Diet in the etiology of oral and pharyngeal cancer among women from the southern United States.

A case-control interview study involving 227 women in North Carolina with oral cavity or pharyngeal cancer and 405 matched controls showed a protective effect of a usual adult diet high in fruits and vegetables. The relative risks of 0.65 for moderate and 0.52 for high (relative to 1.0 for infrequent) consumption of fruits and vegetables were statistically significant and remained after controlling for demographic characteristics, tobacco and alcohol use, relative weight, and intake of other food groups. Risks were lower with higher bread and cereal intake but higher for those women with the lightest weights, adjusted for height. The inverse associations between oral and pharyngeal cancer and intake of fruits and vegetables and intake of breads and cereals could not be attributed to an association with general nutritional status, since meat and fish consumption was related to an increased risk of oral and pharynx cancer. Moreover, dairy and egg consumption was generally unrelated to cancer risk. The reduction in risk with greater fruit and vegetable consumption is consistent with the hypothesis that vitamin C and/or beta-carotene intake is associated with a reduced risk of oral and pharyngeal cancer.