Fig. 1
From: Changes of serum 25(OH) D3 and IGF-1 levels in patients with thyroid nodules
The incidence of thyroid nodules in association with quartiles of serum 25(OH)D3 level. Note: Compared with subjects in the first quartile, a decrease of incidence of thyroid nodules was observed in the second, third, and the fourth quartiles (P = 0.083, P = 0.030, and P < 0.001). *P < 0.05, compared with subjects in the first quartile