Serum Vitamin D as a novel biomarker for asymptomatic uterine fibroids: Re-evaluating the risk threshold for incident fibroid development

Nenghuan Tang^1,2Haoran Li²Can Luo²LI HU^2,3Chunling Fang^2,3Jie Yu²Fan Xu^3,4*

• ¹Affiliated Hospital of North Sichuan Medical College, Nanchong, China
• ²North Sichuan Medical College, Nanchong, China
• ³Nanchong Central Hospital Affiliated to North Sichuan Medical College, Nanchong, China
• ⁴Shanghai First Maternity and Infant Hospital, Shanghai, China

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, p<0.001) and (11.95±5.27 vs. 17.29±4.99, p<0.001)], and multivariate logistic regression revealed that vitamin D deficiency was related to an increased risk of asymptomatic UFs [(OR=0.81; 95%Cl=0.76-0.87) and (OR=0.79; 95%Cl=0.72-0.87)]. Compared to the widely-used vitamin D deficiency thresholds (12.00 ng/ml, 20.00 ng/ml and 30.00 ng/ml), the new cutoff of 14.34 ng/ml achieved the highest sensitivity and specificity to asymptomatic UFs (sensitivity 70.3%, specificity 76.6%, accuracy:73.4%). 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.