Ayrton Ilolo Bangolo

  • Designation: Department of Medicine, Hackensack Meridian Health/Palisades Medical Center
  • Country: USA
  • Title: Exposure to heavy metals and thyroid malignancy: Risk Factors and Epidemiology in the Democratic Republic of Congo


Background: Several trace minerals have been shown to be associated with the cause for malignancy. Of which, thyroid cancer as had in increasingly proportion of those cases and has attracted particular attention in the biomedical literature. Despite this, there is a paucity of data on the characteristics of thyroid nodules in different mineral rich regions, such as the Democratic Republic of Congo (DRC). The objective of this study is to establish the spectrum of thyroid nodules in different regions of the most mineral wealthy country in the world and establish epidemiologic patterns.

Method: We conducted a cross-sectional study, performing descriptive statistics and logistic regression with a p value <0.05 determined to be statistical significance. We enrolled 529 patients diagnosed with thyroid nodules between 2005 and 2019 in two of the richest provinces in minerals (Katanga and South Kivu) in the capital city, Kinshasa.

Results: The mean age was 44.2±14.6 years with a female predominance, with a female to male ratio of 5.4. 66.5% of patients had a family history of thyroid disease. 74 patients had simple nodules, whereas 455 had multiple nodules. 87.7% of patients with nodules were euthyroid. The nodules mostly presented a solid structure (72.2%), hypoechogenicity (84.5%), a macronodule (59.8%), calcification (14.4%) and lymphadenopathy (15.5%). 22.3% of these nodules had a malignant character. The independent factors associated with this malignancy were age ≥60 years (aOR=2.81), Katanga as province of origin (aOR=8.19), solid echostructure (aOR=7.69), hypoechogenicity (aOR=14.19), macronodule (aOR=9.13), calcification (aOR=2.6) and the presence of adenopathy (aOR=6.94).

Conclusion: By the way of this large cross-sectional analysis, we demonstrated that thyroid nodules were more likely to be malignant if found in patients originating from the mineral rich region of Katanga. This high frequency of malignancy in mineral rich regions perhaps requires measures aimed at early detection in this population, lower threshold for suspicion of malignancy and adequate training of doctors involved in the management of these patients. We hope this study will pave the way for future, more extensive, studies to better understand the relationship of heavy metals and thyroid cancer incidence and prevalence in heavy metal rich countries in the world.

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