The effect of missing teeth on dementia in older people: a nationwide population-based cohort study in South Korea

Table 2 Population distribution according to the number of missing teeth in the tooth extraction cohort^a

	The number of missing teeth						p-value
	1–6		7–12		≥13		p-value
	(people)	(%)	(people)	(%)	(people)	(%)
Total	84,411		17,341		3151
Male	27,112	32.1	6613	38.1	1386	44.0	<.001^b
Female	57,299	67.9	10,728	61.9	1765	56.0
Age
60–69	61,829	73.2	12,459	71.8	2282	72.4	<.001^b
70–79	20,398	24.2	4492	25.9	809	25.7
≥ 80	2184	2.6	390	2.2	60	1.9
Residential area
Urban	48,167	57.1	9589	55.3	1731	54.9	<.001^b
Rural	36,244	42.9	7752	44.7	1420	45.1
Eligibility
Head of household	35,076	41.6	7426	42.8	1399	44.4	<.001^b
Family member	44,844	53.1	9165	52.9	1638	52.0
Medical aid beneficiaries	4491	5.3	750	4.3	114	3.6
Income level
First quintile	17,073	20.2	3386	19.5	629	20.0	<.001^b
Second quintile	10,074	11.9	2201	12.7	406	12.9
Third quintile	11,513	13.6	2561	14.8	502	15.9
Fourth quintile	18,139	21.5	3729	21.5	638	20.2
Fifth quintile	27,612	32.7	5464	31.5	976	31.0
Experience of dental caries
No	41,170	48.8	7898	45.5	1405	44.6	<.001^b
Yes	43,241	51.2	9443	54.5	1746	55.4
Experience of periodontal treatment
No	35,306	41.8	5964	34.4	1012	32.1	<.001^b
Yes	49,105	58.2	11,377	65.6	2139	67.9
Onset of dementia
No	74,230	87.9	15,083	87.0	2738	86.9	<.001^b
Yes	10,181	12.1	2258	13.0	413	13.1

^aIt is helpful to refer to Table 1 to see statistical differences from the sample population shown in this table
^bStatistically significant at a 95% confidence interval