.864	0.211–3.542
Diabetes mellitus	Positive	0.780	0.833	0.231–3.003
Calcium-blockers	Taking	0.348	0.525	0.137–2.014
β-blockers	Taking	0.543	0.672	0.187–2.419
Brinkman index	Continuous	0.958	1.000	0.999–1.001
Hypogonadism	Positive	0.210	0.438	0.120–1.592
Albumin level	Continuous	0.053	0.164	0.026–1.025
Plasma 8-OHdG level	Continuous	0.498	0.967	0.876–1.066

CI: confidence interval; 8-OHdG: 8-hydroxy-2'-deoxyguanosine.