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Table 1 Demographic characteristics of extraction and non-extraction cohorts

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

  Non-extraction Cohort Extraction Cohort p-value
(people) (%) (people) (%)  
Total 104,903   104,903   
 Male 35,111 33.5 35,111 33.5 1.0
 Female 69,792 66.5 69,792 66.5  
Age      1.0
 60–69 76,570 73.0 76,570 73.0  
 70–79 25,699 24.5 25,699 24.5  
  ≥ 80 2634 2.5 2634 2.5  
Residential Area      <.001a
 Urban 59,487 56.7 59,487 56.7  
 Rural 45,416 43.3 45,416 43.3  
Eligibility      <.001a
 Head of household 44,292 42.2 43,901 41.8  
 Family member 52,292 49.8 55,647 53.0  
 Medical aid beneficiaries 8319 7.9 5355 5.1  
Income level      <.001a
 First quintile 24,361 23.2 21,088 20.1  
 Second quintile 13,851 13.2 12,681 12.1  
 Third quintile 15,795 15.1 14,576 13.9  
 Fourth quintile 21,811 20.8 22,506 21.5  
 Fifth quintile 29,085 27.7 34,052 32.5  
History of dental caries      <.001a
 No 74,615 71.1 50,473 48.1  
 Yes 30,288 28.9 54,430 51.9  
History of periodontal treatment      <.001a
 No 73,599 70.2 42,282 40.3  
 Yes 31,304 29.8 62,621 59.7  
Onset of dementia      <.001a
 No 93,711 89.3 92,051 87.7  
 Yes 11,192 10.7 12,852 12.3  
  1. aStatistically significant at a 95% confidence interval