PTBP1 and gastroesophageal reflux disease: Based on random forest variable importance values and rankings in Table 3, PTB1, PTB2, PTB3 and PTB4 have strong associations with low socioeconomic status, GERD, age, infertility, irritable bowel syndrome, diabetes, TMD, salivary gland disease, hypertension, tricyclic antidepressant and benzodiazepine.