Nutritional epidemiology of cervical neoplasia

There appears to be a natural progression of some preinvasive cervical lesions to more advanced lesions. Although research has evaluated the associations between nutrients and particular preinvasive lesions or invasive disease, little work has been done to compare results across the spectrum of lesions in the progression to invasive disease. This review compiles studies that have evaluated the relation between nutrients and cervical neoplasia and evaluates the general consistency of the literature across stage of disease. Preformed vitamin A does not appear to be related to risk of any preinvasive or invasive lesions, whereas vitamin C has been associated with a reduced risk for dysplasia, in situ cancer, and invasive disease, particularly among smokers. There was evidence of reduced risks associated with various carotenoids and vitamin E at all stages of the disease process, although these studies were inconsistent and further work is needed. Folate was the only nutrient that appeared to be protective for dysplastic lesions and not related to risk of in situ or invasive disease. Red blood cell folate was a better predictor of dysplasia than were serum or dietary folate, and further investigation using this marker of folate status is warranted. Research is needed across a spectrum of lesions within one study, with particular attention to interactions between nutrients and other risk factors for disease.