Cervical intraepithelial neoplasia (CIN) may, at times, unpredictably progress to invasive
carcinoma of the cervix. Epidemiological nutritional studies suggest that higher dietary consumption and circulating levels of certain
micronutrients may be protective against
cervical cancer. However, a preventive role of dietary
antioxidants in CIN is not well established. The purpose of this cross-sectional study was to investigate the comparative plasma concentrations of three potent
antioxidants,
coenzyme Q(10,)
alpha-tocopherol and
gamma-tocopherol, in women with normal Pap smears and patients with a biopsy-confirmed histopathological lesion diagnosed as CIN or
cervical cancer. Plasma concentrations of
coenzyme Q(10,)
alpha-tocopherol and
gamma-tocopherol were measured by high-pressure liquid chromatography in both normal women without any history of abnormal Pap smears (n=48), and patients with histopathologically confirmed diagnoses of: (a) CIN I, n=98; (b) CIN II, n=49; (c) CIN III, n=10; and (d)
cervical cancer, n=25. The mean plasma levels of
coenzyme Q(10),
alpha-tocopherol and
gamma-tocopherol were significantly lower (P<0.001,<0.001, and<0.001, respectively by Kruskal-Wallis test) in patients with various grades of CIN and
cervical cancer compared with controls. After controlling for age and smoking, an inverse association between histological grades of epithelial lesions and both plasma
coenzyme Q(10) and
alpha-tocopherol concentrations was observed. The low plasma concentrations of
coenzyme Q(10) may be due to deficient dietary intake or a decrease in endogenous
coenzyme Q(10) biosynthesis that may reflect increased utilization as a result of
free radical reactive oxygen species induced oxidative stress. Further molecular studies on the mechanistic role of
antioxidants in women with precancer cervical lesions are needed.