An overactive or underactive thyroid may worsen periodontal disease, shining a light on the importance of monitoring the oral health of patients with thyroid dysfunction. The review was recently published in BMC Oral Health.
Additionally, thyroid dysfunction may affect clinical attachment level (CAL) and pocket probing depth (PPD), the authors wrote.
"Our systematic review and meta-analysis indicate a significant association between thyroid dysfunction and increased periodontal disease indices," wrote the authors, led by Jing Ni of the Xi'an Medical University in China (BMC Oral Health, February 22, 2023, Vol. 25, 289).
For this study, a comprehensive search was conducted across Medline, Scopus, Web of Science, and Google Scholar from inception to September 2024. The review included studies on adults with diagnosed thyroid dysfunction and healthy controls. Specific thyroid conditions, such as autoimmune thyroiditis, Graves' disease, and Hashimoto's thyroiditis, were also considered.
Data were extracted on thyroid function tests and periodontal disease indices. Study quality and risk of bias were assessed using funnel plots, Begg's and Egger's indices, and the Cochrane tool, while effect sizes were calculated using standard mean difference (SMD) with meta-analysis software, they wrote.
The search yielded eight studies, revealing that patients with thyroid dysfunction had significantly higher periodontal disease indices than controls, with a pooled SMD of 0.369 (95% confidence interval [CI]: 0.194 to 0.545, p < 0.001).
Three studies examined the gingival index, showing no significant effect of thyroid dysfunction (0.388 SMD, 95% CI: -0.230 to 1.007, p = 0.218). Similarly, no significant impact was found on serum interleukin-6 (IL-6) (n = 4, 0.649 SMD, 95% CI: -0.045 to 1.343, p = 0.067) or salivary IL-6 (n = 4, 0.404 SMD, 95% CI: -0.313 to 1.120, p = 0.269), they wrote.
Additionally, thyroid dysfunction had no significant effects on mean plaque index (n = 4), papillary bleeding index (n = 2), serum tumor necrosis factor (TNF-α) (n = 4), or salivary TNF-α (n = 3) (p > 0.05 for all). However, its effects on mean CAL (n = 3, 2.339 SMD, 95% CI: 0.589 to 4.088, p = 0.009) and mean PPD (n = 2, 0.454 SMD, 95% CI: 0.159 to 0.748, p = 0.003) were statistically significant.
Nevertheless, the study had limitations. The low quality of the included studies, due to lack of randomization and blinding, raises concerns about the reliability of the findings, the authors added.
"Future investigations should also explore the underlying mechanisms by which thyroid dysfunction may influence periodontal disease, ultimately contributing to improved management strategies for patients with coexisting thyroid and periodontal conditions," Ni and colleagues wrote.
