Implications for cancer epidemiology of differences in dietary intake associated with alcohol consumption

Several dietary factors are thought to modify risk for cancers that are known to be associated with alcohol intake. In this study, we sought to identify and describe alcohol-related differences in dietary and nutritional factors that are potential independent predictors of cancer risk or effect modifiers or confounders of alcohol-cancer relationships. Data were obtained from a large hospital-based case-control study that was designed to estimate the cancer risk from various tobacco products. Study subjects consisted of 465 male and 300 female incident lung cancer cases and 870 male and 556 female hospitalized patient controls matched on age (+/- 5 yrs). Nutritional data were analyzed as log-transformed frequencies of 30 food items, 9 factor scores generated to describe overall patterns of dietary intake, and nutrient scores estimating daily intake of fat, vitamin A, fiber, and cholesterol. We observed many more significant differences in nutritional exposures by alcoholic beverage intake than would be expected merely by chance. For males, the most striking relationships included increased meat and egg consumption with increasing alcohol consumption and higher intake of cantaloupe and cold cereal among lighter drinkers. For females, we observed strong inverse relationships between alcohol consumption and reported intake of fruit, cold cereal, and ice cream. We also observed a direct association between alcohol and meat consumption, though it was weaker than that found among men. Findings based on factors and nutrients followed the pattern observed for the individual food items, with highest fat scores and lowest fruit scores among the heaviest drinkers. Implications for nutrient-alcohol interactions and statistical considerations are discussed.