Table 3 Summary of included cross-sectional studies

First Author, Year, Country

N

Age

Outcome

Number of Teeth Designation

Results

(95% CI)

Summary

Remaining Teeth

Izuora, [46] 2019,

U.S.A.

301

55.8 ± 11.9*

Heart disease in participants with diabetes

0–28

OR 0.960 (0.926,0.998)

Greater number of healthy teeth decreased prevalence of heart disease.

Itakura, [47] 2018,

Japan

119

86.7 ± 7.8*

Diabetes

0 (0,1.3^†) + denture;

0 (0,6.5^†) + no denture

Referent group

OR 4.45 (1.43,13.88)

Bite instability was significantly associated with increased prevalence of diabetes.

Shin, [48]

2017,

Korea

3963

60.1–63.6 ± 8.8–9.7*

Metabolic syndrome

28

20–27

0–19

Referent group

OR 1.45 (1.10,1.91)

1.58 (1.18,2.13)

Missing any teeth was significantly associated with increased prevalence of metabolic syndrome.

Song, [49]

2017,

Korea

2078

53.0–70.6 ± 0.4–1.1*

Diabetic retinopathy in participants with diabetes

28

20–27

≤ 19

Referent group

OR 4.27 (1.38,13.19)

8.73 (2.69,28.33)

Missing any teeth was significantly associated with increased prevalence of diabetic retinopathy.

Jung, [50]

2015,

Korea

5535

64.9 ± 8.1*

Prediabetes; diabetes

25–32

17–24

1–16

Edentulous

Diabetes: Referent group

OR 1.20 (0.99,1.46)

1.74 (1.35,2.27)

1.72 (1.10,2.70)

Prediabetes: number of teeth significant for linear trend only (p = 0.032)

Missing ≥ 8 teeth was significantly associated with increased prevalence of diabetes but not prediabetes.

First Author, Year, Country

N

Age

Outcome

Number of Teeth Designation

Results

(95% CI)

Summary

Remaining Teeth

Vedin, [51]

2015,

Global

15,828

65.0 (59,71)^†

Diabetes in participants with coronary heart disease

26–32

20–25

15–20

1–14

Edentulous

OR 0.89 (0.85,0.92) for each level of tooth loss

Moving from a higher (no teeth) to a lower tooth loss level decreased prevalence of DM by 11%.

Furukawa, [52]

2007,

Japan

100

59.1 ± 8.4*

Atherogenic factors in participants with diabetes

0–28

Spearman correlation coefficient:

−0.275 (p = 0.006) HbA1c;

0.202 (p = 0.048) HDL

HbA1c significantly inversely correlated and HDL cholesterol significantly positively correlated with number remaining teeth in older adults with diabetes.

Missing Teeth

Huang, [53] 2013,

U.S.A.

70,363

74.0 ± 0.05*

Health-related quality of life in participants with diabetes

0

Any

1–5

≥ 6

Edentulous

Referent group

OR 1.25 (1.13,1.37)

1.08 (0.97,1.20)

1.34 (1.20,1.49)

1.40 (1.25,1.57)

Missing any teeth was significantly associated with HRQOL in older adults with diabetes.