Abstract
Thyroid cancer (TC) has inflicted huge threats to the health of mankind. Chlorophenols (CPs) were persistent organic pollutant and can lead to adverse effects in human health, especially in thyroid. However, epidemiological studies have revealed a rare and inconsistent relationship between internal exposure to CPs and TC risk. The purpose of this study was to investigate the correlation between urinary CPs and TC risk in Chinese population. From June 2017 to September 2019, a total of 297 histologically confirmed TC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Gas chromatography-mass spectrometry (GC-MS) was used to determine the levels of three CPs in urine. Conditional logistic regression models were adopted to assess the potential association. Restricted cubic spline function was used to explore the non-liner association. After adjusting for confounding factors, multivariate analysis showed that, compared with the first quartile, the fourth quartile concentrations of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were associated with TC risk (odds ratio (OR)2,4-DCP =2.28, 95% confidence interval (CI): 1.24-4.18; OR2,4,6-TCP =3.09, 95% CI: 1.66-5.77; ORPCP =3.30, 95% CI: 1.71-6.36, respectively), when CPs were included in the multivariate model and restricted cubic spline function as continuous variables, presenting significant dose-response relationships. Meanwhile, whether in the TC group with tumor diameter > 1 cm or metastatic TC, the changes of 2,4,6 TCP and PCP concentrations were positively correlated with the risk of TC. Our study suggests that higher concentrations of urinary CPs are associated with increased TC risks. Moreover, 2,4,6-TCP and PCP have certain effects on the invasiveness of thyroid cancer. Targeted public health policies should be formulated to reduce the CP pollution. These findings need further in-depth studies to confirm and relevant mechanism also needed to be clarified.
Highlights
Thyroid cancer, one of the most common endocrine-related tumors originating from follicular or para-follicular cells, constitutes a serious burden of disease worldwide due to its rapidly growing incidence (Kato and Niebuhr, 2018)
After adjusting for these confounding factors, the risk of thyroid cancer was increased by 209% and 230% for trichlorophenol and pentachlorophenol, respectively
Given that papillary thyroid carcinoma accounted for 92.9% of the total cases and was the main subtype of thyroid cancer, we performed a subgroup analysis of papillary thyroid carcinoma patients and the results were shown in Supplementary Table 1
Summary
One of the most common endocrine-related tumors originating from follicular or para-follicular cells, constitutes a serious burden of disease worldwide due to its rapidly growing incidence (Kato and Niebuhr, 2018). According to National Cancer Center of China, the incidence rate of thyroid cancer in 2015 was 14.6 per 100,000, nearly three times higher than that in 2005, and it has become the fourth most common malignant tumor among women (Zheng et al 2019). Most of thyroid cancer patients with a favorable 10-year overall survival rate, above 20% of patients remain at risk of tumor recurrence for several years after operation (Dong et al 2019). Some of the traditional risk factors for thyroid cancer still could not explain this epidemic dynamic situation, including sex, radiation exposure, abnormal iodine intake, a family history of thyroid disease and metabolic syndrome (Kitahara et al 2018; Rubio et al 2018). This study was designed to examine the association between urinary CPs and risk of TC in Chinese population
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