Miriam Calligaro

OBJECTIVE: To examine the association between serum concentrations of total cholesterol, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol, triglycerides, apolipoprotein A-I (apoA), apolipoprotein B and the incidence of colorectal cancer (CRC). DESIGN: Nested case-control study. SETTING: The study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC), a cohort of more than 520,000 participants from 10 western European countries. PARTICIPANTS: 1238 cases of incident CRC, which developed after enrolment into the cohort, were matched with 1238 controls for age, sex, centre, follow-up time, time of blood collection and fasting status. MAIN OUTCOME MEASURES: Serum concentrations were quantitatively determined by colorimetric and turbidimetric methods. Dietary and lifestyle data were obtained from questionnaires. Conditional logistic regression models were used to estimate incidence rate ratios (RRs) and 95% CIs which were adjusted for height, weight, smoking habits, physical activity, education, consumption of fruit, vegetables, meat, fish, alcohol, fibre and energy. RESULTS: After adjustments, the concentrations of HDL and apoA were inversely associated with the risk of colon cancer (RR for 1 SD increase of 16.6 mg/dl in HDL and 32.0 mg/dl in apoA of 0.78 (95% CI 0.68 to 0.89) and 0.82 (95% CI 0.72 to 0.94), respectively). No association was observed with the risk of rectal cancer. Additional adjustment for biomarkers of systemic inflammation, insulin resistance and oxidative stress or exclusion of the first 2 years of follow-up did not influence the association between HDL and risk of colon cancer. CONCLUSIONS: These findings show that high concentrations of serum HDL are associated with a decreased risk of colon cancer. The mechanism behind this association needs further elucidation.

Abstract Background: Blood lipids and lipoproteins may affect colorectal cancer (CRC) risk, but results are inconsistent. We examined the relation between serum levels of total cholesterol, high density lipoprotein (HDL), low density lipoprotein, triglycerides, apo lipoprotein A–I (apoA), apo lipoprotein B and the incidence of CRC. Methods: A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC). A total of 1238 first primary incident colorectal cancer cases were matched to 1238 controls by age, gender, center, time of blood collection and fasting status. Serum levels were quantitatively determined by a colorimetric method. Conditional logistic regression models were used to estimate relative risks (RRs) and 95% confidence intervals (95% CI). Results: After adjustments, levels of HDL and apoA were inversely associated with colon cancer risk (RR for one standard deviation increase of 0.43 mmol/L in HDL and 0.32 g/L in apoA (95% CI) = 0.78 (0.68–0.89); p<0.01 and 0.82 (0.72–0.94); p<0.01, respectively) and with distal cancer risk (0.79 (0.65–0.96); p=0.02 and 0.83 (0.69–1.01); p=0.07, respectively). Although only slightly weaker, associations with proximal colon cancer risk were not statistically significant (0.82 (0.65–1.03); p=0.09 and 0.86 (0.68–1.07); p=0.18, respectively). Inclusion of other biomarkers or exclusion of the first 2 years of follow-up did not influence the association between HDL and colon cancer risk. No association was observed for rectal cancer risk. Conclusion: These findings suggest that high HDL levels may decrease colon cancer risk. The mechanism behind this association should be further investigated. Citation Information: Cancer Prev Res 2010;3(1 Suppl):PR-04.