André Nkondjock

Coffee consumption and the risk of cancer: an overview.

Habitual coffee drinking has been associated with a reduced risk of mortality and chronic diseases, including cancer. The favourable influence of coffee is supported by several plausible mechanisms due to the presence of a variety of biological compounds such as caffeine, diterpenes, caffeic acid, polyphenols as well as volatile aroma and heterocyclic substances. Current evidence suggests that coffee consumption is associated with a reduced risk of liver, kidney, and to a lesser extent, premenopausal breast and colorectal cancers, while it is unrelated to prostate, pancreas and ovary cancers. Coffee drinking may still help reduce death due to liver cancer.

Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high‐risk women who carry BRCA mutations. We performed a matched case‐control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self‐administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1–3, 4–5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72–1.12), 0.75 (95% CI 0.47–1.19) and 0.31 (95% CI 0.13–0.71; p‐trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.

Dietary patterns and risk of pancreatic cancer

To investigate associations between broad dietary patterns and pancreatic cancer risk, we conducted a case‐control study of 585 histologically confirmed pancreatic cancer cases and 4,779 population‐based controls in 8 Canadian provinces between 1994 and 1997. Dietary intake was assessed using a FFQ. Major dietary patterns were identified by factor analysis. Unconditional logistic regression was used to describe associations between dietary pattern scores and risk of pancreatic cancer. Three dietary patterns were identified: Western, characterized by high intake of processed meats, sweets and desserts, refined grains and potatoes; fruits and vegetables, characterized by high intake of fresh fruits and cruciferous vegetables; drinker, characterized by high consumption of liquor, wine and beer. After adjustment for age, BMI, smoking, physical activity, province, educational attainment and total energy intake, the fruits and vegetables pattern was associated with a 49% reduction in pancreatic risk among men (OR = 0.51, 95% CI 0.29–0.90, p = 0.004) when comparing the highest and lowest quartiles of dietary pattern scores. No significant relationship was observed with the Western and drinker patterns. Although the response rate for eligible, recruited subjects was relatively low, our results suggest that the fruits and vegetables dietary pattern reduces pancreatic cancer risk among men.

Dietary carotenoids and risk of colon cancer: Case-control study

Some epidemiological studies suggest that consumption of fruits and vegetables with a high carotenoid content may protect against colon cancer (CC). The evidence, however, is not completely consistent. Given the inconsistencies in findings in previous studies and continued interest in identifying modifiable risk factors for CC, a case‐control study of French‐Canadian in Montreal, Canada, was undertaken to examine the possible association between dietary carotenoids and CC risk and to investigate whether this association varies in relation to lifestyle factors such as smoking or diet, and particularly the high consumption of long‐chain polyunsaturated fatty acids (LCPUFA). A total of 402 colorectal cases (200 males and 202 females) and 688 population‐based controls matched for age, gender and place of residence were interviewed. Dietary intake was assessed through a validated food frequency questionnaire that collected information on over 200 food items and recipes. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in unconditional logistic regression models. After adjustment for important variables such as total energy intake, no association was found between dietary intake of carotenoids and CC risk. For women with high intakes of LCPUFA, an inverse association was found between lutein + zeaxanthin and CC risk. ORs were 0.41; 95%CI (0.19–0.91), p=0.03 for eicosapentaenoic acid, and OR=0.36, 95%CI (0.19–0.78), p=0.01 for docosahexaenoic acid, when the upper quartiles of intake were compared to the lower. Among never‐smokers, a significantly reduced risk of CC was associated with intake of β‐carotene [OR=0.44, 95%CI (0.21–0.92) and p=0.02], whereas an inverse association was found between lycopene intake and CC risk [OR=0.63, 95%CI (0.40–0.98) and p=0.05] among smokers. The results of our study suggest that a diet rich in both lutein + zeaxanthin and LCPUFAs may help prevent CC in French‐Canadian females.

Consumption of Food Groups and the Risk of Pancreatic Cancer: A Case–Control Study

PurposeThe purpose of this study is to investigate whether the consumption of specific food groups predicts the risk of pancreatic cancer, a case–control study of nutrition and pancreatic cancer among French-Canadians was carried out in Montreal, Quebec, Canada.MethodsA total of 179 pancreatic cancer cases (97 males and 82 females) and 239 population-based control subjects were interviewed. Dietary intake was evaluated via a validated food frequency questionnaire that gathers information on over 200 different food items and beverages. Odd ratios (ORs) and 95% confidence intervals (CIs) were computed by unconditional logistic regression.ResultsAfter adjustment for age, smoking, diabetes status, proxy interview, gender and total energy intake, a reduced risk of pancreatic cancer was related to vegetables and vegetable products [OR = 0.47; 95%CI: (0.21–1.06) p-trend = 0.024], while an increased risk was associated with the consumption of lamb, veal and game [OR = 2.24; 95%CI: (1.11–4.52) p-trend = 0.026], when the upper and lower quartiles of intake were compared. Changes in dietary intake over the last decade revealed an elevated risk with augmented consumption of soups, sauces and gravies [OR = 2.32; 95%CI: (1.20–4.49) p-trend=0.03], beef products [OR = 2.07; 95%CI: (0.95–4.51) p-trend=0.05] as well as fish and shellfish [OR = 1.48; 95%CI: (0.78–2.80) p-trend=0.05].ConclusionsThese findings suggest that a diet rich in vegetables and vegetable products may decrease the risk of pancreatic cancer.