Background: Few investigations have reported on risk factors for periodontal attachment loss over time in subjects with no home or professional dental care. The purpose of this report was to identify potential risk factors for progression of periodontal attachment loss among male Sri Lankan tea laborers who participated in a 20-year investigation of the natural history of periodontal disease.
Methods: Data for this report were obtained from the 154 subjects who participated in the 1970 baseline and the final 1990 examinations and included data from their interim examinations performed in 1971, 1973, 1977, 1982, and 1985. Oral health assessments included: 1) attachment levels in millimeters on mesial and mesio-buccal surfaces of all but third molar teeth; 2) plaque index (PI); 3) gingival index (GI); 4) calculus index (CI); 5) caries index (DMFS); and 6) presence or absence of teeth. Other variables included age, history of smoking, and/or use of betel nut. Statistical analyses used multivariate repeated measures analysis of variance (ANOVA).
Results: The final adjusted model indicated that attachment loss increased significantly with age (X2 = 74.0; df = 1), GI (X2 = 45.5; df = 1), CI (X2 = 52.7; df = 1) and follow-up time (X2 = 219.8; df = 6, P<0.0001 for all variables).
Conclusions: Age, GI, CI, and time were significantly associated with mean attachment loss over 20 years. Neither PI, history of smoking, or history of betel nut use were significantly associated with attachment loss over time.