Table 1 Demographics, clinical and seminal parameters of the subjects studied

Age (years)

31.9 ± 4.35

32.9 ± 4.39

0.011

BMI (kg/m²)

25.34 ± 3.82

26.22 ± 3.78

0.914

Current smokers (%)

50.6

46.9

0.433

Current alcohol consumption (≥4 drinks/week) (%)

19.4

15.6

0.283

Education level (%)

0.478

 No higher than high school

21.2

20.1

 High school

24.1

29.2

 University and above

54.7

50.7

Monthly household income

0.039

 5000

32.9

32.7

 5000-7000

54.1

45.4

 7000~

12.9

21.8

Night shifts (times/week) (%)

<0.01

 1-2

34.1

13.6

 3-4

7.1

5.3

 >4

0.6

0.9

Type of infertility

0.652

 Primary

95.9

95

 Secondary

4.1

5

Duration of infertility (years) (%)

<0.01

 ≤ 2

62.9

38.1

 2-4

25.9

31.9

 >4

11.2

30.1

Timed intercourse (%)

11.8

23.6

<0.01

Mean testis volume (Prader) (ml)

13.1 ± 3.18

13.2 ± 3.30

0.590

Clinical varicocele (Palpation) (%)

10.0

11.8

0.544

Symptoms of Prostatitis (%)

5.3

7.7

0.318

Seminal parameters

 Sexual abstinence (days)

4.13 ± 1.48

4.14 ± 1.44

0.893

 Semen volume (ml)

3.61 ± 1.41

3.62 ± 1.54

0.184

 Sperm concentration, ×10⁶/ml

65.68 ± 51.94

54.42 ± 45.15

0.472

 Sperm progressive motility (%)

33.89 ± 18.09

29.10 ± 17.29

0.735

 Sperm normal morphology (%)

4.03 ± 2.05

3.73 ± 2.04

0.399