Table 2.
Descriptive statistics based on the smoking status.
| Primary infertile men(N=1430) | Secondary infertile men(N=508) | |||||||
|---|---|---|---|---|---|---|---|---|
| non-smokers (n=817) |
Moderate smokers(n=405) | Heavy smokers(n=208) | P | non-smokers(n=250) | Moderate smokers(n=163) | Heavy smokers(n=95) | P | |
| Age(year),mean ± s.d. | 29.8 ± 3.9 | 29.2 ± 4.0 | 30.1 ± 4.8 | 0.04 | 32.4 ± 5.3 | 31.5 ± 5.3 | 33.7 ± 5.2 | 0.001 |
| <40,n(%) | 97.4(795) | 98.3(398) | 96.1(200) | 0.28 | 89.6(224) | 92.0(150) | 84.2(80) | 0.14 |
| ≥40,n(%) | 1.5(21) | 1.7(7) | 3.8(8) | 10.4(26) | 8.0(13) | 15.8(15) | ||
| BMI(kg/m^2),mean ± s.d. | 24.8 ± 3.7 | 25.3 ± 4.4 | 25.1 ± 4.4 | 0.24 | 24.6 ± 3.5 | 25.0 ± 4.4 | 25.7 ± 5.0 | 0.39 |
| <24,n(%) | 43.0(351) | 49.4(165) | 42.8(89) | 0.74 | 42.8(107) | 44.8(73) | 36.8(35) | 0.45 |
| ≥24,n(%) | 57.0(465) | 50.6(240) | 57.2(119) | 57.2(143) | 55.2(90) | 63.2(60) | ||
| Duration of infertility,n(%) | 0.11 | 0.18 | ||||||
| ≤1 year | 76.2(622) | 76.8(311) | 71.6(149) | 72.4(181) | 72.4(118) | 72.6(69) | ||
| >1 year,<3 year | 14.4(118) | 11.9(48) | 13.0(27) | 13.2(33) | 16.0(26) | 7.4(7) | ||
| ≥3 year | 9.4(77) | 11.3(46) | 15.4(32) | 14.4(36) | 11.6(19) | 20.0(19) | ||
| Frequency of night snack intake,n(%) | 0.0001 | <0.0001 | ||||||
| 0/week | 33.5(274) | 25.2(102) | 21.2(44) | 50.0(125) | 28.2(46) | 24.2(23) | ||
| 1-3/week | 63.8(521) | 70.4(285) | 72.1(150) | 47.6(119) | 68.7(112) | 70.5(67) | ||
| >3/week | 2.7(22) | 4.4(18) | 6.7(14) | 2.4(6) | 3.1(5) | 5.3(5) | ||
| Dietary habits,n(%) | <0.0001 | <0.0001 | ||||||
| Regular diet(three meals per day) | 72.3(591) | 59.5(241) | 47.1(98) | 80.4(201) | 60.7(99) | 46.3(44) | ||
| Irregular diet | 27.7(226) | 40.5(164) | 52.9(110) | 19.6(49) | 39.3(64) | 53.7(51) | ||
| Work time, n(%) | 0.06 | 0.89 | ||||||
| <8(h/d) | 32.3(264) | 34.3(139) | 34.6(72) | 38.0(95) | 38.0(62) | 36.8(35) | ||
| 8-10(h/d) | 52.3(427) | 46.1(187) | 43.8(91) | 44.0(110) | 40.5(66) | 45.3(43) | ||
| >10(h/d) | 15.4(126) | 19.5(79) | 21.6(45) | 18.0(45) | 21.5(35) | 17.9(17) | ||
| Sleep time, n(%) | 0.36 | 0.06 | ||||||
| ≤8(h/d) | 76.0(621) | 72.3(293) | 73.6(153) | 75.6(189) | 65.0(106) | 69.5(66) | ||
| >8(h/d) | 24.0(196) | 27.7(112) | 26.4(55) | 24.4(61) | 35.0(57) | 30.5(29) | ||
| Semen parameters | ||||||||
| Semen volume(ml),median(Q1,Q3) | 3.3(2.3,4.4) | 3.0(2.2,4.1) | 2.8(2.0,4.0) | 0.01 | 3.2(2.2,4.5) | 3.0(2.1,4.1) | 2.8(1.8,3.7) | 0.008 |
| Semen volume<1.5(ml),n(%) | 7.6(62) | 8.6(35) | 12.0(25) | 0.67 | 6.8(17) | 9.2(15) | 12.6(12) | 0.22 |
| Sperm concentration(×10^6/ml), median(Q1,Q3) |
68.6(36.0,121.7) | 60.7(31.4, 101.8) | 59.2(28.8,116.2) | 0.01 | 77.9(45.6,129.4) | 69.2(34.2, 120.8) | 72.3(43.2,127.8) | 0.18 |
| Sperm concentration<15×10^6/ml, n(%) |
7.7(63) | 12.1(49) | 13.9(29) | 0.005 | 5.6(14) | 8.6(14) | 10.5(10) | 0.24 |
| Progressive motility(%),median (Q1,Q3) |
41.5(28.8,52.8) | 43.4(28.5,55.0) | 45.5(28.9,55.7) | 0.25 | 48.1(36.3,58.5) | 46.4(34.2,60.1) | 44.7(29.3,56.3) | 0.01 |
| Normal morphology(%),median (Q1,Q3) |
7(4,8) | 6(5,8) | 7(5,8) | 0.7 | 6(5,8) | 6(5,8) | 6(4,8) | 0.84 |
| Normal morphology<4%,n(%) | 23.7(193) | 23.7(96) | 19.7(41) | 0.46 | 23.2(58) | 16.6(27) | 27.4(26) | 0.10 |
P values are derived, unless otherwise noted, using analysis of variance.