Genome-wide association studies and Mendelian randomization analyses provide insights into the causes of early-onset colorectal cancer.

BACKGROUND: The incidence of early-onset colorectal cancer (EOCRC; diagnosed <50 years of age) is rising globally; however, the causes underlying this trend are largely unknown. CRC has strong genetic and environmental determinants, yet common genetic variants and causal modifiable risk factors underlying EOCRC are unknown. We conducted the first EOCRC-specific genome-wide association study (GWAS) and Mendelian randomization (MR) analyses to explore germline genetic and causal modifiable risk factors associated with EOCRC. PATIENTS AND METHODS: We conducted a GWAS meta-analysis of 6176 EOCRC cases and 65 829 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colorectal Transdisciplinary Study (CORECT), the Colon Cancer Family Registry (CCFR), and the UK Biobank. We then used the EOCRC GWAS to investigate 28 modifiable risk factors using two-sample MR. RESULTS: We found two novel risk loci for EOCRC at 1p34.1 and 4p15.33, which were not previously associated with CRC risk. We identified a deleterious coding variant (rs36053993, G396D) at polyposis-associated DNA repair gene MUTYH (odds ratio 1.80, 95% confidence interval 1.47-2.22) but show that most of the common genetic susceptibility was from noncoding signals enriched in epigenetic markers present in gastrointestinal tract cells. We identified new EOCRC-susceptibility genes, and in addition to pathways such as transforming growth factor (TGF) ß, suppressor of Mothers Against Decapentaplegic (SMAD), bone morphogenetic protein (BMP) and phosphatidylinositol kinase (PI3K) signaling, our study highlights a role for insulin signaling and immune/infection-related pathways in EOCRC. In our MR analyses, we found novel evidence of probable causal associations for higher levels of body size and metabolic factors-such as body fat percentage, waist circumference, waist-to-hip ratio, basal metabolic rate, and fasting insulin-higher alcohol drinking, and lower education attainment with increased EOCRC risk. CONCLUSIONS: Our novel findings indicate inherited susceptibility to EOCRC and suggest modifiable lifestyle and metabolic targets that could also be used to risk-stratify individuals for personalized screening strategies or other interventions.

Dietary fatty acids and endometrial cancer risk within the European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: Diet may impact important risk factors for endometrial cancer such as obesity and inflammation. However, evidence on the role of specific dietary factors is limited. We investigated associations between dietary fatty acids and endometrial cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: This analysis includes 1,886 incident endometrial cancer cases and 297,432 non-cases. All participants were followed up for a mean of 8.8 years. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of endometrial cancer across quintiles of individual fatty acids estimated from various food sources quantified through food frequency questionnaires in the entire EPIC cohort. The false discovery rate (q-values) was computed to control for multiple comparisons. RESULTS: Consumption of n-6 γ-linolenic acid was inversely associated with endometrial cancer risk (HR comparing 5th with 1st quintileQ5-Q1=0.77, 95% CI = 0.64; 0.92, ptrend=0.01, q-value = 0.15). This association was mainly driven by γ-linolenic acid derived from plant sources (HRper unit increment=0.94, 95%CI= (0.90;0.98), p = 0.01) but not from animal sources (HRper unit increment= 1.00, 95%CI = (0.92; 1.07), p = 0.92). In addition, an inverse association was found between consumption of n-3 α-linolenic acid from vegetable sources and endometrial cancer risk (HRper unit increment= 0.93, 95%CI = (0.87; 0.99), p = 0.04). No significant association was found between any other fatty acids (individual or grouped) and endometrial cancer risk. CONCLUSION: Our results suggest that higher consumption of γ-linolenic acid and α-linoleic acid from plant sources may be associated with lower risk of endometrial cancer.

Plasma metabolite biomarkers of boiled and filtered coffee intake and their association with type 2 diabetes risk.

BACKGROUND: Habitual coffee intake has been associated with a lower risk of developing type 2 diabetes (T2D), but few studies used biomarkers to reflect intake and investigated different coffee brews, that is boiled and filtered, separately. OBJECTIVES: To identify plasma metabolites associated with boiled or filtered coffee intake and to examine their association with T2D risk in Swedish adults. METHODS: In a case-control study nested within the Västerbotten Intervention Programme, baseline plasma samples from 421 case-control pairs and samples from a subset of 149 pairs at a 10-year follow-up were analysed using untargeted LC-MS metabolomics. We identified metabolites associated with food frequency questionnaires (FFQ)-estimated coffee intake and assessed odds ratios of T2D. RESULTS: In total, 24 and 32 metabolites were associated with boiled or filtered coffee intake. We determined robust metabolite panels for highly specific prediction of boiled or filtered coffee. We observed an inverse association between the metabolite panel of filtered coffee and T2D risk. No association with T2D was observed for the panel of boiled coffee intake. Similar results were observed for FFQ-estimated coffee intake. CONCLUSIONS: We identified plasma metabolites specifically associated with boiled or filtered coffee intake, which might be used as selective biomarkers. Our study supports a protective role of habitual intake of filtered coffee on T2D development. The lack of association for boiled coffee intake might be due to the lack of a protective effect of boiled coffee or due to the limited number of boiled coffee consumers in this population, but it warrants further investigation.

Oral contraceptives, reproductive history and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: Oral contraceptive use and reproductive factors may initiate long-term changes to the hormonal milieu and thereby, possibly influence colorectal cancer risk. METHODS: We examined the association of hormonal and reproductive factors with risk of colorectal cancer among 337,802 women in the European Prospective Investigation into Cancer and Nutrition, of whom 1878 developed colorectal cancer. RESULTS: After stratification for center and age, and adjustment for body mass index, smoking, diabetes mellitus, physical activity and alcohol consumption, ever use of oral contraceptives was marginally inversely associated with colorectal cancer risk (hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.83-1.02), although this association was stronger among post-menopausal women (HR, 0.84; 95% CI: 0.74-0.95). Duration of oral contraceptive use and reproductive factors, including age at menarche, age at menopause, type of menopause, ever having an abortion, parity, age at first full-term pregnancy and breastfeeding, were not associated with colorectal cancer risk. CONCLUSION: Our findings provide limited support for a potential inverse association between oral contraceptives and colorectal cancer risk.

Consumption of filtered and boiled coffee and the risk of first acute myocardial infarction; a nested case/referent study.

BACKGROUND AND AIM: In northern Sweden, consumption of both filtered and boiled coffee is common. Boiled coffee, especially popular in rural areas, is known to raise blood lipids, a risk factor for acute myocardial infarction (MI). To our knowledge, only one epidemiological study, a case-control study from Sweden, has investigated boiled coffee in MI, noting an increased risk at high consumption levels in men, and no association in women. The aim of the present nested case-referent study was to relate consumption of filtered and boiled coffee to the risk of first MI. METHODS AND RESULTS: The study subjects were 375 cases (303 men, 72 women) and 1293 matched referents from the population-based Northern Sweden Health and Disease Study. Coffee consumption was assessed by food frequency questionnaire. Risk estimates were calculated by conditional logistic regression. A statistically significant positive association was found between consumption of filtered coffee and MI risk in men [odds ratio for consumption > or = 4 times/day versus < or = 1 time/day 1.73 (95% CI 1.05-2.84)]. In women, a similar association was observed, but for boiled coffee [odds ratio 2.51 (95% CI 1.08-5.86)]. After adjustment for current smoking, postsecondary education, hypertension, and sedentary lifestyle, the results for women were no longer statistically significant. CONCLUSION: Consumption of filtered coffee was positively associated with the risk of a first MI in men. A similar tendency was observed for boiled coffee in women, but the result was not statistically significant in multivariate analysis. Further investigation in a larger study is warranted.

Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function.

OBJECTIVES: To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI). DESIGN: Nested case-referent study with up to 13 years of follow-up. SETTING: The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment. SUBJECTS: A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data. RESULTS: Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations. CONCLUSIONS: In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.

Low folate levels may protect against colorectal cancer.

BACKGROUND AND AIMS: Dietary folate is believed to protect against colorectal cancer (CRC). However, few studies have addressed the role of circulating levels of folate. The aim of this study was to relate prediagnostic plasma folate and homocysteine concentrations and the methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C polymorphisms to the risk of developing CRC. SUBJECTS: Subjects were 226 cases and 437 matched referents from the population based Northern Sweden Health and Disease Cohort. RESULTS: We observed a bell-shaped association between plasma folate concentrations and CRC risk; multivariate odds ratio for middle versus lowest quintile 2.00 (95% confidence interval (CI) 1.13-3.56). In subjects with follow up times greater than the median of 4.2 years however, plasma folate concentrations were strongly positively related to CRC risk; multivariate odds ratio for highest versus lowest quintile 3.87 (95% CI 1.52-9.87; p trend = 0.007). Homocysteine was not associated with CRC risk. Multivariate odds ratios for the MTHFR polymorphisms were, for 677 TT versus CC, 0.41 (95% CI 0.19-0.85; p trend = 0.062), and for 1298 CC versus AA, 1.62 (95% CI 0.94-2.81; p trend = 0.028). Interaction analysis suggested that the result for 1298A>C may have been largely due to linkage disequilibrium with 677C>T. The reduced CRC risk in 677 TT homozygotes was independent of plasma folate status. CONCLUSIONS: Our findings suggest a decreased CRC risk in subjects with low folate status. This possibility of a detrimental component to the role of folate in carcinogenesis could have implications in the ongoing debate in Europe concerning mandatory folate fortification of foods.

Dietary folate intake and breast cancer risk: European prospective investigation into cancer and nutrition.

BACKGROUND: There is limited evidence on the association between dietary folate intake and the risk of breast cancer (BC) by hormone receptor expression in the tumors. We investigated the relationship between dietary folate and BC risk using data from the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: A total of 367993 women age 35 to 70 years were recruited in 10 European countries. During a median follow-up of 11.5 years, 11575 women with BC were identified. Dietary folate intake was estimated from country-specific dietary questionnaires. Cox proportional hazards regression models were used to quantify the association between dietary variables and BC risk. BC tumors were classified by receptor status. Subgroup analyses were performed by menopausal status and alcohol intake. Intake of other B vitamins was considered. All statistical tests were two-sided. RESULTS: A borderline inverse association was observed between dietary folate and BC risk (hazard ratio comparing top vs bottom quintile [HRQ5-Q1] = 0.92, 95% CI = 0.83 to 1.01, P trend = .037). In premenopausal women, we observed a statistically significant trend towards lower risk in estrogen receptor-negative BC (HRQ5-Q1 = 0.66, 95% CI = 0.45 to 0.96, P trend = .042) and progesterone receptor-negative BC (HRQ5-Q1 = 0.70, 95% CI = 0.51 to 0.97, P trend = .021). No associations were found in postmenopausal women. A 14% reduction in BC risk was observed when comparing the highest with the lowest dietary folate tertiles in women having a high (>12 alcoholic drinks/week) alcohol intake (HRT3-T1 = 0.86, 95% CI = 0.75 to 0.98, P interaction = .035). CONCLUSIONS: Higher dietary folate intake may be associated with a lower risk of sex hormone receptor-negative BC in premenopausal women.

Low-carbohydrate, high-protein score and mortality in a northern Swedish population-based cohort.

BACKGROUND/OBJECTIVE: Long-term effects of carbohydrate-restricted diets are unclear. We examined a low-carbohydrate, high-protein (LCHP) score in relation to mortality. SUBJECTS/METHODS: This is a population-based cohort study on adults in the northern Swedish county of Västerbotten. In 37,639 men (1460 deaths) and 39,680 women (923 deaths) from the population-based Västerbotten Intervention Program, deciles of energy-adjusted carbohydrate (descending) and protein (ascending) intake were added to create an LCHP score (2-20 points). Sex-specific hazard ratios (HR) were calculated by Cox regression. RESULTS: Median intakes of carbohydrates, protein and fat in subjects with LCHP scores 2-20 ranged from 61.0% to 38.6%, 11.3% to 19.2% and 26.6% to 41.5% of total energy intake, respectively. High LCHP score (14-20 points) did not predict all-cause mortality compared with low LCHP score (2-8 points), after accounting for saturated fat intake and established risk factors (men: HR for high vs low 1.03 (95% confidence interval (CI) 0.88-1.20), P for continuous = 0.721; women: HR for high vs low 1.10 (95% CI 0.91-1.32), P for continuous = 0.229). For cancer and cardiovascular disease, no clear associations were found. Carbohydrate intake was inversely associated with all-cause mortality, though only statistically significant in women (multivariate HR per decile increase 0.95 (95% CI 0.91-0.99), P = 0.010). CONCLUSION: Our results do not support a clear, general association between LCHP score and mortality. Studies encompassing a wider range of macronutrient consumption may be necessary to detect such an association.

Validity of food frequency questionnaire estimated intakes of folate and other B vitamins in a region without folic acid fortification.

BACKGROUND/OBJECTIVES: B vitamins have been implicated in major chronic diseases but results have been inconsistent. This study evaluated the accuracy of dietary intakes of folate, vitamin B12, riboflavin and vitamin B6 as measured by the Northern Sweden Food Frequency Questionnaire (FFQ) against repeated 24-h recalls (24HR) and plasma levels, taking into consideration the MTHFR 677C>T polymorphism. SUBJECTS/METHODS: B vitamin intakes assessed by a semi-quantitative FFQ designed to measure the intake over the previous year were compared with those from 10 24HR, as well as to plasma levels of folate and vitamin B12, in randomly selected men (n=96) and women (n=99) aged 30-60 years. FFQ-based B-vitamin intakes were also compared with plasma levels of B-vitamins and with MTHFR 677C4T genotype in 878 men, aged 40-61 years. RESULTS: Intakes of vitamins B12 and riboflavin were similar, whereas folate and B6 intakes were 16-27% higher, as estimated by FFQ versus 24HR. Spearman correlation coefficients between the two methods ranged from 0.31 to 0.63 (all P

Dietary intake of the water-soluble vitamins B1, B2, B6, B12 and C in 10 countries in the European Prospective Investigation into Cancer and Nutrition.

OBJECTIVES: To describe the intake of vitamins thiamine (B1), riboflavin (B2), B6 (pyridoxine), B12 (cobalamine) and C (ascorbic acid) and their food sources among 27 centres in 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. METHODS: Between 1995 and 2000, 36 034 persons aged between 35 and 74 years were administered a standardized 24-h dietary recall using a computerized interview software programme (EPIC-SOFT). Intakes of the four B vitamins and vitamin C were estimated using the standardized EPIC Nutrient Database (ENDB). Mean intakes were adjusted for age and weighted by season and day of recall. RESULTS: Intake of B vitamins did not vary considerably between centres, except in the UK health-conscious cohort, in which substantially higher intakes of thiamine and lower intakes of vitamin B12 were reported compared with other centres. Overall, meat was the most important contributor to the B vitamins in all centres except in the UK health-conscious group. Vitamin C showed a clear geographical gradient, with higher intakes in the southern centres as compared with the northern ones; this was more pronounced in men than in women. Vegetables and fruits were major contributors to vitamin C in all centres, but juices and potatoes were also important sources in the northern centres. CONCLUSIONS: This study showed no major differences across centres in the mean intakes of B vitamins (thiamine, riboflavin, B6, B12), whereas a tendency towards a north-south gradient was observed for vitamin C.

Eating out of home: energy, macro- and micronutrient intakes in 10 European countries. The European Prospective Investigation into Cancer and Nutrition.

OBJECTIVES: To assess the contribution of out-of-home (OH) energy and nutrient intake to total dietary intake, and to compare out- versus in-home nutrient patterns among 27 centres in 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. METHODS: Between 1995 and 2000, 36,034 participants aged between 35-74 years completed a standardized 24-h dietary recall using a software programme (EPIC-Soft) that recorded the place of food/drink consumption. Eating OH was defined as the consumption of foods and beverages anywhere other than in household premises, irrespective of the place of purchase/preparation. Nutrient intakes were estimated using a standardized nutrient database. Mean intakes were adjusted for age and weighted by season and day of recall. RESULTS: Among women, OH eating contributed more to total fat intake than to intakes of protein and carbohydrates. Among both genders, and particularly in southern Europe, OH eating contributed more to sugar and starch intakes and less to total fibre intake. The contribution of OH eating was also lower for calcium and vitamin C intakes. The composition of diet at home was different from that consumed out of home in southern countries, but was relatively similar in the north. CONCLUSIONS: In northern Europe, OH and in-home eating are homogeneous, whereas southern Europeans consider OH eating as a distinctive occasion. In most centres, women selected more fat-rich items when eating out.

The reduced folate carrier (RFC1) 80G > A and folate hydrolase 1 (FOLH1) 1561C > T polymorphisms and the risk of colorectal cancer: a nested case-referent study.

OBJECTIVE: Polymorphisms in genes involved in folate uptake and metabolism may affect folate status and, thereby, the risk of cancer. In this nested case-referent study, we related two such polymorphisms, reduced folate carrier (RFC1) 80G > A and folate hydrolase 1 (FOLH1) 1561C > T, to the risk of colorectal cancer, taking into account pre-diagnostic plasma folate and total homocysteine concentrations and the MTHFR 677C > T polymorphism, which were analysed in a previous study. MATERIAL AND METHODS: Subjects were 220 cases and 414 matched referents from the population-based Northern Sweden Health and Disease Study. RESULTS: The RFC1 80A-allele was associated with reduced plasma folate and elevated plasma total homocysteine concentrations, but the result was statistically significant only for folate. In contrast, the FOLH1 1561T-allele was associated with higher plasma folate and reduced plasma total homocysteine concentrations, and the result was statistically significant only for homocysteine. Neither polymorphism was related to the risk of colorectal cancer, either in univariate analysis or after adjusting for body mass index, current smoking, recreational and occupational physical activity and alcohol intake. Further adjustment for folate or homocysteine status or the MTHFR 677C > T polymorphism did not affect risk estimates. Subjects with the RFC1 80AA genotype in combination with low plasma folate concentrations or the MTHFR 677TT genotype had a reduced risk of colorectal cancer of borderline statistical significance. CONCLUSIONS: These findings suggest that although the RFC1 80G > A and FOLH1 1561C > T polymorphisms may influence folate status, they are not likely to have a major independent role in the development of colorectal cancer.

Patient-centred care--preanalytical factors demand attention: a questionnaire study of venous blood sampling and specimen handling.

OBJECTIVE: Most mistakes in laboratory medicine are the result of human error occurring before the blood sample reaches the laboratory. This survey of preanalytical procedures was designed to identify sources of error and potential targets for quality improvement strategies. MATERIAL AND METHODS: The staff in a highly specialized surgical ward at a university hospital completed a questionnaire addressing the collection and handling of venous blood samples in plastic vacuum test-tubes for general clinical chemistry testing. RESULTS: The results suggest that venous blood sampling instructions are not always followed. When uncertain about how a sample should be collected, the majority of respondents rely on potentially poor sources of information, such as out-of-date printed instructions or the advice of a colleague, rather than consult up-to-date electronic instructions. Furthermore, they do not always report errors and the referrals are not always handled according to sampling instructions. The respondents were highly motivated, however, and had a strong interest in receiving further education in, and assuming increased responsibility for, venous blood sampling procedures in the ward. CONCLUSIONS: We believe that the introduction of standardized routines and regular staff training, combined with an exchange of the existing paper-based referral management system with an electronic system for managing referrals, could increase safety in the preanalytical process, with positive effects on patient safety. Given the importance of venous blood samples in patient care, a more extensive study covering other hospital wards and primary health-care centres is needed.

Modified Mediterranean diet and survival after myocardial infarction: the EPIC-Elderly study.

Mediterranean diet is associated with lower incidence of coronary heart disease, and two randomised trials indicated that it improves prognosis of coronary patients. These trials, however, relied on a total of 100 deaths and evaluated designer diets in the clinical context. We have evaluated the association of adherence to the modified Mediterranean diet, in which unsaturates were substituted for monounsaturates, with survival among elderly with previous myocardial infarction within the European Prospective Investigation into Cancer and nutrition (EPIC) study. As of December 2003, after a median follow-up of 6.7 years, 2671 EPIC participants from nine countries were 60 years or older and had prevalent myocardial infarction but no stroke or cancer at enrolment, complete information on dietary intakes and important covariates and known survival status. Adherence to the modified Mediterranean diet was assessed through a 10-unit-scale. Mortality ratio in relation to modified Mediterranean diet was estimated through Cox regression controlling for possible confounding. Increased adherence to modified Mediterranean diet by two units was associated with 18% lower overall mortality rate (95% confidence interval 7-27%, fixed effects model). There was no significant heterogeneity by sex, age at enrolment, or country, although the association tended to be less evident among northern Europeans. Associations between food groups contributing to the modified Mediterranean diet and mortality were generally weak. A diet inspired by the Mediterranean pattern that can be easily adopted by Western populations is associated with substantial reduction of total mortality of coronary patients in the community.