Serum vitamin D as a novel biomarker for asymptomatic uterine fibroids: re-evaluating the risk threshold for incident fibroid development.

Objective: Lower serum vitamin D levels are inversely correlated with the risk of uterine fibroids (UFs). The existing vitamin D deficiency cutoffs are defined based on the risk of bone loss instead of asymptomatic fibroids. This study aimed to clarify the relationship between vitamin D deficiency and first-time diagnosed asymptomatic UFs, and identify the optimal threshold for assessing the risk of newly-developed fibroids. Methods: In this case-control study, 171 asymptomatic UFs patients and 125 normal controls aged 34-45 were enrolled. A total of 64 pairs matched by age, BMI, gravity and parity were created. Logistic regression models were used to examine the correlation between vitamin D and the risk of asymptomatic UFs, and the receiver operating characteristic curve was employed to evaluate the diagnostic performance of vitamin D deficiency thresholds for the risk of asymptomatic fibroids. Results: Both in the unmatched and matched groups, serum vitamin D levels of asymptomatic patients were lower than those of normal control individuals [(12.79 ± 5.55 vs. 16.19 ± 4.64, Conclusions: The newly-developed vitamin D deficiency threshold pf 14.34 ng/mL generates a balanced screening efficacy in women at a higher risk of UFs, and provides a possible approach for the secondary prevention strategy of UFs.