Periodontal disease and smoking to age 32: a cohort study

While smoking has been shown to be the primary behavioural risk factor for periodontal attachment loss (AL), a lack of longitudinal exposure data from people aged in their 20s and 30s means that information is lacking on smoking's role as a risk factor for AL through a key period in the condition's development. Aim: to describe the association between long-term smoking and age-32 periodontitis, and to determine the effects of recent smoking cessation. Methods: In a longstanding prospective cohort study of all individuals born in 1972/73 in Dunedin (NZ), systematic periodontal examinations conducted at age 26 were repeated at age 32. Smoking exposure had been documented at ages 15, 18, 21, 26 and 32. Results: Of the 810 individuals assessed: 51.1% had never smoked; 37.2% had smoked at 1+ of those ages; and 11.7% were smokers at all 5 ages. In those groups, prevalence estimates for 1+ sites with 5+mm AL were 4.3%, 16.9% and 29.5% respectively (P<0.01). Similar patterns were seen with the extent and severity of AL. Among the 25 (3.1%) who had ceased smoking between ages 26 and 32, AL prevalence and severity were similar to the never-smokers. Those “recent quitters” had the highest proportion of individuals categorised as “periodontally healthy” according to criteria based on probing depth and bleeding on probing (Moss et al, 2005). Multivariate modeling confirmed these findings. Conclusion: While smoking through adolescence and adulthood is associated with poorer periodontal health by the early 30s, smoking cessation after the mid-20s appears to increase the likelihood of a return to periodontal health by age 32. Supported by the Health Research Council of New Zealand and NIDCR grant R01 DE-015260-01A1.