[A nested case-control study on the relationship between red blood cell folate and the prognosis of low-grade cervical intraepithelial neoplasia].

Objective: To evaluate the relationship between red blood cell folate (RBC folate) and the prognosis of low-grade cervical intraepithelial neoplasia (CIN 1). Methods: In the married women cohort established in 2014, 564 women with CIN 1 diagnosed by pathology were recruited. The demographic characteristics and factors of cervical intraepithelial neoplasia were collected. Meanwhile, the infection status of human papillomavirus (HPV) was detected by molecular diversion hybridization, and the level of RBC folate was measured by chemical photoimmunoassay. After 24 months of follow-up, pathological examination was performed again to observe the prognosis of participants. The women with reversal were taken as the control group,and those with continuous and progressive CIN 1 were taken as the case group respectively. The relationship between RBC folate and CIN 1 outcome was evaluated by logistic regression model. Results: 453 women completed the follow-up, aged (49.72±6.84) years old. CIN 1 was reversed in 342 women, continued in 58 cases and progressed in 53 cases. The RBC folate level M (Q1,Q3) were 399.01 (307.10, 538.97) ng/ml, 316.98 (184.74, 428.49) ng/ml and 247.14 (170.54, 348.97) ng/ml, respectively. With the decrease of RBC folate, the risk of continuous and progressive CIN 1 increased (all P<0.001), while the risk of reversal CIN 1 decreased gradually (P<0.001). Combined with high-risk human papillomavirus (HR-HPV) infection status, low level of RBC folate could increase the risk of CIN 1 progression regardless of HR-HPV infection (HR-HPV infection: OR=21.34, 95%CI: 3.98-114.54; HR-HPV uninfection: OR=11.15, 95%CI: 2.34-53.13). Conclusion: Low level of RBC folate could increase the risk of CIN 1 persistence and progression regardless of HR-HPV infection.