Obesity during childhood and adolescence, as determined by elevated body mass index (BMI) z (standard deviation)-scores, was associated with an increased risk of malignant thyroid nodules, authors of a retrospective, cross-sectional study in JAMA Network Open reported. The investigators concluded that BMI z-scores — which are adjusted for a child’s age and sex — may be a significant clinical factor to consider when making decisions about thyroid nodule surgery.
Included in the study were children and young adults (N=116) aged 21 years and younger who underwent surgery for a thyroid nodule between 2003 and 2019 at the Monroe Carell Junior Children’s Hospital at Vanderbilt University Medical Center, Nashville, Tennessee. Thyroid nodule characteristics were correlated with patient demographics. Obesity in childhood and adolescence was defined as a BMI z-score greater than 1.65, which is in the 95th percentile or greater for age- and sex-specific BMI.
Median age of the patients was 16.1 years (range, 0.4-21.0 years). Eighty percent were female and 87% were White. The median BMI z- score was 0.9 (interquartile range [IQR], 0.0-2.0).
Stratified by malignancy status, benign nodules were more frequently associated with Black patients (10% benign vs 4% malignant) and Asian patients (3% vs 0%, respectively). Among Hispanic patients, all had malignant nodules (0 benign vs 7% malignant; P =.03). Benign nodules were associated with lower BMI z-scores, compared with malignant nodules (median, 0.7 vs 1.4; P =.02).
Importantly, the investigators said, patients with higher BMI z-scores did not always have larger thyroid nodules (r, 0.135; P =.24) or more extensive disease in their neck (r, 0.197; P =.33) at presentation than their lower BMI z-score counterparts. However, higher BMI z-scores were significantly and independently associated with the probability of malignant thyroid nodules at presentation (odds ratio [OR], 1.551; 95% CI, 1.212-2.145; P =.008).
This study was limited by its retrospective cross-sectional nature and moderate size but “was rigorously controlled for multiple variable that are often associated with obesity or socioeconomic status,” the researchers wrote.
The investigators said their findings indicate that higher BMI-z scores during childhood and adolescence likely increase the risk for thyroid neoplasm malignancy. This confirms evidence from adults which associates obesity with increased risk for most cancers, including thyroid cancer.
Unlike thyroid cancer in adults, the investigators did not observe a correlation between malignancy and ethnicity. These discrepancies may indicate that the disease process in pediatric thyroid cancer is different from that seen in adulthood.
Guidelines suggest that surgical decision-making in younger patients may be informed by clinical factors that alter the risk of malignant neoplasms,” the authors concluded. “Our study suggests that BMI z-score should be considered such a clinical factor and considered when making the decision to proceed with surgery for a thyroid nodule in a younger patient.”
Ortega CA, Gallant J-N, Chen S-C, et al. Evaluation of thyroid nodule malignant neoplasms and obesity among children and young adults. JAMA Netw Open. Published online July 9, 2021. doi:10.1001/jamanetworkopen.2021.16369