Oral hygiene and dental status as factors related to asthma in high school and college students

Objective: Considering that oral microbiota might modulate immune responses, we explored if customary oral care procedures might influence immune-driven diseases such as asthma. Methods: This was a retrospective, cross-sectional analysis of responses to a self-completion medical questionnaire applied to subjects entering into college and high school programs during 2006-2011. Results: Responses from 329 780 students aged 14-24 years (97.6% of the original population) were analyzed. The prevalence of lifetime asthma was 4.01%. Subjects with asthma were slightly older, taller and heavier than subjects without asthma, and these differences were equally present in males and females. Subjects currently having two or more decayed teeth had asthma less frequently than those with one or none decayed tooth, with an odds ratio (OR) = 0.86 and 95% confidence interval (95% CI) 0.83-0.89. In contrast, asthma was reported more frequently among students having two or more missing or filled teeth [OR = 1.1 (95% CI 1.04-1.17) and OR = 1.05 (95% CI 1.01-1.09), respectively]. From 2008 onwards, subjects also responded questions about oral hygiene incorporated into the core questionnaire. In these subjects, the use of toothpaste as well as the frequency and duration of toothbrushing were unrelated to asthma; regular use of mouthwash was associated with asthma in women [OR = 1.16 (95% CI 1.07-1.25)], but not in men [OR = 1.04 (95% CI 0.96-1.13)]. Results of multiple logistic regressions were in line with these findings. Conclusions: Our results suggested that oral hygiene and dental status could be novel factors influencing asthma development, and thus further studies to confirm and clarify this association are warranted.