Original Article

Association between dental X-ray exposure and the thyroid cancer risk: A meta-analysis of case–control studies

Su-Yeon   Hwang1,*   Hae-Young   Kim1,2,*   Sun-Mi  Song3   Eun-Sil   Choi4   

Department of Public Health Sciences, Graduate School, Korea University
1Department of Health Policy and Management , College of Health Sciences, Korea University
2BK21PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University
3Gangwon Public Health Policy Institute

Abstract

Objectives: Previous studies have reported inconsistent findings in the association between dental diagnostic X-ray exposure and thyroid cancer. This study was a meta-analysis of case–control studies evaluating the association between exposure to dental radiation and the thyroid cancer risk. Methods: We searched the PubMed and EMBASE databases to identify studies on dental radiation and thyroid cancer risks that were published up to September 2018. Quality of studies was assessed using the Newcastle–Ottawa scale. A fixed-effects model was used to estimate pooled odds ratios (ORs) and 95% confidence intervals (CIs) using STATA 14.0. Potential publication biases were evaluated using Egger's test and Begg's funnel plot. Results: From the literature search, we included six case–control studies in this meta-analysis. The meta-analysis using the fixed-effects model found that dental X-ray exposure was associated with 2.34 times increased risk for thyroid cancer (OR=2.34, 95% CI=1.79–3.21). There was no heterogeneity in the data (p=0.662, I2=0%). Egger's test showed that there was no publication bias (p=0.532). Conclusions: This meta-analysis confirmed the association of dental X-ray exposure and thyroid cancer risk. The current results underscore the importance of applying safety regulations at dental clinics to protect thyroid glands during dental radiography examinations.

Figures & Tables

Fig. 1. Flow diagram of screening eligible studies for final inclusion