OBJECTIVE: To determine an association between iodine deficiency and the incidence of thyroid carcinoma among adult Filipino patients consulting at the Philippine General Hospital.

METHODS: This is a comparative cross-sectional study of all patients referred to the Section of Endocrinology with nodular goiter who underwent thyroidectomy from May 2006 to Jan 2007 at the PGH. One hundred sixty four patients were included. After giving their informed consent, each patient was interviewed and examined. Urine was collected and urine iodine measured using the rapid urinary iodine colometeric test kit by Merck Laboratory.

RESULTS: The overall prevalence of iodine deficiency among patients with thyroid nodules is high at 63.4%. The prevalence of malignant thyroid nodules among patients with iodine deficiency is not significantly different compared to patients who are iodine sufficient (55.8% vs 40%, p=0.052). Among patients with malignant nodules, 39.7% had follicular or follicular variant papillary Ca in the iodine deficient group compared to 29.2% in the iodine sufficient group. These proportions were not statistically significant (p=0.37). Lastly, in terms of extent of malignant lesion, among patients with iodine deficiency, 46.6% of patients had extensive lesions versus 25% in the iodine sufficient group. Again, the difference between the two groups was not statistically significant (p=0.07).

CONCLUSION: Despite the government efforts to eliminate iodine deficiency in our country, this remains as a significant health problem among adult Filipinos with thyroid nodules. It may be a risk factor for nodular thyroid disease and these results show that it may also play a crucial role in promoting the development of thyroid carcinoma, although more patients are needed to accurately evaluate the association between iodine exposure and risk of thyroid carcinoma.