R. Kaaks

General and Abdominal Adiposity and Risk of Death in Europe

BACKGROUND Previous studies have relied predominantly on the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) to assess the association of adiposity with the risk of death, but few have examined whether the distribution of body fat contributes to the prediction of death. METHODS We examined the association of BMI, waist circumference, and waist-to-hip ratio with the risk of death among 359,387 participants from nine countries in the European Prospective Investigation into Cancer and Nutrition (EPIC). We used a Cox regression analysis, with age as the time variable, and stratified the models according to study center and age at recruitment, with further adjustment for educational level, smoking status, alcohol consumption, physical activity, and height. RESULTS During a mean follow-up of 9.7 years, 14,723 participants died. The lowest risks of death related to BMI were observed at a BMI of 25.3 for men and 24.3 for women. After adjustment for BMI, waist circumference and waist-to-hip ratio were strongly associated with the risk of death. Relative risks among men and women in the highest quintile of waist circumference were 2.05 (95% confidence interval [CI], 1.80 to 2.33) and 1.78 (95% CI, 1.56 to 2.04), respectively, and in the highest quintile of waist-to-hip ratio, the relative risks were 1.68 (95% CI, 1.53 to 1.84) and 1.51 (95% CI, 1.37 to 1.66), respectively. BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P<0.001). CONCLUSIONS These data suggest that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist-to-hip ratio in addition to BMI in assessing the risk of death.

European prospective investigation into cancer and nutrition (EPIC): study populations and data collection

The European Prospective Investigation into Cancer and Nutrition (EPIC) is an ongoing multi-centre prospective cohort study designed to investigate the relationship between nutrition and cancer, with the potential for studying other diseases as well. The study currently includes 519 978 participants (366 521 women and 153 457 men, mostly aged 35-70 years) in 23 centres located in 10 European countries, to be followed for cancer incidence and cause-specific mortality for several decades. At enrollment, which took place between 1992 and 2000 at each of the different centres, information was collected through a non-dietary questionnaire on lifestyle variables and through a dietary questionnaire addressing usual diet. Anthropometric measurements were performed and blood samples taken, from which plasma, serum, red cells and buffy coat fractions were separated and aliquoted for long-term storage, mostly in liquid nitrogen. To calibrate dietary measurements, a standardised, computer-assisted 24-hour dietary recall was implemented at each centre on stratified random samples of the participants, for a total of 36 900 subjects. EPIC represents the largest single resource available today world-wide for prospective investigations on the aetiology of cancers (and other diseases) that can integrate questionnaire data on lifestyle and diet, biomarkers of diet and of endogenous metabolism (e.g. hormones and growth factors) and genetic polymorphisms. First results of case-control studies nested within the cohort are expected early in 2003. The present paper provides a description of the EPIC study, with the aim of simplifying reference to it in future papers reporting substantive or methodological studies carried out in the EPIC cohort.

Fruit and vegetable intake and type 2 diabetes: EPIC-InterAct prospective study and meta-analysis

Fruit and vegetable intake (FVI) may reduce the risk of type 2 diabetes (T2D), but the epidemiological evidence is inconclusive. The aim of this study is to examine the prospective association of FVI with T2D and conduct an updated meta-analysis. In the European Prospective Investigation into Cancer-InterAct (EPIC-InterAct) prospective case–cohort study nested within eight European countries, a representative sample of 16 154 participants and 12 403 incident cases of T2D were identified from 340 234 individuals with 3.99 million person-years of follow-up. For the meta-analysis we identified prospective studies on FVI and T2D risk by systematic searches of MEDLINE and EMBASE until April 2011. In EPIC-InterAct, estimated FVI by dietary questionnaires varied more than twofold between countries. In adjusted analyses the hazard ratio (95% confidence interval) comparing the highest with lowest quartile of reported intake was 0.90 (0.80–1.01) for FVI; 0.89 (0.76–1.04) for fruit and 0.94 (0.84–1.05) for vegetables. Among FV subtypes, only root vegetables were inversely associated with diabetes 0.87 (0.77–0.99). In meta-analysis using pooled data from five studies including EPIC-InterAct, comparing the highest with lowest category for FVI was associated with a lower relative risk of diabetes (0.93 (0.87–1.00)). Fruit or vegetables separately were not associated with diabetes. Among FV subtypes, only green leafy vegetable (GLV) intake (relative risk: 0.84 (0.74–0.94)) was inversely associated with diabetes. Subtypes of vegetables, such as root vegetables or GLVs may be beneficial for the prevention of diabetes, while total FVI may exert a weaker overall effect.

Long-term weight change and breast cancer risk: the European prospective investigation into cancer and nutrition (EPIC)

We examined prospectively the association between weight change during adulthood and breast cancer risk, using data on 1358 incident cases that developed during 5.8 years of follow-up among 40 429 premenopausal and 57 923 postmenopausal women from six European countries, taking part in the European prospective investigation into cancer and nutrition study. Multivariate Cox regression models were used to calculate hazard ratios according to weight change (kg), defined as the weight difference between age at enrolment and age 20 adjusted for other risk factors. Changes in weight were not associated with premenopausal breast cancer risk. In postmenopausal women, weight gain was positively associated with breast cancer risk only among noncurrent hormone replacement therapy (HRT) users (P-trend ⩽0.0002). Compared to women with a stable weight (±2 kg), the relative risk for women who gained 15–20 kg was 1.50 (95% confidence interval (CI) 1.06–2.13). The pooled RR per weight gain increment of 5 kg was 1.08 (95% CI 1.04–1.12). Weight gain was not associated with breast cancer risk in current HRT users, although, overall, these women experienced a much higher risk of breast cancer compared with nonusers. Our findings suggest that large adult weight gain was a significant predictor of breast cancer in postmenopausal women not taking exogenous hormones.

Mediterranean diet and type 2 diabetes risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study: the InterAct project.

OBJECTIVE To study the association between adherence to the Mediterranean dietary pattern (MDP) and risk of developing type 2 diabetes, across European countries. RESEARCH DESIGN AND METHODS We established a case-cohort study including 11,994 incident type 2 diabetic case subjects and a stratified subcohort of 15,798 participants selected from a total cohort of 340,234 participants with 3.99 million person-years of follow-up, from eight European cohorts participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The relative Mediterranean diet score (rMED) (score range 0–18) was used to assess adherence to MDP on the basis of reported consumption of nine dietary components characteristic of the Mediterranean diet. Cox proportional hazards regression, modified for the case-cohort design, was used to estimate the association between rMED and risk of type 2 diabetes, adjusting for confounders. RESULTS The multiple adjusted hazard ratios of type 2 diabetes among individuals with medium (rMED 7–10 points) and high adherence to MDP (rMED 11–18 points) were 0.93 (95% CI 0.86–1.01) and 0.88 (0.79–0.97), respectively, compared with individuals with low adherence to MDP (0–6 points) (P for trend 0.013). The association between rMED and type 2 diabetes was attenuated in people <50 years of age, in obese participants, and when the alcohol, meat, and olive oil components were excluded from the score. CONCLUSIONS In this large prospective study, adherence to the MDP, as defined by rMED, was associated with a small reduction in the risk of developing type 2 diabetes in this European population.

Sex hormones and risk of breast cancer in premenopausal women: a collaborative reanalysis of individual participant data from seven prospective studies

BACKGROUND Associations between circulating concentrations of oestrogens, progesterone, and androgens with breast cancer and related risk factors in premenopausal women are not well understood. We aimed to characterise these associations with a pooled analysis of data from seven studies. METHODS Individual participant data for prediagnostic sex hormone and sex hormone-binding globulin (SHBG) concentrations were contributed from seven prospective studies. We restricted analyses to women who were premenopausal and younger than 50 years at blood collection, and to women with breast cancer diagnosed before age 50 years. We estimated odds ratios (ORs) with 95% CIs for breast cancer associated with hormone concentrations by conditional logistic regression in cases and controls matched for age, date of blood collection, and day of cycle, with stratification by study and further adjustment for cycle phase. We examined associations of hormones with risk factors for breast cancer in control women by comparing geometric mean hormone concentrations in categories of these risk factors, adjusted for study, age, phase of menstrual cycle, and body-mass index (BMI). All statistical tests were two-sided. FINDINGS We included data for up to 767 women with breast cancer and 1699 controls in the risk analyses. Breast cancer risk was associated with a doubling in concentrations of oestradiol (OR 1·19, 95% CI 1·06-1·35), calculated free oestradiol (1·17, 1·03-1·33), oestrone (1·27, 1·05-1·54), androstenedione (1·30, 1·10-1·55), dehydroepiandrosterone sulphate (1·17, 1·04-1·32), testosterone (1·18, 1·03-1·35), and calculated free testosterone (1·08, 0·97-1·21). Breast cancer risk was not associated with luteal phase progesterone (doubling in concentration OR 1·00, 95% CI 0·92-1·09), and adjustment for other factors had little effect on any of these ORs. Cross-sectional analyses in control women showed several associations of sex hormones with breast cancer risk factors. INTERPRETATION Circulating oestrogens and androgens are positively associated with the risk for breast cancer in premenopausal women.

Components of the metabolic syndrome and colorectal cancer risk : a prospective study

Objective:To examine the relation of well-known factors of the metabolic syndrome (MetS) as well as related circulating factors, with risk of colorectal cancer.Methods:We performed a case control study of 306 colorectal cancer cases and 595 matched controls nested in the Northern Sweden Health and Disease Cohort. Levels of C-peptide, glycated haemoglobin (HbA1c), leptin and adiponectin were measured in cryopreserved samples. Body mass index (BMI), systolic and diastolic blood pressure and fasting and post-load plasma glucose, had been measured in a subcohort. Conditional logistic regression was used to calculate odds ratios (OR) of disease, including risk assessments for the MetS factors: obesity (BMI>30 kg m−2), hypertension (blood pressure ⩾140/90 mmHg or use of anti-hypertensive drugs) and hyperglycaemia (fasting glucose ⩾6.1 mmol l−1 or post-load glucose in capillary plasma ⩾8.9 mmol l−1).Results:None of the studied variables were significantly associated with risk across quartiles. Presence of obesity, hypertension and hyperglycaemia significantly increased the risk of colorectal cancer; OR for three vs null factors was 2.57 (95% Confidence Interval [CI] 1.20–5.52; P trend=0.0021), as compared to a 30 to 70% increased risk for the factors in single. Similarly, top decile levels of C-peptide, HbA1c and leptin/adiponectin ratio were associated with an increased risk; ORs for top vs deciles 1–9 were 1.56 (95% CI 0.93–2.62; P=0.090), 1.83 (95% CI 1.00–3.36; P=0.051) and 1.50 (95% CI 0.83–2.71; P=0.18), respectively.Conclusions:Our study support the view that components of the MetS increase risk of colorectal cancer, and further suggests that only very high levels of metabolic factors confer an increased risk.

Adherence to the mediterranean diet and risk of breast cancer in the European prospective investigation into cancer and nutrition cohort study

Epidemiological evidence suggests that the Mediterranean diet (MD) could reduce the risk of breast cancer (BC). As evidence from the prospective studies remains scarce and conflicting, we investigated the association between adherence to the MD and risk of BC among 335,062 women recruited from 1992 to 2000, in ten European countries, and followed for 11 years on average. Adherence to the MD was estimated through an adapted relative Mediterranean diet (arMED) score excluding alcohol. Cox proportional hazards regression models were used while adjusting for BC risk factors. A total of 9,009 postmenopausal and 1,216 premenopausal first primary incident invasive BC were identified (5,862 estrogen or progesterone receptor positive [ER+/PR+] and 1,018 estrogen and progesterone receptor negative [ER−/PR−]). The arMED was inversely associated with the risk of BC overall and in postmenopausal women (high vs. low arMED score; hazard ratio [HR] = 0.94 [95% confidence interval [CI]: 0.88, 1.00] ptrend = 0.048, and HR = 0.93 [95% CI: 0.87, 0.99] ptrend = 0.037, respectively). The association was more pronounced in ER−/PR− tumors (HR = 0.80 [95% CI: 0.65, 0.99] ptrend = 0.043). The arMED score was not associated with BC in premenopausal women. Our findings show that adherence to a MD excluding alcohol was related to a modest reduced risk of BC in postmenopausal women, and this association was stronger in receptor‐negative tumors. The results support the potential scope for BC prevention through dietary modification.

Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study

Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of circulating IGF-I is bound to an acid-labile subunit and to one of six insulin-like growth factor binding proteins (IGFBPs), among which the most important are IGFBP-3 and IGFBP-1. Polymorphisms of the IGF1 gene and of genes encoding for the major IGF-I carriers may predict circulating levels of IGF-I and have an impact on cancer risk. We tested this hypothesis with a case–control study of 807 breast cancer patients and 1588 matched control subjects, nested within the European Prospective Investigation into Cancer and Nutrition. We genotyped 23 common single nucleotide polymorphisms in IGF1, IGFBP1, IGFBP3 and IGFALS, and measured serum levels of IGF-I and IGFBP-3 in samples of cases and controls. We found a weak but significant association of polymorphisms at the 5′ end of the IGF1 gene with breast cancer risk, particularly among women younger than 55 years, and a strong association of polymorphisms located in the 5′ end of IGFBP3 with circulating levels of IGFBP-3, which confirms previous findings. Common genetic variation in these candidate genes does not play a major role in altering breast cancer risk in Caucasians.

Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women

Objective:The aim of this study was to examine the relationship of diet with serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in women.Design:Cross-sectional study.Setting and subjects:The population are 2109 women who were control subjects in a case–control study of breast cancer nested in the European Prospective Investigation into Cancer and Nutrition. Control subjects were randomly chosen among risk sets consisting of female cohort members alive and free of cancer (except non-melanoma skin cancer) at the time of diagnosis of the index case. Matching criteria were age at enrolment, follow-up time, time of the day of blood collection and study centre. Diet was measured through validated questionnaires. Serum hormone concentrations were measured by enzyme-linked immunosorbent assays. The relationship between serum IGF-I, IGFBP-3, and intake of nutrients and foods was explored by linear regression in models adjusted for energy intake, age, body mass index, smoking, physical activity, centre and laboratory batch.Results:Serum IGF-I levels were positively related to protein intake (P trend<0.001), but not related to energy, fat or carbohydrate intake. Positive relationships were observed with the intake of milk (P trend=0.007), calcium (P trend<0.001), magnesium (P trend=0.003), phosphorus (P trend<0.001), potassium (P trend=0.002), vitamin B6 (P trend=0.03), vitamin B2 (P trend=0.001) and inverse relationships with vegetables (P trend=0.02) and beta-carotene (P trend=0.02). IGFBP-3 was not related with most of the nutrients and foods in this study.Conclusions:In this population, circulating IGF-I is modestly related with the intake of protein and minerals, and with milk and cheese, while IGFBP-3 does not appear to be related with diet.