Although obesity is generally linked to the development of many cancers, including thyroid cancer, a cross-sectional study did not find this association in adolescents.
Among 362 patients younger than 19 with thyroid nodules, thyroid cancer was not associated with BMI z score (OR 1.14, 95% CI 0.91-1.43), reported Ari J. Wassner, MD, of Boston Children’s Hospital, and colleagues at JAMA Otorhinolaryngology – Head and Neck Surgery.
However, BMI z score was related to larger nodule diameter (Spearman r=0.12, 95% CI 0.02-0.23), as well as a greater likelihood of undergoing thyroid surgery (OR 1.32, 95% CI 1.08-1.62) .
Looking closer in a multivariate analysis, having a larger nodule diameter was independently related to a higher likelihood of requiring thyroid surgery (OR 1.07, 95% CI 1.05- 1.09). In contrast, the likelihood of undergoing thyroid surgery was no longer significantly related to BMI z score (OR 1.24, 95% CI 0.99-1.54).
“In this cohort, patients with higher BMI were more likely to undergo thyroid surgery, which may be partly due to the association of increased BMI with larger nodules,” the group explained. by Wassner. “We hypothesize that this may reflect greater difficulty in clinically detecting thyroid nodules in children with larger bodies, which delays diagnosis.”
The group noted that a higher BMI is unlikely to be considered an independent risk factor for thyroid cancer in children with thyroid nodules.
“Routine thyroid examination is important in children, and any detected nodules should be evaluated against established risk factors outlined in current consensus guidelines,” they recommended.
This analysis included only patients treated at Boston Children’s Hospital from 1998 to 2020. All patients were evaluated for a non-autonomous thyroid nodule 1 cm or greater in diameter. Overall, thyroid cancer was present in 99 of 362 patients (27%).
“Unresected nodules were considered malignant based on cytology test results or benign based on cytology test results and lack of nodule growth for 1 year or longer or indeterminate cytology test results and of a lack of growth for 2 or more years,” the group explained. As with the resected nodules, the presence of thyroid cancer was assessed histopathologically.
Among the cohort, 80% were girls and the median age was 15.5 years. The majority were Caucasian and only 21% had multiple nodules. Patients were excluded from this analysis if they were at genetic risk for thyroid cancer.
Among the total cohort, the largest nodule diameter was a median of 23 mm and a median of 28 mm in those with thyroid cancer.
Median thyroid-stimulating hormone levels were not different between those with and without thyroid cancer (1.8 mIU/L versus 1.4 mIU/L, respectively). The presence of thyroid cancer also did not differ between genders or between races/ethnicities.
Wassner and his team also performed a subanalysis, looking exclusively at patients who had undergone thyroid surgery (48%), and found that BMI z the score was still not significantly related to the presence of thyroid cancer (OR 0.93, 95% CI 0.68-1.27).
Instead of looking at BMI z score as a continuous variable, the group separately compared patients with a BMI above the 95th percentile to those below. This analysis also came to similar conclusions.
Although these findings contrast with a previous surgical series who actually found an association between BMI z score and malignant nodules, Wassner’s group pointed out that previous studies limited to only resected nodules “may be biased by factors that affect patient selection for surgery.”
Wassner and his co-authors reported no disclosures.