Abstract
OBJECTIVES: The association between oral lichen planus and thyroid disorders, especially hypothyroidism and Hashimoto's thyroiditis, has been discussed in current literature with conflicting outcomes. MATERIALS AND METHODS: The study retrospectively evaluated the thyroid status in patients diagnosed with oral lichen planus and oral lichenoid lesions. A case-control approach was used to prove that thyroid disorders were statistically significant risk factors for oral lichen planus and oral lichenoid lesions. STATISTICAL ANALYSIS: To evaluate these associations, odds ratios (ORs) were used. ORs precision and statistical significance were estimated using a 95% confidence interval (CI) and p-value, respectively. RESULTS: A total of 307 patients were involved in the study: 158 females and 149 males. OR, 95% CIs, and p-values were analyzed. Patients with thyroid diseases showed an increased risk of developing oral lichen planus (OR: 4.29, 95% CI: 1.85-9.96, p-value: 0.0007) and oral lichenoid lesions (OR: 2.76, 95% CI: 1.24-6.13, p-value: 0.0129). This association was maintained in patients with oral lichen planus, while also considering hypothyroidism (OR: 3.74, 95% CI: 1.46-9.58, p-value: 0.0059) and Hashimoto's thyroiditis (OR: 4.57, 95% CI: 1.58-13.23, p-value: 0.005) alone. The correlation of hypertension, diabetes, dyslipidemia, and smoking status with oral lichen planus and oral lichenoid lesions was also evaluated but no statistical significance was found. CONCLUSION: Even if further investigations are needed, the association between oral lichen planus and oral lichenoid lesions with thyroid pathologies should be taken into consideration by endocrinologists due to the potential malignancy of these disorders.