Table 1 shows the prevalence of PE and ED. There were 44 (2.3%) participants whose scores were (strongly) indicative of PE. There were eight (0.4%) participants with likely moderate ED, 98 (5.0%) participants with mild to moderate ED, and 546 (27.6%) participants with mild ED.
Table 1
Prevalence of PE and ED in the Sample of Urban Chinese Men
PE
|
n
|
%
|
ED
|
n
|
%
|
|
|
|
Moderate
|
8
|
0.4
|
Strongly Indicative
|
9
|
0.5
|
Mild to Moderate
|
95
|
5.0
|
Indicative
|
35
|
1.8
|
Mild
|
546
|
27.6
|
Low Probability
|
1932
|
97.8
|
No ED
|
1324
|
67.0
|
Note. PE = Premature Ejaculation; ED = Erectile Disorder. The Checklist for Early Ejaculation Symptoms (CHEES) was used to measure the ejaculatory function of the participants. A score ranging from 21 to 25 is strongly indicative of fulfilling the diagnostic criteria for PE. A score ranging from 17 to 20 is indicative of PE. A score ranging from 5 to 16 suggests a low probability of PE. Erectile function was measured by the International Index of Erectile Function-5 (IIEF-5). There are five categories of ED based on IIEF-5 scores: Severe (5–7), moderate (8–11), mild to moderate (12–16), mild (17–21), and no ED (22–25). |
Table 2 shows descriptive statistics and the results of correlation analyses between age, penile length, penile circumference, and ejaculatory and erectile function. First, there was a strong positive association between ejaculatory and erectile problems. Then, the result showed that older men reported less of both ejaculatory and erectile problems. Penile length (M = 14.49, SD = 2.22; Min = 5 cm, Max = 20 cm) and circumference (M = 15.85, SD = 5.42; Min = 4.7 cm, Max = 30 cm) were positively associated but the association was not particularly strong. Importantly, having a longer penis was associated with less of both ejaculatory and erectile problems while higher penile circumference was only associated with less ejaculatory problems.
Table 2
Correlations between Age, Penile Length, Penile Circumference, and Premature Ejaculation Problems and Erectile Function.
|
n
|
M
|
SD
|
Ejaculatory Problems
(CHEES)
|
Erectile Function
(IIEF-5)
|
Age
|
Penile Length
|
CHEES
|
1976
|
9.40
|
2.80
|
|
|
|
|
IIEF-5
|
1976
|
21.83
|
2.59
|
− .580**
|
|
|
|
Age
|
1976
|
31.54
|
5.27
|
− .076**
|
.056*
|
|
|
Penile Length
|
1085
|
14.49
|
2.22
|
− .201**
|
.117**
|
.008
|
|
Penile Circumference
|
663
|
15.85
|
5.42
|
− .222**
|
.061
|
.217**
|
.233**
|
Note. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems. Penile length means the penile length when the penis has a full erection. Penile circumference means the penile circumference when the penis has a full erection. *p < .05, **p < .01. |
Figure 2 shows the mean scores of CHEES and IIEF-5 in different age groups which indicated erectile and ejaculatory problems decreased and then increased with age.
Table 3 shows the result of the t-test analyses which indicated that the older group has less ejaculatory and erectile problems and a higher penile circumference than the younger group.
Table 4 shows the result of correlation analyses between age, penile length, penile circumference, and ejaculatory and erectile function in the younger and older groups separately. In the younger group, higher age was associated with less ejaculatory and erectile problems. Longer penile length was associated with less ejaculatory and erectile problems. In the older group, higher age was associated with more ejaculatory and erectile problems. Longer penile length was also associated with less ejaculatory and erectile problems. Higher penile circumference was associated with less ejaculatory problems.
We also investigated the stability of the associations between the sexual dysfunction variables and the other variables between the two age groups. The confidence intervals of correlations between age and CHEES, age and IIEF-5, as well as CHEES and penile circumference did not overlap. All the other correlations’ confidence intervals overlapped between the two age groups.
[Figure 2 Near Here]
Table 3
Descriptive Statistics by Age Groups
|
Group
|
n
|
M
|
SD
|
t
|
p
|
CHEES
|
Younger
|
947
|
9.71
|
2.82
|
5.159
|
.001
|
|
Older
|
1029
|
9.06
|
2.74
|
|
|
IIEF-5
Penile Length
Penile Circumference
|
Younger
Older
Younger
Older
Younger
Older
|
947
1029
502
583
351
312
|
21.60
22.09
14.39
14.61
14.29
17.23
|
2.70
2.44
2.19
2.26
4.35
5.89
|
-4.281
-1.652
-7.238
|
.001
.099
.001
|
Note. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems. Penile length means the penile length when the penis has a full erection. Penile circumference means the penile circumference when the penis has a full erection. The younger and older groups were split by the median age of 31. Participants aged 31 or younger were defined as younger. Participants older than 31 were older. |
Table 4
Correlations between Age, Penile Length, Penile Girth, Ejaculatory Problem and Erectile Function in Younger and Older Group.
|
|
Ejaculatory Problems
(CHEES)
|
Erectile Function
(IIEF-5)
|
Age
|
Penile Length
|
Penile Girth
|
|
|
|
n = 947
|
n = 947
|
n = 502
|
n = 351
|
CHEES
|
|
-
|
− .572**
|
.164**
|
− .270**
|
− .312**
|
IIEF-5
|
n = 1029
|
− .578**
|
-
|
− .169**
|
.130**
|
.099
|
Age
|
n = 1029
|
− .135**
|
.113**
|
-
|
− .114*
|
.001
|
Penile Length
|
n = 583
|
− .131**
|
.101*
|
.016
|
-
|
.229**
|
Penile Girth
|
n = 312
|
− .004
|
− .008
|
.018
|
.184**
|
-
|
Note. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems. Penile length means the penile length when the penis has a full erection. Penile girth means the penile circumference when the penis has a full erection. Below diagonals are the correlations in the younger group. Above diagonals are the correlations in the older group. *p < .05, **p < .01. |
Considering the complex effects of age on the relationship between penis size and sexual function, we conducted linear regression analyses between penile size and sexual dysfunction controlling for age. Table 5 shows the result of linear regression analyses between penile length, penile circumference and ejaculatory function before (R2 = .093, F(2,637) = 33.751, p < .001) and after (R2 = .101, F(3,636) = 25.023, p < .001) controlling for age, also for erectile function before (R2 = .029, F(2,637) = 10.65, p < .001) and after (R2 = .032, F(3,636) = 7.943, p < .001) controlling for age. The results showed that longer penile length was associated with less ejaculatory and erectile problems after controlling age. Higher penile circumference was only associated with less ejaculatory problems after controlling age.
Table 5
Linear Regression Analyses between Penile Length, Penile Girth and Ejaculatory Problems and Erectile Function before and after Controlling for Age.
Dependent
Variable
|
Independent
Variable
|
Controlled For
|
B
|
β
|
t
|
p
|
CHEES
|
|
|
|
|
|
|
|
Penile Length
|
-
Age
|
− .264
− .263
|
− .209
− .208
|
-5.404
-5.4
|
0
0
|
|
Penile Girth
|
-
Age
|
− .09
− .079
|
− .184
− .162
|
-4.756
-4.109
|
0
0
|
IIEF-5
|
|
|
|
|
|
|
|
Penile Length
|
-
Age
|
.198
.197
|
.173
.172
|
4.304
4.291
|
0
0
|
|
Penile Girth
|
-
Age
|
.011
.005
|
.025
.011
|
0.615
0.267
|
.538
.789
|
Note. Penile length means the penile length when the penis has a full erection. Penile girth means the penile circumference when the penis has a full erection. The upper rows present the results of regression analyses before controlling for age. The lower rows present the results of regression analyses after controlling for age. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems. |
Table 6 shows the descriptive of the circumcised and uncircumcised groups and the result of t-test analyses. There were 737 (37.3%) participants who had been circumcised and 1239 (62.7%) participants who had not. The t-tests indicated that the circumcised group had less ejaculatory (t(1974) = 8.886, p < .001) and erectile (t(1974) = -4.890, p < .001) problems than the uncircumcised group.
Table 6
Descriptive of the Circumcised and Not Circumcised Group
Group
|
n
|
%
|
CHEES
M
|
SD
|
IIEF-5
M
|
SD
|
No-Circumcised
|
1239
|
62.7
|
9.819
|
2.804
|
21.608
|
2.637
|
Circumcised
|
737
|
37.3
|
8.684
|
2.648
|
22.194
|
2.473
|
Note. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems. |
Table 7 shows the descriptive of the groups with different degrees of foreskin covering the glans penis without an erection and with a full erection, and the association between different degrees of foreskin coverage and ejaculatory and erectile problems in uncircumcised participants. Participants who reported that their foreskin covered 100%, 75%, 50%, 25%, 0% of their glans penis when their penis was not erect were 116 (9.4%), 365 (29.5%), 353 (28.5%), 205 (16.5%), 200 (16.1%), respectively. Participants who reported that their foreskin covered 100%, 75%, 50%, 25%, 0% of their glans penis when their penis was fully erect were 6 (0.5%), 41 (3.3%), 75 (6.1%), 124 (10.0%), 993 (80.1%), respectively.
Less foreskin covering the glans penis both without an erection and with a full erection was associated with less of both ejaculatory and erectile problems. There were significant differences between the groups in ejaculatory (F(4,1234) = 10.252, p < .001) and erectile (F(4,1234) = 6.714, p < .001) problems without an erection. The result of the post hoc tests indicated that participants with glans covering 100% of the foreskin without an erection had more ejaculatory and erectile problems than the other groups. There were no significant differences between the other groups. There were also significant differences between the different degree groups of foreskin covering the glans in ejaculatory (F(4,1234) = 14.721, p < .001) and erectile (F(4,1234) = 22.733, p < .001) problems with a full erection. The result of the post hoc test indicated that participants with glans covered 0% by the foreskin with a full erection had less ejaculatory and erectile problems than the other group. There were no significant differences between the other groups. Interestingly, the degree of foreskin covering the glans penis without an erection (r = .029; r = .041) and with a full erection (r = .052; r = .006) was not associated with either penile length or circumference.
Table 7
Descriptive of Groups with Different Degrees of Foreskin Covering the Glans Penis Without an Erection and With a Full Erection in Uncircumcised Group
|
Group
|
n
|
%
|
CHEES
M
|
SD
|
r
|
IIEF-5
M
|
SD
|
r
|
No Erection
|
|
|
|
|
|
− .078**
|
|
|
.147**
|
|
100%
|
116
|
9.4
|
11.371
|
3.340
|
|
20.586
|
3.163
|
|
|
75%
|
365
|
29.5
|
9.666
|
2.642
|
|
21.471
|
2.516
|
|
|
50%
|
353
|
28.5
|
9.586
|
2.547
|
|
21.674
|
2.460
|
|
|
25%
|
205
|
16.5
|
9.781
|
2.718
|
|
21.893
|
2.700
|
|
|
0%
|
200
|
16.1
|
9.65
|
3.011
|
|
22.04
|
2.610
|
|
Full Erection
|
|
|
|
|
|
− .195**
|
|
|
.225**
|
|
100%
|
6
|
0.5
|
9.167
|
1.602
|
|
20.833
|
2.317
|
|
|
75%
|
41
|
3.3
|
11.902
|
3.680
|
|
19.512
|
3.809
|
|
|
50%
|
75
|
6.1
|
11.08
|
3.083
|
|
20.6
|
2.666
|
|
|
25%
|
124
|
10.0
|
10.573
|
2.889
|
|
20.274
|
3.309
|
|
|
0%
|
993
|
80.1
|
9.548
|
2.657
|
|
21.942
|
2.363
|
|
Note. Higher values of CHEES suggest more ejaculatory problems. Higher values of IIEF-5 suggest less erectile problems.100% means the foreskin completely covers the glans, and 0% means the foreskin does not cover the glans at all. The smaller the ratio, the less the foreskin covers the glans. **p < .01. |