Exposure measurement in the association between periodontal disease and prematurity/low birth weight

Aim: To compare the use of different definitions for exposure measurement in cases of association between periodontal disease (PD) and prematurity and/or low birth weight (PLBW). Material and Methods: A database from a previous case-control study was used to compare four different definitions for periodontitis: at least one site with probing depth >= 4 mm (1); at least one site with clinical attachment loss (CAL)>= 3 mm (2); at least four teeth with one or more sites presenting probing depth >= 4 mm, with CAL >= 3 mm at the same site (3); and at least four teeth with one or more sites with probing depth >= 4 mm, with CAL >= 3 mm at the same site and presence of bleeding on probing (4). The PD frequency, diagnostic values and adjusted association measurements were calculated. Results: PD frequency ranged from 33.1% to 94.7%. Odds ratio(adjusted) varied slightly according to the exposure measurement used. Conclusions: The association between PD and PLBW weight was consistent, except for exposure measurement 1, i.e. using at least one site with CAL >= 3 mm for periodontitis diagnosis, while the magnitude of this varied according to the definition established.