Table 1 Population and characteristics of included studies
study | Country | No. of GD/ DT | Sex (male/female) | Age(year) | ||
|---|---|---|---|---|---|---|
GD | DT | GD | DT | |||
Kumar, 2009 | India | 34/31 | 10/24 | 4/27 | 37.1 (12.7) | 29.1 (9.2) |
Kim, 2015 | Korea | 40/20 | 12/28 | 7/13 | 43.23 ± 14.56 | 41.7 ± 13.97 |
Uchida, 2010 | Japan | 44/13 | 15/29 | 3/10 | 42.1 ± 14.4 | 43.8 ± 17.0 |
Zhao, 2012(1) | China | 103/32 | 29/74 | 12/20 | 45.86 ± 13.6 | 43.06 ± 12.3 |
Zhao, 2012(2) | China | 118/51 | 42/76 | 18/33 | 39.66 ± 13.7 | 45.06 ± 12.1 |
Hiraiwa, 2013 | Japan | 68/33 | 15/53 | 6/27 | 41 (33–54.5) | 37 (29–43) |
Karakas, 2014 | Turkey | 17/7 | 11/6 | 6/1 | 44.3 ± 17 | 43.7 ± 14.6 |
Shafi, 2012 | Turkey | 31/41 | 0/31 | 0/41 | 29.1 ± 5.12 | 29.1 ± 4.8 |
Xue, 2015 | China | 35/33 | 0/35 | 0/33 | 27.25 ± 4.00 | 26.88 ± 4.03 |
Yang, 2017 | China | 30/25 | 0/30 | 0/25 | not clear | not clear |
Donkol, 2013 | Saudi Arabia | 18/8 | not clear | not clear | 31.1 ± 8.4 | 33.1 ± 7.5 |