Furthermore, we performed logistic regression to test the assumption of serum prolactin level as a risk factor (predictor) for both the bone mineral density (measured by DEXA test) as well as the severity (stages) of periodontitis (outcomes), and the results revealed a statistically significant direct relation (with odds ratios of 0.991 and 0.988, respectively), as shown in Table 6. This evidence concerns the gene PRL and periodontitis.