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Healthy lifestyle and risk of breast cancer among postmenopausal women in the European Prospective Investigation into Cancer and Nutrition cohort study.
McKenzie, F, Ferrari, P, Freisling, H, Chajès, V, Rinaldi, S, de Batlle, J, Dahm, CC, Overvad, K, Baglietto, L, Dartois, L, et al
International journal of cancer. 2015;136(11):2640-8
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Breast cancer is the most common cancer among women. A number of modifiable lifestyle factors have been shown to be associated with breast cancer risk including diet, physical activity, smoking, alcohol consumption and body fat. A health index combining these five risk factors was created and used to establish an association between lifestyle and breast cancer risk amongst participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) study, a large prospective epidemiological study which recruited 521,330 healthy men and women, including 242,918 postmenopausal women, across Europe. The diet score was based on intakes of seven dietary factors: cereal fibre, folate, the ratio of polyunsaturated to saturated fat, fatty fish (as a marker for omega-3 fatty acids), margarine (as a marker for industrially produced trans-fats), glycaemic load and fruits and vegetables. There was a lower risk of breast cancer in postmenopausal women with healthier lifestyles. All individual components of the healthy lifestyle index were significantly associated with breast cancer risk, except smoking. The combined healthy lifestyle index was overall more strongly associated with breast cancer risk compared to the individual factors. The authors conclude that breast cancer prevention policies should include strategies to engage all women in lasting healthy diet and lifestyle habits.
Abstract
Breast cancer is the most common cancer among women and prevention strategies are needed to reduce incidence worldwide. A healthy lifestyle index score (HLIS) was generated to investigate the joint effect of modifiable lifestyle factors on postmenopausal breast cancer risk. The study included 242,918 postmenopausal women from the multinational European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, with detailed information on diet and lifestyle assessed at baseline. The HLIS was constructed from five factors (diet, physical activity, smoking, alcohol consumption and anthropometry) by assigning scores of 0-4 to categories of each component, for which higher values indicate healthier behaviours. Hazard ratios (HR) were estimated by Cox proportional regression models. During 10.9 years of median follow-up, 7,756 incident breast cancer cases were identified. There was a 3% lower risk of breast cancer per point increase of the HLIS. Breast cancer risk was inversely associated with a high HLIS when fourth versus second (reference) categories were compared [adjusted HR = 0.74; 95% confidence interval (CI): 0.66-0.83]. The fourth versus the second category of the HLIS was associated with a lower risk for hormone receptor double positive (adjusted HR = 0.81, 95% CI: 0.67-0.98) and hormone receptor double negative breast cancer (adjusted HR = 0.60, 95% CI: 0.40-0.90). Findings suggest having a high score on an index of combined healthy behaviours reduces the risk of developing breast cancer among postmenopausal women. Programmes which engage women in long term health behaviours should be supported.
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Serum levels of IGF-I, IGFBP-3 and colorectal cancer risk: results from the EPIC cohort, plus a meta-analysis of prospective studies.
Rinaldi, S, Cleveland, R, Norat, T, Biessy, C, Rohrmann, S, Linseisen, J, Boeing, H, Pischon, T, Panico, S, Agnoli, C, et al
International journal of cancer. 2010;126(7):1702-15
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Insulin-like growth factor-I (IGF-1) plays an important role in growth and development as a function of available energy and essential nutrients from body reserves and diet. The aim of the study was to examine the relationships of colorectal cancers with serum levels of IGF-I, and with 2 measures of IGF-binding protein (IGFBP)-3. The study also examined whether relative risks associated to IGF-I levels were modified by anthropometric and dietary factors. A meta-analysis was performed where the study results were combined with the results from previously published prospective studies. For the study, 1,121 case sets with IGF-1 and total IGFBP-3 measurements were observed. For each case participant with colon or rectum cancer, 1 control participant was selected randomly. Control were matched to cases depending on a set criteria. The study found no association between colorectal cancer risk and serum levels of IGF-1 or IGFBP-3. However, the results from the meta-analysis showed only a very mild significant positive association. Overall, findings from the study together with those from the prospective cohort studies indicate a modest role for elevated circulating IGF-I levels in the development of colorectal cancer.
Abstract
Several prospective studies have shown a moderate positive association between increasing circulating insulin-like growth factor-I (IGF-I) levels and colorectal cancer risk. However, the associations were often statistically nonsignificant, and the relationship of cancer risk with IGF-I's major binding protein, IGFBP-3, showed major discrepancies between studies. We investigated the association of colorectal cancer risk with serum IGF-I, total and intact IGFBP-3, in a case-control study nested within the EPIC cohort (1,121 cases of colorectal cancer and 1,121 matched controls). Conditional logistic regression was used to adjust for possible confounders. Our present study results were combined in a meta-analysis with those from 9 previous prospective studies to examine the overall evidence for a relationship of prediagnostic serum IGF-I with colorectal cancer risk. In the EPIC study, serum concentrations of IGF-I and IGFBP-3 showed no associations with risk of colorectal cancer overall. Only in subgroup analyses did our study show moderate positive associations of IGF-I levels with risk, either among younger participants only (and only for colon cancer) or among participants whose milk intakes were in the lowest tertile of the population distribution (RR for an increase of 100 ng/ml = 1.43 [95% CI = 1.13-1.93]). Nevertheless, in the meta-analysis a modest positive association remained between serum IGF-I and colorectal cancer risk overall (RR = 1.07 [1.01-1.14] for 1 standard deviation increase in IGF-I). Overall, data from our present study and previous prospective studies combined indicate a relatively modest association of colorectal cancer risk with serum IGF-I.