Table 4.

Mean annual tooth loss in the diabetes mellitus group and the control group (patients with acute upper respiratory inflammation) according to number of visits to institutions

Variable	Control group			Diabetes mellitus group
	n	Mean	SD	n	Mean	SD
Annual number of visits to medical institutions
Subgroup 1	1,202,251	0.172	0.483	341,590	0.246	0.586
Subgroup 2	1,336,361	0.156	0.454	405,577	0.251	0.588
Subgroup 3	1,330,762	0.152	0.450	410,629	0.230	0.564
Subgroup 4	1,379,031	0.149	0.448	412,286	0.216	0.554
Annual numbers of visits to dental institutions
Subgroup 1	1,149,442	0.028	0.173	465,319	0.063	0.261
Subgroup 2	1,445,096	0.071	0.280	365,130	0.144	0.407
Subgroup 3	1,172,363	0.156	0.423	375,668	0.275	0.576
Subgroup 4	1,481,504	0.340	0.671	363,965	0.505	0.836

Patients in control and diabetes mellitus groups were divided into two further groups according to the annual number of visits to medical and dental institutions, and these were stratified into four subgroups, by referencing the 25th, 50th and 75th percentiles:

Annual number of visits to medical institutions: control group. Subgroup 1: 1–6 visits; subgroup 2: 7–13 visits; subgroup 3: 14–23 visits; subgroup 4: ≥24

Annual number of visits to medical institutions: diabetes mellitus group. Subgroup 1: 1–10 visits; subgroup 2: 11–16 visits; subgroup 3: 17–27 visits; subgroup 4: ≥28 visits

Annual number of visits to dental institutions: control group. Subgroup 1: 1–2 visits; subgroup 2: 3–5 visits; subgroup 3: 6–9 visits; subgroup 4: ≥10 visits

Annual number of visits to dental institutions: diabetes mellitus group. Subgroup 1: 1–2 visits; subgroup 2: 3–5 visits; subgroup 3: 6–10 visits; subgroup 4: ≥11 visits.