Diet and colorectal cancer: results of two case-control studies in Russia.

Two case-control studies of diet and colorectal cancer were conducted in Moscow and Khabarovsk. The Moscow study comprised 100 cases of colorectal cancer and 100 neighbourhood controls. The Khabarovsk study consisted of 117 cases of colorectal cancer and 117 population controls. A history of the usual dietary intake one year prior to interview was taken using a food frequency questionnaire. Effects were adjusted in analysis for energy intake and education. Significantly reduced risks were observed with high intakes of cellulose (P = 0.001), beta-carotene (P = 0.002), vitamin C (P = 0.007), polyunsaturated fatty acids (PUFA) (P = 0.004), cholesterol (P = 0.04), and with a high ratio of PUFA to saturated fatty acids (SFA) (P = 0.002). Significant increases in risk were observed in association with high ratios of intakes of protein to cellulose (P = 0.002) and of fat to cellulose (P = 0.008). High intake of total fat was associated with non-significant decrease in the risk (P = 0.12), while high intake of SFA resulted in statistically non-significant increase in risk (P = 0.40). Significant reductions in risk were associated with high frequencies of consumption of vegetables (P = 0.001) and fruit (P = 0.009). There were results suggestive of a decreased risk with a high frequency of milk consumption (P = 0.06) and an increased risk in association with a ratio of meat to vegetable frequencies (P = 0.09). After adjustment among factors effecting risk of colorectal cancer statistically significant increase in the risk was seen only for protein/cellulose ratio and significant protective effect for PUFA/SFA ratio, beta-carotene and vegetable consumption.