Factors related to number of present teeth in Korean elderly adults aged 55-84 years

The aim of this study was to determine the associations between the number of present teeth (NT) and socio-economic, demographic and oral health behavioural factors among Korean adults aged 55-84 years.

The total subjects comprised 3767 individuals who were examined and who answered the questions on socio-economic status and oral health behaviour from the fourth Korean National Health and Nutrition Examination Survey conducted from 2007 to 2009. The dependent variable was NT, with binary status divided by the median. Socio-economic and demographic factors included gender, educational level, parent's educational levels, region of residence, household income, type of health insurance and mother's economic activity. Oral health behaviours were as follows: daily toothbrushing frequency, smoking status, recent dental visit and illegal dental treatment. Multivariate logistic regression models were applied to explain the associations between NT and other variables.

In a model adjusted by socio-economic, demographic and oral health behavioural variables, subjects who lived in urban areas were more likely to have larger NT compared to those in suburban areas (OR: 1.22, P = 0.025). Males were more likely to have larger NT (OR: 1.90, P < 0.001), and daily toothbrushing frequency was associated with NT (OR = 1.25, P = 0.023). Non-smokers (OR: 2.44, P < 0.001) and past smokers (OR: 1.70, P < 0.001) were more likely to have lager NT compared to current smokers. Subjects without illegal dental treatments were more likely to have lager NT compared to those with illegal dental treatments (OR = 2.21, P < 0.001).

Interventions aiming to preserve present teeth in elderly adults should consider socio-economic, demographic and oral health behavioural factors.