Fig. 3

Incidence rate ratios for the interaction of systemic inflammation and periodontitis on mortality. Observed crude incidence rate ratios for the interaction between inflammation score and periodontitis score regarding all-cause mortality (A) and CVD mortality (B) as well as the interaction between C-reactive protein and mean clinical attachment level regarding all-cause mortality (C) and CVD mortality (D). Blue bars represent observed IRRs whereas green bars represent the expected IRRs for the strata having high measures for both, inflammation and periodontitis, in case of biological (additive scale) or statistical (multiplicative scale) independence of effects. Cut-off values for strata definition: I-Score: 0.3; P-Score: 0.3; CRP: 2.7 mg/l; mean CAL: 3.0 mm. Abbreviations: IRR, incidence rate ratio; I-Score, inflammation score; P-Score, periodontitis score; CVD, cardiovascular disease; CRP, C-reactive protein; CAL, clinical attachment level