Table 2 Clinical, and demographic characteristics of the subjects included in the study

Nair et al., 2022 [28]

India

Cross-sectional

30

60

90

45^e

45^a

23(2.9)

CP = GI score of > 1, PD of ≥ 5 mm, CAL of ≥ 3 mm, and RBL

G = GI score of > 1, PD of ≤ 4 mm and absence of CAL and RBL

HC = GI score of 0, PD of ≤ 3 mm and absence of CAL and RBL

Wankhede, and Dhadse, 2022 [29]

India

Cross-sectional

15

15

30

NI

37.5(1.0)

CP = PD ≥ 4 mm, and CAL ≥ 4 mm

HC = PD < 3mm, without RBL

Nainee et al., 2020 [30]

India

Cross-sectional

25

50

75

NI

41.3(8.4)

CP = GI > 1, PD ≥ 4 mm, CAL ≥ 3 mm

G = GI > 1, PD ≤ 3 mm, no CAL

HC = No clinical signs of gingival inflammation, absence of BOP, PD ≤ 3 mm, no CAL

Sadeghi et al., 2018 [31]

Iran

Cross-sectional

10

12

22

11^e

9^a

37.9(7.8)

CP = PD ≥ 5 mm, CAL ≥ 3 mm and BOP

HC = Without BOP, gingival inflammation, CAL and PD

Kalate et al., 2018 [32]

Iran

Cross-sectional

30

30

60

28^e

32^a

33.9(5.5)

CP = PD ≥ 5 mm, CAL ≥ 3 mm, presence of BOP, and gingival discoloration

HC = PD < 3 mm, and no clinical symptoms of gingival inflammation

Althebeti et al., 2018 [33]

Saudi Arabia

Cross-sectional

10

20

30

30^e

20–40

CP = PD ≥ 5 mm, and CAL ≥ 3 mm

G = Generalized gingival inflammation with BOP, and no CAL

HC = Clinically healthy gingiva with IP 0, CAL 0, and PD ≤ 3 mm

Mitani et al., 2015 [34]

Japan

Cross-sectional

10

16

26

15^e

14^a

48.5(1.9)

CP = PD ≥ 5 mm, CAL ≥ 6 mm and RBL

HC = PD ≤ 3 mm, BoP%≤10% without RBL

Himani et al., 2014 [35]

India

Cross-sectional

17

33

50

25^e

25^a

36.9(3.2)

CP = GI ≥ 2, CAL ≥ 8 mm, PD ≥ 5 mm

G = GI > 1, CAL0mm, PD ≤ 3 mm

HC = GI ≤ 1, CAL0mm, PD ≤ 3 mm

Nagireddy et al., 2013 [36]

India

Cross-sectional

10

20

30

NI

20–50

CP = PD > 5 mm, and RBL

HC = Clinically healthy periodontium, and no evidence of RBL

Shaker et al., 2012 [37]

Egypt

Cross-sectional

15

25

40

17^e

23^a

32.6(2.6)

CP = Subjects were > 35 years of age with PD and CAL > 5 mm

HC = Subjects were > 20 years of age and had clinically healthy gingival with PI = 0, GI = 0, PD and CAL ≤ 3 mm

Ay et al., 2009 [38]

Turkey

Cross-sectional

20

40

60

26^e

34^a

37.6(1.0)

CP = Subjects with RBL, PD, and CAL > 4 mm

HC = Subjects had no evidence of CAL and RBL

Vernal et al., 2005 [39]

Chile

Cross-sectional

8

16

24

17^e

7^a

37.4(8.0)

CP = Subjects with PD ≥ 5 mm, CAL ≥ 3 mm, and extensive RBL

HC = Subjects with absence of CAL

Summary of variables included in the study ◊

200

337

537

214^e/189^a

36.6(4.2)