Abstract
While cigarette smoking is generally accepted to be the primary behavioural risk factor for periodontal attachment loss (AL), the role of regular marijuana smoking in the aetiology of AL is less clear.
Objectives: To estimate the association between marijuana dependency and periodontitis among young adults after allowing for long-term cigarette smoking.
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. Cigarette smoking exposure had been documented at ages 15, 18, 21, 26 and 32, and those who met the DSM-IV criteria for marijuana dependency at ages 21 and 26 were identified.
Results: Of the 792 individuals for whom complete data were available, 10.0% and 8.6% were marijuana-dependent (MD) at ages 21 and 26 respectively, with 4.8% dependent at both ages. With cigarette smoking: 51.5% had never smoked; 31.2% smoked at age 32; and 17.3% were former smokers. Of those who were MD at age 32, 69.1% were also smokers. The prevalence of 1+ sites with 4+mm AL at age 32 was higher among those who were MD than those who were not (63.2% and 24.0% respectively; P<0.0001), and stratification by smoking status at age 32 showed AL prevalence to be considerably greater among MD participants than non-MD individuals. Similar patterns were observed with repect to the incidence of AL between ages 26 and 32, and when longer-term MD was examined. Logistic regression modelling showed that, after controlling for smoking exposure, sex and plaque, MD individuals were 3.1 times as likely (95%CI 1.8, 5.4) to have established periodontitis by age 32.
Conclusion: marijuana dependency has detrimental periodontal effects over and above those of cigarette smoking.