Table 1 Baseline characteristics of volunteers by UIC group.
UIC group
|
SD
|
MOD
|
MID
|
OREF
|
MTA
|
PE
|
P
|
Total
|
N
|
10
|
59
|
205
|
405
|
236
|
174
|
|
1089
|
Age, y
|
27.10
|
27.02
|
27.57
|
27.53
|
27.80
|
26.90
|
|
|
mean±SD
|
1.08
|
0.42
|
0.28
|
0.20
|
0.26
|
0.27
|
|
|
Age, n(%)
|
|
|
|
|
|
0.389
|
<24
|
3(30.0)
|
11(18.6)
|
44(21.5)
|
93(23.0)
|
51(21.6)
|
46(26.4)
|
|
248(22.8)
|
25-29
|
4(40.0)
|
36(61.0)
|
110(53.7)
|
211(52.1)
|
110(46.6)
|
94(54.0)
|
|
565(51.9)
|
30-35
|
3(30.0)
|
9(15.3)
|
36(17.6)
|
77(19.0)
|
61(25.8)
|
29(16.7)
|
|
215(19.7)
|
>35
|
0(0)
|
3(5.1)
|
15(7.3)
|
24(5.9)
|
14(5.9)
|
5(2.9)
|
|
61(5.6)
|
BMI, kg/m2
|
21.68
|
22.93
|
23.22
|
22.95
|
23.23
|
22.79
|
|
|
mean±SD
|
0.73
|
0.33
|
0.19
|
0.13
|
0.17
|
0.17
|
|
|
BMI n(%)
|
|
|
|
|
|
|
0.895
|
<25
|
9(90.0)
|
48(81.4)
|
162(79.0)
|
329(81.2)
|
189(80.1)
|
146(83.9)
|
|
883(81.1)
|
25-30
|
1(10.0)
|
11(18.6)
|
39(19.0)
|
71(17.5)
|
42(17.8)
|
28(16.1)
|
|
192(17.6)
|
30-35
|
0(0)
|
0(0)
|
4(2.0)
|
4(1.0)
|
5(2.1)
|
0(0)
|
|
13(1.2)
|
>35
|
0(0)
|
0(0)
|
0(0)
|
1(0.2)
|
0(0)
|
0(0)
|
|
1(0.1)
|
Education level, n(%)
|
|
|
|
|
|
0.124
|
Under senior school
|
0(0)
|
0(0)
|
2(1.0)
|
10(2.5)
|
10(4.2)
|
8(4.6)
|
|
30(2.8)
|
Senior school
and above
|
10(100.0)
|
59(100.0)
|
203(99.0)
|
395(97.5)
|
226(95.8)
|
166(95.4)
|
|
1059(97.2)
|
Residence, n(%)
|
|
|
|
|
|
|
0.007
|
Urban
|
5(50.0)
|
19(32.2)
|
66(32.2)
|
148(36.5)
|
107(45.3)
|
67(38.5)
|
|
412(37.8)
|
Rural
|
4(40.0)
|
23(39.0)
|
104(50.7)
|
200(49.4)
|
107(45.3)
|
88(50.6)
|
|
526(48.3)
|
Fringe area
|
1(10.0)
|
17(28.8)
|
35(21.1)
|
57(14.1)
|
22(9.3)
|
19(10.9)
|
|
151(13.9)
|
Smoking status, n(%)
|
|
|
|
|
|
0.334
|
Never smokers
|
6(60.0)
|
35(59.3)
|
126(61.5)
|
274(67.7)
|
156(66.1)
|
103(59.2)
|
|
700(64.3)
|
Current smokers
|
4(40.0)
|
24(40.7)
|
79(38.5)
|
131(32.3)
|
80(33.9)
|
71(40.8)
|
|
389(35.7)
|
Alcohol status, n(%)
|
|
|
|
|
|
0.058
|
Never alcohol
|
3(30.0)
|
24(40.7)
|
82(40.0)
|
211(52.1)
|
110(46.6)
|
78(44.8)
|
|
508(46.6)
|
Alcohol
|
7(70.0)
|
35(59.3)
|
123(60.0)
|
194(47.9)
|
126(53.4)
|
96(55.2)
|
|
581(53.4)
|
UIC group: SD: severe deficiency(﹤20 ug/L), MOD: moderate deficiency(≥20~﹤50 ug/L), MID: mild deficiency(≥50~﹤100 ug/L), OREF: optimal(≥100~﹤200 ug/L), MTA: more than adequate(≥200~﹤300 ug/L), PE: Possible excess (≥300ug/L)
Table 2 Baseline characteristics of reproductive and semen parameters by UIC group.
UIC group
|
SD
|
MOD
|
MID
|
OREF
|
MTA
|
PE
|
P
|
Total
|
Pregnant history, n(%)
|
|
|
|
|
0.759
|
|
≤2
|
10(100)
|
56(94.9)
|
191(93.2)
|
379(93.6)
|
219(92.8)
|
158(90.8)
|
|
1013(93.0)
|
>3
|
0(0)
|
3(5.1)
|
14(6.8)
|
26(6.4)
|
17(7.2)
|
16(9.2)
|
|
76(7.0)
|
Birth history, y, n(%)
|
|
|
|
|
0.238
|
|
<1
|
8(80.0)
|
48(21.4)
|
162(79.0)
|
319(78.8)
|
169(71.6)
|
140(80.5)
|
|
846(78.7)
|
≥1
|
2(20.0)
|
11(18.6)
|
43(21.0)
|
86(21.2)
|
67(28.4)
|
34(19.5)
|
|
243(22.3)
|
TTP, month , n(%)
|
|
|
|
|
0.000
|
|
<12
|
7(70)
|
46(78.0)
|
168(82.0)
|
395(97.5)
|
230(97.5)
|
149(85.6)
|
|
995(91.4)
|
≥12
|
3(30)
|
13(22.0)
|
37(18.0)
|
10(2.5)
|
6(2.5)
|
25(14.4)
|
|
94(8.6)
|
Abstinence period, day, n(%)
|
|
|
|
|
0.412
|
|
2-3
|
1(10.0)
|
15(25.4)
|
36(17.6)
|
68(16.8)
|
44(18.6)
|
19(10.9)
|
|
183(16.8)
|
3-5
|
7(70.0)
|
31(52.5)
|
131(63.9)
|
254(62.7)
|
147(62.3)
|
123(70.7)
|
|
693(63.6)
|
5-7
|
2(20.0)
|
13(22.1)
|
38(18.5)
|
83(20.5)
|
45(19.1)
|
32(18.4)
|
|
213(19.6)
|
Media(IQR)
|
4(3,4.625)
|
4(2.5,5.0)
|
4(3,5)
|
4(3,5)
|
4(3,5)
|
4(3,5)
|
|
|
Semen volume,ml, n(%)
|
|
|
|
|
0.7
|
|
<1.5
|
1(10.0)
|
3(5.1)
|
11(5.4)
|
29(7.2)
|
14(5.9)
|
7(4.0)
|
|
65(6.0)
|
≥1.5
|
9(90.0)
|
56(94.9)
|
194(94.6)
|
376(92.8)
|
222(94.1)
|
167(96.1)
|
|
1024(94.0)
|
Media(IQR)
|
2.65(2.38,3.75)
|
3.00(2.50,3.60)
|
2.80(2.25,2.85)
|
2.7(2.1,3.5)
|
2.9(2.2,3.79)
|
2.85(2.3,3.83)
|
|
|
Semen pH
|
|
|
|
|
|
0.026
|
|
≤7.2
|
4(40.0)
|
34(57.6)
|
104(50.7)
|
202(49.9)
|
101(42.8)
|
66(37.9)
|
|
511(46.9)
|
>7.2
|
6(60.0)
|
25(43.4)
|
101(49.3)
|
203(50.1)
|
135(57.2)
|
108(62.1)
|
|
578(53.1)
|
Sperm concentration, ×106/ml, n(%)
|
|
|
|
0.000
|
|
<15
|
1(10.0)
|
5(8.5)
|
18(8.8)
|
2(0.5)
|
3(1.3)
|
17(9.8)
|
|
46(4.2)
|
≥15
|
9(90.0)
|
54(91.5)
|
187(91.2)
|
403(99.5)
|
233(98.7)
|
157(90.2)
|
|
1043(95.8)
|
Media(IQR)
|
35.75
(20.88,47.25)
|
36.5(24,46)
|
42(28.25,54)
|
62(44,90)
|
59(41,84.75)
|
44(28.75,59.5)
|
|
|
Total sperm count, ×106, n(%)
|
|
|
|
0.000
|
|
<39
|
2(20.0)
|
6(10.2)
|
21(10.2)
|
5(1.2)
|
4(1.7)
|
17(9.8)
|
|
55(5.1)
|
≥39
|
8(80.0)
|
53(89.8)
|
184(89.8)
|
400(98.8)
|
232(98.3)
|
157(90.2)
|
|
1034(94.9)
|
Media(IQR)
|
112.88
(42.08,187.88)
|
107.20
(60.00,164.15)
|
120.4
(73,183.6)
|
165.2
(107.2,264.8)
|
178.35
(102.13,244.85)
|
122.25
(83.11,191.29)
|
|
|
Total motility (%)
|
|
|
|
|
|
0.570
|
|
<40
|
0(0)
|
10(16.9)
|
23(11.2)
|
53(13.1)
|
36(15.3)
|
22(12.6)
|
|
144(13.2)
|
≥40
|
10(100)
|
49(83.1)
|
182(88.8)
|
352(86.9)
|
200(84.7)
|
152(87.4)
|
|
945(86.8)
|
Media(IQR)
|
49(42.25,57.50)
|
50(43,60)
|
52(45,60)
|
51(43,62.5)
|
52(42,60)
|
50(44,58)
|
|
|
Progressive motility(PR) (%)
|
|
|
|
|
0.948
|
|
<32
|
1(10.0)
|
10(16.9)
|
30(14.6)
|
68(16.8)
|
42(17.8)
|
28(16.1)
|
|
179(16.4)
|
≥32
|
9(90.0)
|
49(83.1)
|
175(85.4)
|
337(83.2)
|
194(82.2)
|
146(83.9)
|
|
910(83.6)
|
None progressive motility(NP) (%)
|
|
|
|
0.104
|
|
<1
|
1(10.0)
|
3(5.1)
|
4(2.0)
|
6(1.5)
|
2(0.8)
|
3(1.7)
|
|
19(1.7)
|
≥1
|
9(90.0)
|
56(94.9)
|
201(98.0)
|
399(98.5)
|
234(99.2)
|
171(98.3)
|
|
1070(98.3)
|
UIC group: SD: severe deficiency(﹤20 ug/L), MOD: moderate deficiency(≥20~﹤50 ug/L), MID: mild deficiency(≥50~﹤100 ug/L), OREF: optimal(≥100~﹤200 ug/L), MTA: more than adequate(≥200~﹤300 ug/L), PE: possible excess(≥300ug/L)
Table 3 Association between semen quality parameters and higher UIC (continuous outcomes)
Category
|
Volume (ml)
|
Total Motility
|
Semen pH
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
OREF
|
2.7(2.1,3.5)
|
51(43,62.5)
|
7.3(7.2,7.5)
|
44.57(36.12,53.50)
|
6.57(3.97,9.84)
|
49.00(37.55,57.03)
|
62(44,90)
|
165.2(107.2,264.8)
|
3.86(2.0,5.0)
|
MTA
|
2.9(2.2,3.8)
|
52(42,60)
|
7.3(7.2,7.5)
|
44.86(35.74,52.50)
|
6.73(4.09,9.27)
|
48.01(40.08,58.08)
|
59(41,,84.75)
|
178.35(102.13,244.85)
|
4.32(2.0,6.0)
|
PE
|
2.85(2.3,3.83)
|
50(44,58)
|
7.3(7.2,7.6)
|
44.19(36.47,51.10)
|
6.21(3.67,9.64)
|
50(41.89,55.97)
|
44(28.75,59.5)
|
122.25(83.11,191,29)
|
6.56(2.0,9.0)
|
P-model 1
|
0.148
|
0.740
|
|
0.704
|
|
0.741
|
0.000
|
0.000
|
0.000
|
P-model 2
|
0.201
|
0.462
|
|
0.101
|
|
0.462
|
0.000
|
0.000
|
0.000
|
P value for trend test based on linear models. Linear regression was performed to analyze semen parameters. Model 1 was unadjusted and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence. OREF: optimal(≥100~﹤200 ug/L), MTA: more than adequate(≥200~﹤300 ug/L), PE: possible excess(≥300ug/L)
Table 4 Association between abnormal semen quality parameters and higher UIC continuous outcomes (%)
Category
|
Semen volume
|
Total Motility
|
Semen pH
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
|
≤1.5 ml
|
<40
|
≤7.2
|
<32
|
<1
|
<22
|
<15×106/ml
|
<39×106
|
<12 months
|
OREF
|
29(7.16)
|
53(13.09)
|
202(49.87)
|
68(16.79)
|
6(1.48)
|
2(0.49)
|
2(0.49)
|
5(1.23)
|
10(2.47)
|
MTA
|
14(5.93)
|
36(15.25)
|
101(42.80)
|
42(17.80)
|
2(0.85)
|
2(0.85)
|
3(1.27)
|
4(1.69)
|
6(2.54)
|
PE
|
7(4.02)
|
22(12.64)
|
66(37.93)
|
28(16.09)
|
3(1.72)
|
0(0)
|
17(9.77)
|
17(9.77)
|
25(14.39)
|
P-trend model 1
|
0.329
|
0.597
|
|
0.570
|
0.713
|
0.322
|
0.000
|
0.000
|
0.000
|
P-trend model 2
|
0.361
|
0.646
|
0.030
|
0.497
|
0.645
|
0.256
|
0.000
|
0.000
|
0.000
|
Semen was dichotomized as normal or abnormal according to WHO standard
P value for trend test based on linear models. Linear regression was performed to analyze semen parameters. Model 1 was unadjusted model and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence. OREF: optimal(≥100~﹤200 ug/L), MTA: more than adequate(≥200~﹤300 ug/L), PE: possible excess(≥300ug/L)
Table 5. The association between higher UIC and the likelihood of having abnormal semen parameters by category outcomes
Category
|
|
volume
|
Total Motility
|
Semen pH
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
|
|
≤1.5 ml
|
<40
|
≤7.2
|
<32
|
<1
|
<22
|
<15×106/ml
|
<39×106
|
<12 months
|
OREF
|
|
reference
|
reference
|
|
reference
|
reference
|
reference
|
reference
|
reference
|
reference
|
MTA
|
CI
|
0.82
|
1.20
|
0.75
|
1.07
|
0.57
|
1.72
|
2.59
|
1.38
|
1.03
|
model 1
|
95CI
|
0.42-1.58
|
0.76-1.89
|
0.54-1.04
|
0.70-1.64
|
0.117-2.84
|
0.24-12.31
|
0.43-15.64
|
0.37-5.19
|
0.37-2.87
|
PE
|
CI
|
0.54
|
0.96
|
0.61
|
0.95
|
1.17
|
|
21.82
|
8.66
|
6.63
|
model 2
|
95CI
|
0.23-1.27
|
0.57-1.64
|
0.43-0.88
|
0.59-1.54
|
0.29-4.72
|
|
4.98-95.53
|
3.14-23.88
|
3.11-14.13
|
MTA
model 2
|
CI
|
0.83
|
1.244
|
0.75
|
1.06
|
0.57
|
1.37
|
2.33
|
1.45
|
0.99
|
95CI
|
0.42-1.62
|
0.78-1.98
|
0.54-1.05
|
0.69-1.63
|
0.11-2.90
|
0.18-10.25
|
0.38-14.22
|
0.38-5.54
|
0.35-2.82
|
PE
model 2
|
CI
|
0.56
|
0.99
|
0.64
|
0.92
|
1.02
|
|
18.53
|
8.64
|
7.49
|
95CI
|
0.24-1.32
|
0.58-1.71
|
0.44-0.92
|
0.56-1.50
|
0.24-4.25
|
|
4.20-81.73
|
3.07-24.34
|
3.34-16.80
|
Semen parameters was dichotomized per WHO standard. Multivariable logistic regression was performed for estimating ORs. Model 1 was cruded model and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence. OREF: optimal(≥100~﹤200 ug/L), MTA: more than adequate(≥200~﹤300 ug/L), PE: possible excess(≥300ug/L)
Table 6 Association between semen quality parameters and deficient UIC (continuous outcomes)
Category
|
Volume (ml)
|
Total Motility
|
Semen pH
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
SD
|
2.65(2.375,3.75)
|
49.00(42.25,57)
|
7.45(7.00,7.70)
|
45.84(37.44,54.66)
|
4.15(1.86,8.80)
|
51.01(42.44,57.77)
|
30.75(25.88,47.25)
|
112.88(42.08,87.88)
|
8.4(2.75,17.5)
|
MOD
|
3.0(2.5,3.6)
|
50.00(43,60)
|
7.2(7.2,7.6)
|
44.78(34.57,51.90)
|
7.19(4.24,10.28)
|
50(40,57.07)
|
36.50(24.00,46.00)
|
107.20(60,164.15)
|
7.65(3.0,11.0)
|
MID
|
2.80(2.25,3.85)
|
52(45,60)
|
7.2(7.2,7.55)
|
44.31(36.59,52.56)
|
6.52(4.29,10.04)
|
47.93(39.93,55.03)
|
42(28.25,54)
|
120.4(73,183.6)
|
7.52(3.0,10.0)
|
OREF
|
2.7(2.1,3.5)
|
51(43,62.5)
|
7.3(7.2,7.5)
|
44.57(36.12,53.50)
|
6.57(3.97,9.84)
|
49.00(37.55,57.03)
|
62(44,90)
|
165.2(107.2,264.8)
|
3.86(2.0,5.0)
|
P-Trend
model 1
|
0.105
|
0.790
|
0.963
|
0.749
|
0.859
|
0.792
|
0.000
|
0.000
|
0.000
|
P-Trend model 2
|
0.598
|
0.448
|
0.22
|
0.219
|
0.088
|
0.445
|
0.000
|
0.000
|
0.000
|
P value for trend test based on linear models. Linear regression was performed to analyze semen parameters. Model 1 was unadjusted and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence. SD: severe deficiency(﹤20 ug/L), MOD: moderate deficiency(≥20~﹤50 ug/L), MID: mild deficiency(≥50~﹤100 ug/L), OREF: optimal(≥100~﹤200 ug/L).
Table 7 Association between abnormal semen quality parameters and deficient UIC (continuous outcomes %)
Category
|
Semen volume
|
Semen pH
|
Total Motility
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
|
≤1.5 ml
|
<40
|
≤7.2
|
<32
|
<1
|
<22
|
<15×106/ml
|
<39×106
|
<12 months
|
SD
|
1(10)
|
4(40)
|
0(0)
|
1(10)
|
1(10)
|
0(0)
|
1(10)
|
2(20)
|
3(30)
|
MOD
|
3(5.08)
|
34(57.62)
|
10(16.94)
|
10(16.94)
|
3(5.08)
|
1(1.69)
|
5(8.47)
|
6(10.16)
|
13(22.03)
|
MID
|
11(5.36)
|
104(50.73)
|
23(11.22)
|
30(14.63)
|
4(1.95)
|
1(0.49)
|
18(8.78)
|
21(10.24)
|
37(18.05)
|
OREF
|
29(7.16)
|
202(49.87)
|
53(13.09)
|
68(16.79)
|
6(1.48)
|
2(0.49)
|
2(0.49)
|
5(1.23)
|
10(2.47)
|
P-trend model 1
|
0.830
|
0.440
|
0.996
|
0.816
|
0.989
|
0.349
|
0.000
|
0.000
|
0.000
|
P-trend model 2
|
0.735
|
0.258
|
0.979
|
0.623
|
0.065
|
0.349
|
0.000
|
0.000
|
0.000
|
Semen was dichotomized as normal or abnormal according to WHO standard.
P value for trend test based on linear models. Linear regression was performed to analyze semen parameters. Model 1 was unadjusted model and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence.
SD: severe deficiency(﹤20 ug/L), MOD: moderate deficiency(≥20~﹤50 ug/L), MID: mild deficiency(≥50~﹤100 ug/L), OREF: optimal(≥100~﹤200 ug/L),
Table 8, the association between deficient UIC and the likelihood of having abnormal semen parameters by category outcomes
Category
|
|
volume
|
Total Motility
|
Semen pH
|
PR
|
NP
|
IM
|
Semen concentration
|
Total sperm count
|
TTP
|
|
|
≤1.5 ml
|
<40
|
≤7.2
|
<32
|
<1
|
<22
|
<15×106/ml
|
<39×106
|
<12 months
|
SD
|
CI
|
1.44
|
0
|
0.67
|
0.55
|
7.39
|
0
|
22.84
|
20.00
|
16.93
|
model 1
|
95CI
|
0.18-11.77
|
|
0.19-2.41
|
0.07-4.42
|
0.80-67.88
|
|
1.86-269.95
|
3.36-11.-8.94
|
3.81-75.19
|
MOD
|
CI
|
0.70
|
1.36
|
1.37
|
1.016
|
3.56
|
3.47
|
18.66
|
9.06
|
11.63
|
model 1
|
95CI
|
0.21-2.36
|
0.65-2.84
|
0.79-2.37
|
0.49-2.10
|
0.87-14.65
|
0.31-38.92
|
3.35-98.54
|
2.67-30.70
|
4.63-26.89
|
MID
|
CI
|
0.74
|
0.84
|
1.04
|
0.85
|
1.32
|
0.99
|
19.40
|
9.13
|
8.67
|
model 1
|
95CI
|
0.36-1.50
|
0.50-1.41
|
0.74-1.45
|
0.53-1.36
|
0.37-4.74
|
0.09-10.96
|
4.46-84.45
|
3.39-24.59
|
4.23-17.90
|
SD
|
CI
|
1.14
|
0
|
0.69
|
0.47
|
9.15
|
0
|
27.35
|
24.555
|
19.40
|
model 2
|
95CI
|
0.13-9.77
|
|
0.19-2.51
|
0.06-3.88
|
0.88-95.56
|
|
2.12-353.62
|
3.85-156.38
|
4.17-90.20
|
MOD
|
CI
|
0.73
|
1.34
|
1.45
|
0.95
|
3.28
|
3.65
|
12.97
|
7.11
|
10.52
|
model 2
|
95CI
|
0.21-2.52
|
0.63-2.82
|
0.84-2.58
|
0.45-1.98
|
0.77-14.05
|
0.32-42.28
|
2.34-71.41
|
2.03-24.91
|
4.29-25.78
|
MID
|
CI
|
0.75
|
0.85
|
1.07
|
0.84
|
1.37
|
1.02
|
17.00
|
8.68
|
8.44
|
model 2
|
95CI
|
0.37-1.55
|
0.50-1.44
|
0.76-1.50
|
0.52-1.35
|
0.38-4.99
|
0.09-11.57
|
3.85-75.07
|
3.18-23.70
|
4.07-17.49
|
OREF
|
|
reference
|
reference
|
reference
|
reference
|
reference
|
reference
|
reference
|
reference
|
reference
|
Semen parameters was dichotomized per WHO standard. Multivariable logistic regression was performed for estimating ORs. Model 1 was cruded model and model 2 adjusted for age, education level, smoke status, alcohol status, BMI and residence. SD: severe deficiency(﹤20 ug/L), MOD: moderate deficiency(≥20~﹤50 ug/L), MID: mild deficiency(≥50~﹤100 ug/L), OREF: optimal(≥100~﹤200 ug/L),