A hidden periodontitis epidemic during the 20th century?

Objectives: Increasing evidence suggests a strong causal link between smoking and periodontitis. The goal of this study was to impute how the secular changes in smoking prevalence during the 20th century impacted the advanced periodontitis incidence in the US. Methods: Epidemiological analyses based on US prevalence data of advanced periodontitis and smoking, and predictions of future smoking prevalence. Results: Assuming other risk factors for periodontitis remained constant, we estimated that the incidence of advanced periodontitis decreased by 31% between 1955 and 2000. The changes in smoking habits, and consequently the changes in periodontitis incidence, depended strongly on education and gender. Between 1966 and 1998, we estimated a 43% decreased periodontitis incidence among college-educated individuals versus only an 8% decrease among individuals with less than a high school education. Between 1955 and 1999, we estimated a 41% decrease among males versus a 14% decrease among females. By the year 2020, the incidence of advanced periodontitis may decrease 43% from its level in 1955. Conclusions: A periodontitis epidemic fueled by smoking remained hidden for most of the 20th century. Because this epidemic was hidden, it distorted our understanding of the treatment and etiology of periodontitis. The socioeconomic polarization of this epidemic will dictate alterations in patterns of periodontal care.