Association between numbers of decayed teeth and HbA1c in Japanese patients with type 2 diabetes mellitus

Figures & data

Figure 1. Study flow chart. T1DM: type I diabetes mellitus; T2DM: type 2 diabetes mellitus.

Table 1. Subject characteristics.

Characteristics	HbA1c <9.0 (n = 24)	HbA1c ≥9.0 (n = 84)	P^b
Continuous variables^a
Age	64.5 (38–88)	59.0 (33–83)	0.102
BMI	25.52 (18.51–36.20)	26.20 (17.12–54.65)	0.671
Duration of DM (y)	9 (0.083–36)	5 (0.083–31)	0.242
Categorical variables
Sex
Male	15	48	0.815
Female	9	36
Regular dental visits
Yes	18	58	0.623
No	6	26
Smoking status
Current	6	23	0.329
Former	9	19
None	9	42
Alcohol consumption
Current	4	8	0.529
Former	3	16
None	17	60
Regular exercise habit
Yes	9	29	0.812
No	15	55

^a Continuous values are expressed as median (range).

^b Continuous variables were subjected to Mann–Whitney U test. Categorical variables were subjected to Fisher’s exact test.

BMI: body mass index; DC: dental caries; DM: diabetes mellitus; HbA1c: glycated haemoglobin; T2DM: type 2 diabetes mellitus.

Table 2. Caries and periodontal status.

Characteristics^a	HbA1c <9.0 (n: 24)	HbA1c ≥9.0 (n: 84)	P^b
%BOP	23.21 (0–100)	32.74 (0–100)	0.150
%PPD ≥4 mm	18.33 (0–100)	31.07 (0–100)	0.325
DT	0 (0–11)	1 (0–19)	0.006
MT	2.5 (0–25)	3.5 (0–27)	0.558
FT	8.5 (0–24)	6.0 (0–26)	0.142
DMF index	17 (2–28)	17 (1–28)	0.909
MNI (%)	100 (50–100)	92 (5–100)	0.004

^a All values are expressed as median (range).

^b Continuous variables were subjected to Mann–Whitney U test.

%BOP: percentage of teeth with bleeding of probing; DMF: decayed, missing, and filled teeth; DT: number of decayed teeth; FT: number of filled teeth; HbA1c: glycated haemoglobin; MT: number of missing teeth; MNI: Met Need Index; %PPD ≥4 mm: percentage of teeth with periodontal probing depth ≥4 mm.

Table 3. Multiple linear regression analysis of exposure variables on the absolute number of decayed teeth.

	β	SE	95% LCI	95% UCI	P value
Constant	−2.054	2.635	−7.279	3.172	0.438
BMI	0.108	0.072	−0.035	0.251	0.137
Regular dental visits	−2.409	0.851	−4.097	−0.721	0.006
HbA1c (mmol/mol)	0.039	0.017	0.005	0.072	0.025

n = 108.

β: adjusted coefficient; HbA1c: glycated haemoglobin; LCI: lower value of a reliable interval; PPD: periodontal probing depth; %PPD: percentage of teeth with PPD ≥4 mm relative to the total number of teeth present; SE: standard error; UCI: upper value of a reliable interval.

Table 4. Multiple linear regression analysis of exposure variables on the sum of decayed, missing, and filled teeth.

	β	SE	95% LCI	95% UCI	P value
Constant	2.164	5.018	−7.788	12.12	0.667
Age	0.157	0.066	0.027	0.288	0.018
Duration of DM	0.158	0.079	0.002	0.314	0.047
Regular exercise habit	−4.058	1.494	−7.021	−1.095	0.008
HbA1c (mmol/mol)	0.061	0.031	−0.001	0.123	0.053

n = 108.

β: adjusted coefficient; DM: diabetes mellitus; HbA1c: glycated haemoglobin; LCI: lower value of a reliable interval; SE: standard error; UCI: upper value of a reliable interval.

Table 5. Multiple linear regression analysis of exposure variables on the Met Need Index.

	β	SE	95% LCI	95% UCI	P value
Constant	115.1	12.39	90.51	139.6	<0.01
BMI	−0.668	0.339	−1.339	0.004	0.051
Regular dental visits	12.09	4.002	4.150	20.02	0.003
HbA1c (mmol/mol)	−0.216	0.080	−0.374	−0.058	0.008

n = 108.

β: adjusted coefficient; HbA1c: glycated haemoglobin; LCI: lower value of a reliable interval; SE: standard error; UCI: upper value of a reliable interval.