This was a cohort study. COHORT SELECTION: A longstanding prospective study was carried out of a birth cohort born in Dunedin (New Zealand) in 1972-1973. EXPOSURE MEASUREMENT: Periodontal examinations of the study participants were carried out when they reached the age of 26 and 32 years by calibrated examiners; smoking exposure was measured by questioning at ages 15, 18, 21, 26 and 32 years. Socioeconomic status (SES) was measured at the age of 26 years by categorising adult occupation using standard New Zealand occupation indices. Dental visiting behaviour was assessed by questioning at age 25 and 32 years.Chi-square tests were used to examine the statistical significance of differences observed with categorical dependent variables. Analysis of variance was used for continuous variables. Logistic regression modelling was used to examine smoking exposure and periodontitis prevalence and incidence while controlling for sex, SES, dental plaque accumulation and the use of dental services.Complete data were available for 810 individuals of whom 48.9

作者：Penny, Hodge；Viv, Binnie

来源：Evidence-based dentistry 2009 年 10卷 1期