title: Obesity Does Not Modify the Risk of Differentiated Thyroid Cancer in a Cytological Series of Thyroid Nodules.
abstract: BACKGROUND
  A possible impact of obesity on the risk of thyroid cancer has been postulated in some studies, but it remains controversial.
  
  
  OBJECTIVE
  To investigate the association between obesity and differentiated thyroid carcinoma in a population of unselected patients subjected to fine-needle aspiration cytology (FNAC) for thyroid nodules.
  
  
  METHODS
  We retrospectively evaluated the results of FNAC of thyroid nodules in 4,849 patients (3,809 females and 1,040 males; mean age 55.9 ± 14.1 years). Patients were stratified according to their body mass index (BMI). There were 1,876 (38.7%) normal-weight patients (BMI 18-24.9), 1,758 (36.2%) overweight (BMI 25-29.9), 662 (13.7%) grade 1 obese (BMI 30-34.9), 310 (6.4%) grade 2 obese (BMI 35-39.9) and 243 (5.0%) grade 3 obese (BMI >40).
  
  
  RESULTS
  The prevalence of suspicious or malignant nodules (Thy4/Thy5) did not differ across the 5 BMI groups, i.e. it was 6.8% in normal-weight patients, 6.3% in overweight patients, 6.3% in grade 1 obese patients, 4.0% in grade 2 obese patients and 4.2% in grade 3 obese patients (p = 0.29). The prevalence of Thy4/Thy5 nodules did not differ when males and females were evaluated separately (p = 0.22 and p = 0.12, respectively). A significant, lower rate of Thy4/5 cytology was observed in female patients with grade 2-3 obesity (odds ratio 0.51; 95% confidence interval 0.284-0.920; p = 0.009).
  
  
  CONCLUSIONS
  The results of this study, in a retrospective series of patients with thyroid nodules, do not confirm previous findings reporting an association between obesity and differentiated thyroid carcinoma. Thus, obese patients with nodular thyroid disease should be managed the same as normal-weight patients.
authors: Unit of Internal Medicine and Endocrinology, Fondazione Salvatore Maugeri I.R.C.C.S., ISPESL Laboratory for Endocrine Disruptors and Chair of Endocrinology, University of Pavia, Pavia, Italy.
authors: Mario
authors: M
authors: Rotondi
authors: Departments of Medical, Surgical and Neurological Sciences, University of Siena, Siena, Italy.
authors: Maria Grazia
authors: MG
authors: Castagna
authors: Department of Medical and Surgical Sciences, University of Brescia, Brescia, Italy.
authors: Carlo
authors: C
authors: Cappelli
authors: Departments of Medical, Surgical and Neurological Sciences, University of Siena, Siena, Italy.
authors: Cristina
authors: C
authors: Ciuoli
authors: Unit of Internal Medicine and Endocrinology, Fondazione Salvatore Maugeri I.R.C.C.S., ISPESL Laboratory for Endocrine Disruptors and Chair of Endocrinology, University of Pavia, Pavia, Italy.
authors: Francesca
authors: F
authors: Coperchini
authors: Departments of Medical, Surgical and Neurological Sciences, University of Siena, Siena, Italy.
authors: Francesco
authors: F
authors: Chiofalo
authors: Departments of Medical, Surgical and Neurological Sciences, University of Siena, Siena, Italy.
authors: Fabio
authors: F
authors: Maino
authors: Departments of Social, Political and Cognitive Sciences, University of Siena, Siena, Italy.
authors: Paola
authors: P
authors: Palmitesta
authors: Unit of Internal Medicine and Endocrinology, Fondazione Salvatore Maugeri I.R.C.C.S., ISPESL Laboratory for Endocrine Disruptors and Chair of Endocrinology, University of Pavia, Pavia, Italy.
authors: Luca
authors: L
authors: Chiovato
authors: Departments of Medical, Surgical and Neurological Sciences, University of Siena, Siena, Italy.
authors: Furio
authors: F
authors: Pacini
keywords: Body mass index; Fine-needle aspiration cytology; Morbid obesity; Thyroid cancer