Dietary vitamin A and lung cancer risk: an analysis by histologic subtypes.

A case-control study was conducted based on 427 white males with lung cancer of the squamous, small cell, and adenocarcinoma histologic subtypes and 1,094 white male controls admitted to Roswell Park Memorial Institute between the years 1957 and 1965. The relation between selected dietary factors and lung cancer risk was examined for each histologic subtype while controlling for past cigarette use. Dietary vitamin A was found to be negatively associated with risk for squamous cell and small cell carcinoma, but not for adenocarcinoma of the lung. No significant association was observed, however, between dietary vitamin C, fats, or fiber and any of the lung cancer subtypes. These results suggest that the apparent protective effect of vitamin A in lung cancer may be histologic type-specific.