OBJECTIVETo evaluate the possible effects of folate on cervical carcinogenesis and the interaction of folate and human papillomaviruses 16 (HPV16).

METHODSA hospital-based case-control study was conducted. 111 hospitalized cases who were pathologically diagnosed of having cervical cancer and 111 controls identified with hysteromyoma that frequency-matched to cases on age, birth place and residential area. A 60-item food-frequency questionnaire (FFQ) were administered to estimate the consumption of dietary folate. HPV16 DNA in exfoliated cervical cell and serum folate were detected by special PCR and radioimmunoassay respectively.

RESULTSHPV16 infection rate in cases (61.26%) was significantly higher than that in controls (28.83%), with adjusted OR of 4.95(95% CI:2.49-9.83).The levels of dietary folate in cases (5.00 microg/kcal +/- 0.41 microg/kcal) were significantly lower than that in controls (5.14 microg/kcal +/- 0.35 microg/kcal), but the adjusted OR showing no statistical significance. However, serum folate in cases (1.79 ng/ml +/- 1.42 ng/ml) was significantly lower than that in controls(2.59 ng/ml +/- 2.81 ng/ml),and there were significantly increasing trend in the risk of cervical cancer with reducing level of serum folate (chi-squared trend test of P = 0.000). Meanwhile, low-level of serum folate and HPV16-infection showed significant interaction in the development of cervical cancer, with likelihood ratio test of G = 5.56, P = 0.02.

CONCLUSIONResults indicated that low levels of folate might increase the risk of cervical cancer, and potential synergistic action might exist between low level of serum folate and HPV16 in the development of cervical cancer.