Franck Carbonnel

Animal Protein Intake and Risk of Inflammatory Bowel Disease: The E3N Prospective Study

OBJECTIVES:Diet composition has long been suspected to contribute to inflammatory bowel disease (IBD), but has not been thoroughly assessed, and has been assessed only in retrospective studies that are prone to recall bias. The aim of the present study was to evaluate the role of dietary macronutrients in the etiology of IBD in a large prospective cohort.METHODS:The Etude Épidémiologique des femmes de la Mutuelle Générale de l’Education Nationale cohort consists of women living in France, aged 40–65 years, and free of major diseases at inclusion. A self-administered questionnaire was used to record dietary habits at baseline. Questionnaires on disease occurrence and lifestyle factors were completed every 24 months. IBDs were assessed in each questionnaire until June 2005, and subsequently validated using clinical and pathological criteria. We estimated the association between nutrients or foods and IBD using Cox proportional hazards models adjusted for energy intake.RESULTS:Among 67,581 participants (705,445 person-years, mean follow-up since completion of the baseline dietary questionnaire 10.4 years), we validated 77 incident IBD cases. High total protein intake, specifically animal protein, was associated with a significantly increased risk of IBD, (hazards ratio for the third vs. first tertile and 95% confidence interval being 3.31 and 1.41–7.77 (P trend=0.007), and 3.03 and 1.45–6.34 (P trend=0.005) for total and animal protein, respectively). Among sources of animal protein, high consumption of meat or fish but not of eggs or dairy products was associated with IBD risk.CONCLUSIONS:High protein intake is associated with an increased risk of incident IBD in French middle-aged women.

Abdominal obesity, weight gain during adulthood and risk of liver and biliary tract cancer in a European cohort

General obesity has been positively associated with risk of liver and probably with biliary tract cancer, but little is known about abdominal obesity or weight gain during adulthood. We used multivariable Cox proportional hazard models to investigate associations between weight, body mass index, waist and hip circumference, waist‐to‐hip and waist‐to‐height ratio (WHtR), weight change during adulthood and risk of hepatocellular carcinoma (HCC), intrahepatic (IBDC) and extrahepatic bile duct system cancer [EBDSC including gallbladder cancer (GBC)] among 359,525 men and women in the European Prospective Investigation into Cancer and Nutrition study. Hepatitis B and C virus status was measured in a nested case–control subset. During a mean follow‐up of 8.6 years, 177 cases of HCC, 58 cases of IBDC and 210 cases of EBDSC, including 76 cases of GBC, occurred. All anthropometric measures were positively associated with risk of HCC and GBC. WHtR showed the strongest association with HCC [relative risk (RR) comparing extreme tertiles 3.51, 95% confidence interval (95% CI): 2.09–5.87; ptrend < 0.0001] and with GBC (RR: 1.56, 95% CI: 1.12–2.16 for an increment of one unit in WHtR). Weight gain during adulthood was also positively associated with HCC when comparing extreme tertiles (RR: 2.48, 95% CI: 1.49–4.13; <0.001). No statistically significant association was observed between obesity and risk of IBDC and EBDSC. Our results provide evidence of an association between obesity, particularly abdominal obesity, and risk of HCC and GBC. Our findings support public health recommendations to reduce the prevalence of obesity and weight gain in adulthood for HCC and GBC prevention in Western populations.

LOW EXPOSURE TO SUNLIGHT IS A RISK FACTOR FOR CROHN?S DISEASE

Aliment Pharmacol Ther 2011; 33: 940–945

Diet and risk of inflammatory bowel disease

BACKGROUNDnA better understanding of the environmental factors leading to inflammatory bowel disease should help to prevent occurrence of the disease and its relapses.nnnAIMnTo review current knowledge on dietary risk factors for inflammatory bowel disease.nnnMETHODSnThe PubMed, Medline and Cochrane Library were searched for studies on diet and risk of inflammatory bowel disease.nnnRESULTSnEstablished non-diet risk factors include family predisposition, smoking, appendectomy, and antibiotics. Retrospective case-control studies are encumbered with methodological problems. Prospective studies on European cohorts, mainly including middle-aged adults, suggest that a diet high in protein from meat and fish is associated with a higher risk of inflammatory bowel disease. Intake of the n-6 polyunsaturated fatty acid linoleic acid may confer risk of ulcerative colitis, whereas n-3 polyunsaturated fatty acids may be protective. No effect was found of intake of dietary fibres, sugar, macronutrients, total energy, vitamin C, D, E, Carotene, or Retinol (vitamin A) on risk of ulcerative colitis. No prospective data was found on risk related to intake of fruits, vegetables or food microparticles (titanium dioxide and aluminium silicate).nnnCONCLUSIONSnA diet high in protein, particular animal protein, may be associated with increased risk of inflammatory bowel disease and relapses. N-6 polyunsaturated fatty acids may predispose to ulcerative colitis whilst n-3 polyunsaturated fatty acid may protect. These results should be confirmed in other countries and in younger subjects before dietary counselling is recommended in high risk subjects.

Serological markers predict inflammatory bowel disease years before the diagnosis

Objective Anti-neutrophil cytoplasmic antibodies and anti-Saccharomyces cerevisiae mannan antibodies (ASCAs) have been detected in the serum of patients with ulcerative colitis (UC) and Crohns disease (CD) and their unaffected family members. The aim of this study was to establish the value of serological markers as predictors of UC and CD. Design Individuals who developed CD or UC were identified from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. At recruitment, none of the participants had a diagnosis of CD or UC. For each incident case, two controls were randomly selected matched for centre, date of birth, sex, date of recruitment and time of follow-up. Serum of cases and controls obtained at recruitment were analysed for ASCA IgG, ASCA IgA, perinuclear anti-neutrophil cytoplasmic antibody (pANCA), antibodies against Escherichia coli outer membrane porin C (OmpC) and flagellin CBir1. Conditional logistic regression was used to determine risk of CD and UC. Receiver operating characteristic curves were constructed to test accuracy. Results A total of 77 individuals were diagnosed with CD and 167 with UC after a mean follow-up of 4.5 (SD 3.2) and 4.4 (SD 3.1) years following blood collection, respectively. Combinations of pANCA, ASCA, anti-CBir1 and anti-OmpC were most accurate in predicting incident CD and UC (area under curve 0.679 and 0.657, respectively). The predictive value of the combination of markers increased when time to diagnosis of CD or UC decreased. Conclusion A panel of serological markers is able to predict development of CD and UC in individuals from a low-risk population.

Dietary patterns and risk of inflammatory bowel disease in Europe: Results from the EPIC study

Background:Specific nutrients or foods have been inconsistently associated with ulcerative colitis (UC) or Crohns disease (CD) risks. Thus, we investigated associations between diet as a whole, as dietary patterns, and UC and CD risks. Methods:Within the prospective EPIC (European Prospective Investigation into Cancer) study, we set up a nested matched case–control study among 366,351 participants with inflammatory bowel disease data, including 256 incident cases of UC and 117 of CD, and 4 matched controls per case. Dietary intake was recorded at baseline from validated food frequency questionnaires. Incidence rate ratios of developing UC and CD were calculated for quintiles of the Mediterranean diet score and a posteriori dietary patterns produced by factor analysis. Results:No dietary pattern was associated with either UC or CD risks. However, when excluding cases occurring within the first 2 years after dietary assessment, there was a positive association between a “high sugar and soft drinks” pattern and UC risk (incidence rate ratios for the fifth versus first quintile, 1.68 [1.00–2.82]; Ptrend = 0.02). When considering the foods most associated with the pattern, high consumers of sugar and soft drinks were at higher UC risk only if they had low vegetables intakes. Conclusions:A diet imbalance with high consumption of sugar and soft drinks and low consumption of vegetables was associated with UC risk. Further studies are needed to investigate whether microbiota alterations or other mechanisms mediate this association.

Carbohydrate Intake in the Etiology of Crohn's Disease and Ulcerative Colitis

Background:Diet may have a role in the etiology of inflammatory bowel disease. In previous studies, the associations between increased intakes of carbohydrates, sugar, starch, and inflammatory bowel disease are inconsistent. However, few prospective studies have investigated the associations between these macronutrients and incident Crohns disease (CD) or ulcerative colitis (UC). Methods:A total of 401,326 men and women were recruited between 1991 and 1998. At recruitment, dietary intakes of carbohydrate, sugar, and starch were measured using validated food frequency questionnaires. The cohort was monitored identifying participants who developed incident CD or UC. Cases were matched with 4 controls, and odds ratios were calculated for quintiles of total carbohydrate, sugar, and starch intakes adjusted for total energy intake, body mass index, and smoking. Results:One hundred ten participants developed CD, and 244 participants developed UC during follow-up. The adjusted odds ratio for the highest versus the lowest quintiles of total carbohydrate intake for CD was 0.87, 95% CI = 0.24 to 3.12 and for UC 1.46, 95% CI = 0.62 to 3.46, with no significant trends across quintiles for either (CD, Ptrend = 0.70; UC, Ptrend = 0.41). Similarly, no associations were observed with intakes of total sugar (CD, Ptrend = 0.50; UC, Ptrend = 0.71) or starch (CD, Ptrend = 0.69; UC, Ptrend = 0.17). Conclusions:The lack of associations with these nutrients is in agreement with many case–control studies that have not identified associations with CD or UC. As there is biological plausibility for how specific carbohydrates could have an etiological role in inflammatory bowel disease, future epidemiological work should assess individual carbohydrates, although there does not seem to be a macronutrient effect.

Energy and protein metabolism in malnutrition due to nonneoplastic gastrointestinal diseases

Although a reduction in both energy expenditure and protein turnover has been demonstrated in starved volunteers, few metabolic data are available for patients in whom malnutrition is due to nonneoplastic gastrointestinal diseases. Chronically malnourished, unstressed adult patients with nonneoplastic gastrointestinal diseases (body mass index, 15.8 +/- 2.5 kg/m2, n = 13) and healthy control subjects (n = 10) were studied in the postabsorptive state using indirect calorimetry, as well as substrate fluxes of L[1-13C]leucine, L-[2-15N]glutamine (seven patients and six controls), and D[6,6-2H2]glucose (seven patients and eight controls). Resting energy expenditure (REE) expressed in kilocalories per 24 hours was significantly lower in patients than in controls; REE expressed per unit of fat-free mass (FFM) was not significantly different in both groups. Whole-body leucine turnover, oxidation, and nonoxidative disposal rates, based on either 13C-leucine or 13C-alpha-ketoisocaproic acid (KIC) enrichments, and glucose turnover rate were not significantly different between malnourished patients and controls. Moreover, glutamine turnover was increased by 28% in malnourished patients as compared with normal volunteers (429.8 +/- 86.8 v 334.9 +/- 15.9 mumol/kg/h, P = .02). These results suggest that hypometabolic adaptation, although previously documented in starved volunteers, is not operative during states of chronic malnutrition due to gastrointestinal disease. The increase in glutamine turnover rate might represent an adaptative mechanism to malnutrition for preservation of visceral mass or function.

Dietary intake of iron, heme-iron and magnesium and pancreatic cancer risk in the European prospective investigation into cancer and nutrition cohort

Several studies support a protective effect of dietary magnesium against type 2 diabetes, but a harmful effect for iron. As diabetes has been linked to pancreatic cancer, intake of these nutrients may be also associated with this cancer. We examined the association between dietary intake of magnesium, total iron and heme‐iron and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. In total, 142,203 men and 334,999 women, recruited between 1992 and 2000, were included. After an average follow‐up of 11.3 years, 396 men and 469 women developed exocrine pancreatic cancer. Hazard ratios and 95% confidence intervals (CIs) were obtained using Cox regression stratified by age and center, and adjusted for energy intake, smoking status, height, weight, and self‐reported diabetes status. Neither intake of magnesium, total iron nor heme‐iron was associated with pancreatic cancer risk. In stratified analyses, a borderline inverse association was observed among overweight men (body mass index, ≥25 kg/m2) with magnesium (HRper 100 mg/day increase = 0.79, 95% CI = 0.63–1.01) although this was less apparent using calibrated intake. In female smokers, a higher intake of heme‐iron was associated with a higher pancreatic cancer risk (HR per 1 mg/day increase = 1.38, 95% CI = 1.10–1.74). After calibration, this risk increased significantly to 2.5‐fold (95% CI = 1.22–5.28). Overall, dietary magnesium, total iron and heme‐iron were not associated with pancreatic cancer risk during the follow‐up period. Our observation that heme‐iron was associated with increased pancreatic cancer risk in female smokers warrants replication in additional study populations.

The Association between Glyceraldehyde-Derived Advanced Glycation End-Products and Colorectal Cancer Risk

Background: A large proportion of colorectal cancers are thought to be associated with unhealthy dietary and lifestyle exposures, particularly energy excess, obesity, hyperinsulinemia, and hyperglycemia. It has been suggested that these processes stimulate the production of toxic reactive carbonyls from sugars such as glyceraldehyde. Glyceraldehyde contributes to the production of a group of compounds known as glyceraldehyde-derived advanced glycation end-products (glycer-AGEs), which may promote colorectal cancer through their proinflammatory and pro-oxidative properties. The objective of this study nested within a prospective cohort was to explore the association of circulating glycer-AGEs with risk of colorectal cancer. Methods: A total of 1,055 colorectal cancer cases (colon n = 659; rectal n = 396) were matchced (1:1) to control subjects. Circulating glycer-AGEs were measured by a competitive ELISA. Multivariable conditional logistic regression models were used to calculate ORs and 95% confidence intervals (95% CI), adjusting for potential confounding factors, including smoking, alcohol, physical activity, body mass index, and diabetes status. Results: Elevated glycer-AGEs levels were not associated with colorectal cancer risk (highest vs. lowest quartile, 1.10; 95% CI, 0.82–1.49). Subgroup analyses showed possible divergence by anatomical subsites (OR for colon cancer, 0.83; 95% CI, 0.57–1.22; OR for rectal cancer, 1.90; 95% CI, 1.14–3.19; Pheterogeneity = 0.14). Conclusions: In this prospective study, circulating glycer-AGEs were not associated with risk of colon cancer, but showed a positive association with the risk of rectal cancer. Impact: Further research is needed to clarify the role of toxic products of carbohydrate metabolism and energy excess in colorectal cancer development. Cancer Epidemiol Biomarkers Prev; 24(12); 1855–63. ©2015 AACR.