The relationship between vitamin D nutritional status and ultrasound classifications of thyroid nodules in young and middle-aged euthyroid male petroleum workers

Abstract

Abstract Background Previous studies on the relationship between Thyroid Nodules(TNs) and Vitamin D (VD) have produced conflicting results. These discrepancies may be attributed to variations in the study populations, different methods of VD measurement, unclear thyroid function status, and the potential confounding effects of VD2 and VD3. This study was aimed to analyze the relationship between VD2 and VD3 nutritional status and the occurrence risk of TNs in young and middle-aged euthyroid male (YMAEM) petroleum workers without thyroid autoimmunity (TAI). Methods The health check-up database of 2037 YMAEM petroleum workers between the ages of 30 and 60 without TAI was retrospectively analyzed. Serum 25-hydroxy vitamin D [25(OH)VD], 25(OH)VD3 and 25(OH)VD2 levels were assayed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The participants were classified into different groups according to their ultrasound images of TNs based on Chinese-Thyroid Imaging Reporting and Data System (C-TRIADS). C-TRIADS consist of 6 grades, and the upper three indicate TNs with potential malignancy. Results No C-TRIADS 5 or 6 nodules were found in these participants. The serum 25(OH)VD level in the C-TIRADS 4 TN group was significantly lower than that in the C-TIRADS 1, C-TIRADS 2, and C-TIRADS 3 groups. The overall prevalence of TNs was similar among the VD-deficient, insufficient, and sufficient groups. However, the prevalence of patients with C-TIRADS 4 TNs was markedly higher in the VD-deficient group (18.5%) than in the insufficient (5.5%, P.adj < .05) and sufficient groups (4.1%, P.adj < .05). Identical findings were observed among the groups with low, medium, and high serum 25(OH)VD3 levels, but not among those with different serum 25(OH)VD2 levels. A binary logistic regression analysis indicated that, compared to the VD-sufficiency group, the VD-deficiency group [OR = 5.02 (95% CI: 3.08–8.17; P < .001)] significantly increased the risk of developing C-TIRADS 4 TNs. Conclusions VD deficiency [25(OH)VD < 20.00 ng/mL] was an independent risk factor for the development of TNs with malignant ultrasound characteristics in YMAEM petroleum workers without TAI. Low levels of VD3, rather than VD2, may increase the prevalence of C-TIRADS 4 TNs in YMAEM petroleum workers.