Descriptive statistics of the study and control groups with the characteristics of the subsamples.

To keep the table transparent, percentages have been rounded to whole numbers. Note that no periodontally healthy smoker psoriasis patients were found. A trend analysis (χ2 with adjusted residuals) revealed a significant trend (χ2 = 48.074, p = 0.000), with non-smoker controls being the less likely to have any stage of periodontal disease and smoker patients being the most likely to have the severe stage. Significance values refer to the comparison of odds with healthy as the reference category (see also Table 3.).