Radioiodine studies, low serum thyrotropin, and the influence of statin drugs

Is Statin Use Associated With Risk of Thyroid Diseases? Results of a Retrospective Cohort Study

BACKGROUND

Given the ubiquity of statin use and prevalence of thyroid diseases, such as thyroid cancer, hyperthyroidism, and thyroiditis, understanding their association deserves further attention.

OBJECTIVE

To examine the association between statin use and thyroid cancer, thyrotoxicosis, goiter, and thyroiditis.

METHODS

Using Tricare data, 2 propensity score (PS)-matched cohorts of statin users and nonusers were formed: (1) a PS-matched general cohort (all patients aged 30-85 years) and (2) a PS-matched healthy cohort (excluded patients with cardiovascular diseases or severe comorbidities). Outcomes were thyroid cancer, thyrotoxicosis, goiter, and thyroiditis. Odds ratios (ORs) and 95% CIs of outcomes were estimated using conditional regression analysis.

RESULTS

Of 43 438 patients, the PS-matched general cohort matched 6342 statin users to 6342 nonusers. The OR of thyroid cancer was 0.62 (95% CI = 0.39-0.996). There was no significant difference between statin users and nonusers in risk of thyrotoxicosis (OR = 0.88; 95% CI = 0.71-1.09), goiter (OR = 0.9; 95% CI = 0.77-1.03), or thyroiditis (OR = 0.78; 95% CI = 0.53-1.15). In the PS-matched healthy cohort (3351 statin users to 3351 nonusers), there was no difference between statin users and nonusers in any outcome. Limitations of the study include its retrospective observational design and use of administrative codes in outcomes ascertainment.

CONCLUSION AND RELEVANCE

This study did not demonstrate any association of statins with harmful effects on thyroid diseases, which offers assurance to clinicians and patients. Furthermore, statin use appears to be associated with a decreased risk of thyroid cancer, but more studies are needed.

Relationship between metabolic syndrome and multinodular non-toxic goiter in an inpatient population from a geographic area with moderate iodine deficiency

BACKGROUND

Obesity and insulin resistance predispose individuals to the development of both metabolic syndrome and non-toxic nodular thyroid diseases.

AIM

The aim of this observational, cross-sectional study is to evaluate the relationship between metabolic syndrome and multinodular nontoxic goiter in an inpatient population from a geographic area with moderate iodine deficiency.

SUBJECTS AND METHODS

We examined 1422 Caucasian euthyroid inpatients. Thyroid volume was determined by ultrasound of the neck. A fine-needle aspiration biopsy was performed to evaluate single thyroid nodules and dominant nodules ≥15 mm in euthyroid multinodular goiter. The diagnosis of metabolic syndrome was made according to the criteria of the American Heart Association/ National Heart, Lung, and Blood Institute.

RESULTS

Of the sample, 277 patients had clinical evidence of multinodular nontoxic goiter, 461 met the criteria for the diagnosis of metabolic syndrome, and 132 were found to have both conditions. After adjusting for age, gender, body mass index, nicotinism, parity, alcohol intake, thyroid function, and metabolic syndrome- related pharmacological treatment, metabolic syndrome was found to be an independent risk factor for the occurrence of multinodular non-toxic goiter. The relationship between metabolic syndrome and multi nodular non-toxic goiter was apparent in both men and women.

CONCLUSIONS

In this study of euthyroid inpatients, we demonstrate that metabolic syndrome is an independent risk factor for the occurrence of multinodular non-toxic goiter in a geographic area with moderate iodine deficiency. We propose that patients meeting the criteria for metabolic syndrome should be screened for the presence of multinodular non-toxic goiter.