Thyroid nodules and its association with vitamin D in centenarians

Objectives: Thyroid Nodules (TNs) and hypovitaminosis D are common conditions in old people. Our objective was to determine the prevalence of benign and malignant thyroid nodules in centenarians and to examine their associations with serum vitamin D levels. Methods: A population-based survey of 875 centenarians in Hainan, China was conducted. The thyroid glands and neck areas were scanned by board-certified sonographers using standard procedures. Results: The prevalence of thyroid nodules (TN) was 74.2%, with 58.9% in group of possibly benign thyroid nodules (TIRADS 2, 3) and 15.5% in group of possibly malignant thyroid nodules (TIRADS 4A, 4B, 4C, 5). An analysis of logistic regression revealed that serum vitamin D levels were independently associated with increased thyroid nodule prevalence. We observed an inverse dose-effect relationship between TNs and serum vitamin D status with full adjustments (P for trend = 0.025%). For the severely vitamin D deficient group, the deficient group, and the insufficient group, respectively, odds ratios and 95% confidence intervals (OR: CI) for possibly malignant TNs were 3.46 (1.26-9.51), 2.15 (1.08-4.28), and 1.41 (0.72-2.75), compared to the optimal vitamin D status group. The multivariable OR with a 5 ng/mL decrease in serum vitamin D levels was 1.16 (95% CI: 1.01-1.33), for possibly malignant TNs in centenarians. Conclusions: Nearly three-quarters of centenarians were found to have thyroid nodules. Most of these nodules were benign and did not possess any suspicious ultrasound findings. Vitamin D deficiency was associated with thyroid nodules as suggestive characteristics of malignancy in this population.