Abstract
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.