Table 3 The general characteristics of included studies

Ali Movafegh [15]

27.0 ± 3.4/27.6 ± 4.1

38.9 ± 0.4/39.0 ± 0.6

H. Abdel-Aleem [16]

26.34 ± 5.16/26.62 ± 5.05

39.32 ± 1.15/39.31 ± 1.17

3188.47 ± 458.20/3199.18 ± 444.54

Mehmet B. Sentu ̈rk [17]

30.20 ± 6.83/29.22 ± 6.93

Anuradha Ghosh [18]

25.94 ± 3.78/26.04 ± 3.39

38.62 ± 0.779/38.72 ± 0.671

Haitham Torky [19]

30.7 ± 4.66/30.8 ± 4.37

26.87 ± 6.19/27.17 ± 5.83

Abd El-Naser Abd El-Gaber [20]

27.14 ± 4.986/26.77 ± 4.942

38.32 ± 1.124/38.24 ± 1.518

32.88 ± 2.76/33.59 ± 3.22

Forozan Milani [21]

29.33 ± 5.59/31.2 ± 5.53

37.93 ± 0.69/37.86 ± 0.81

Zahra Naeiji [22]

27.16 ± 4.64/27.89 ± 4.44

38.70 ± 2.66/38.50 ± 2.83

29.34 ± 2.11/28.58 ± 2.79

3207.40 ± 459.70/3218.30 ± 423.79

Amr H. Yehia [23]

28.4 ± 4.9/28.6 ± 4.7

39.1 ± 1.1/39.0 ± 1.2

27.2 ± 1.6/27.5 ± 2.0

Cohort Studies

Upasana Goswami [24]

23.6 ± 2.5/24.3 ± 2.6

22.4 ± 1.6/22.8 ± 1.6

Ming-ying Gai [25]

29.71 ± 4.18/29.75 ± 4.01

38.80 ± 1.11/38.67 ± 1.03

Tullika Singh [26]

25 ± 1.46/30 ± 1.24

39.1 ± 1.24/39.3 ± 1.28

A. V. Chandak [27]

24.3 ± 2.6/23.6 ± 2.5

Leila Sekhavat [28]

26.2 ± 4.7/27.1 ± 4.1

Irene Ray [29]

25.00 ± 4.71/25.88 ± 5.39

38.92 ± 1.38/39.02 ± 1.42

S.J. Dhivya Lakshmi [30]

26.77 ± 2.807/26.82 ± 2.801

29.38 ± 1.2/29.12 ± 2.3

Khing Rushulo [31]

26.6 ± 5.0/28.8 ± 4.7

P. Malathi [32]

23.40 ± 3.06/23.59 ± 3.56

Samir Abd Allah Ali [33]

27.81 ± 5.07/28.32 ± 4.65

38.19 ± 0.7/38.22 ± 1.1

29.24 ± 3/29.55 ± 3.08

Ayman A. Soliman [34]

21.46 ± 2.71/21.46 ± 2.71

39.34 ± 0.47/39.28 ± 0.45

29.01 ± 2.23/28.22 ± 2.06

Noshina Shabir [35]

26.01 ± 4.69/26.79 ± 5.39

37.95 ± 1.41/38.97 ± 1.44