Geertruida J. van Woudenbergh

Differences in the prospective association between individual plasma phospholipid saturated fatty acids and incident type 2 diabetes: the EPIC-InterAct case-cohort study

Summary Background Conflicting evidence exists regarding the association between saturated fatty acids (SFAs) and type 2 diabetes. In this longitudinal case-cohort study, we aimed to investigate the prospective associations between objectively measured individual plasma phospholipid SFAs and incident type 2 diabetes in EPIC-InterAct participants. Methods The EPIC-InterAct case-cohort study includes 12 403 people with incident type 2 diabetes and a representative subcohort of 16 154 individuals who were selected from a cohort of 340 234 European participants with 3·99 million person-years of follow-up (the EPIC study). Incident type 2 diabetes was ascertained until Dec 31, 2007, by a review of several sources of evidence. Gas chromatography was used to measure the distribution of fatty acids in plasma phospholipids (mol%); samples from people with type 2 diabetes and subcohort participants were processed in a random order by centre, and laboratory staff were masked to participant characteristics. We estimated country-specific hazard ratios (HRs) for associations per SD of each SFA with incident type 2 diabetes using Prentice-weighted Cox regression, which is weighted for case-cohort sampling, and pooled our findings using random-effects meta-analysis. Findings SFAs accounted for 46% of total plasma phospholipid fatty acids. In adjusted analyses, different individual SFAs were associated with incident type 2 diabetes in opposing directions. Even-chain SFAs that were measured (14:0 [myristic acid], 16:0 [palmitic acid], and 18:0 [stearic acid]) were positively associated with incident type 2 diabetes (HR [95% CI] per SD difference: myristic acid 1·15 [95% CI 1·09–1·22], palmitic acid 1·26 [1·15–1·37], and stearic acid 1·06 [1·00–1·13]). By contrast, measured odd-chain SFAs (15:0 [pentadecanoic acid] and 17:0 [heptadecanoic acid]) were inversely associated with incident type 2 diabetes (HR [95% CI] per 1 SD difference: 0·79 [0·73–0·85] for pentadecanoic acid and 0·67 [0·63–0·71] for heptadecanoic acid), as were measured longer-chain SFAs (20:0 [arachidic acid], 22:0 [behenic acid], 23:0 [tricosanoic acid], and 24:0 [lignoceric acid]), with HRs ranging from 0·72 to 0·81 (95% CIs ranging between 0·61 and 0·92). Our findings were robust to a range of sensitivity analyses. Interpretation Different individual plasma phospholipid SFAs were associated with incident type 2 diabetes in opposite directions, which suggests that SFAs are not homogeneous in their effects. Our findings emphasise the importance of the recognition of subtypes of these fatty acids. An improved understanding of differences in sources of individual SFAs from dietary intake versus endogenous metabolism is needed. Funding EU FP6 programme, Medical Research Council Epidemiology Unit, Medical Research Council Human Nutrition Research, and Cambridge Lipidomics Biomarker Research Initiative.

Dietary Intakes of Individual Flavanols and Flavonols Are Inversely Associated with Incident Type 2 Diabetes in European Populations

Dietary flavanols and flavonols, flavonoid subclasses, have been recently associated with a lower risk of type 2 diabetes (T2D) in Europe. Even within the same subclass, flavonoids may differ considerably in bioavailability and bioactivity. We aimed to examine the association between individual flavanol and flavonol intakes and risk of developing T2D across European countries. The European Prospective Investigation into Cancer and Nutrition (EPIC)–InterAct case-cohort study was conducted in 8 European countries across 26 study centers with 340,234 participants contributing 3.99 million person-years of follow-up, among whom 12,403 incident T2D cases were ascertained and a center-stratified subcohort of 16,154 individuals was defined. We estimated flavonoid intake at baseline from validated dietary questionnaires using a database developed from Phenol-Explorer and USDA databases. We used country-specific Prentice-weighted Cox regression models and random-effects meta-analysis methods to estimate HRs. Among the flavanol subclass, we observed significant inverse trends between intakes of all individual flavan-3-ol monomers and risk of T2D in multivariable models (all P-trend < 0.05). We also observed significant trends for the intakes of proanthocyanidin dimers (HR for the highest vs. the lowest quintile: 0.81; 95% CI: 0.71, 0.92; P-trend = 0.003) and trimers (HR: 0.91; 95% CI: 0.80, 1.04; P-trend = 0.07) but not for proanthocyanidins with a greater polymerization degree. Among the flavonol subclass, myricetin (HR: 0.77; 95% CI: 0.64, 0.93; P-trend = 0.001) was associated with a lower incidence of T2D. This large and heterogeneous European study showed inverse associations between all individual flavan-3-ol monomers, proanthocyanidins with a low polymerization degree, and the flavonol myricetin and incident T2D. These results suggest that individual flavonoids have different roles in the etiology of T2D.

The prospective association between total and type of fish intake and type 2 diabetes in 8 European countries: EPIC-InterAct Study

Background: Epidemiologic evidence of an association between fish intake and type 2 diabetes (T2D) is inconsistent and unresolved. Objective: The objective was to examine the association between total and type of fish intake and T2D in 8 European countries. Design: This was a case-cohort study, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) study, with 3.99 million person-years of follow-up, 12,403 incident diabetes cases, and a random subcohort of 16,835 individuals from 8 European countries. Habitual fish intake (lean fish, fatty fish, total fish, shellfish, and combined fish and shellfish) was assessed by country-specific dietary questionnaires. HRs were estimated in each country by using Prentice-weighted Cox regression models and pooled by using a random-effects meta-analysis. Results: No overall association was found between combined fish and shellfish intake and incident T2D per quartile (adjusted HR: 1.00; 95% CI: 0.94, 1.06; P-trend = 0.99). Total fish, lean fish, and shellfish intakes separately were also not associated with T2D, but fatty fish intake was weakly inversely associated with T2D: adjusted HR per quartile 0.97 (0.94, 1.00), with an HR of 0.84 (0.70, 1.01), 0.85 (0.76, 0.95), and 0.87 (0.78, 0.97) for a comparison of the second, third, and fourth quartiles with the lowest quartile of intake, respectively (P-trend = 0.06). Conclusions: These findings suggest that lean fish, total fish, and shellfish intakes are not associated with incident diabetes but that fatty fish intake may be weakly inversely associated. Replication of these findings in other populations and investigation of the mechanisms underlying these associations are warranted. Meanwhile, current public health recommendations on fish intake should remain unchanged.

Meat Consumption and Its Association With C-Reactive Protein and Incident Type 2 Diabetes The Rotterdam Study

OBJECTIVE To investigate whether intake of different types of meat is associated with circulating C-reactive protein (CRP) and risk of type 2 diabetes in a prospective cohort study. RESEARCH DESIGN AND METHODS Our analysis included 4,366 Dutch participants who did not have diabetes at baseline. During a median follow-up period of 12.4 years, 456 diabetes cases were confirmed. Intake of red meat, processed meat, and poultry was derived from a food frequency questionnaire, and their association with serum high-sensitivity CRP was examined cross-sectionally using linear regression models. Their association with risk of type 2 diabetes was examined using multivariate Cox proportional hazards model, including age, sex, family history of diabetes, and lifestyle and dietary factors. RESULTS An increment of 50 g of processed meat was associated with increased CRP concentration (βprocessed meat = 0.12; P = 0.01), whereas intake of red meat and poultry was not. When comparing the highest to the lowest category of meat intake with respect to diabetes incidence, the adjusted relative risks were as follows: for red meat (1.42 [95% CI 1.06–1.91]), for processed meat (1.87 [1.26–2.78]), and for poultry (0.95 [0.74–1.22]). Additional analysis showed that the associations were not affected appreciably after inclusion of CRP into the model. After adjustment for BMI, however, the association for red meat attenuated to 1.18 (0.88–1.59). CONCLUSIONS Intake of processed meat is associated with higher risk of type 2 diabetes. It appears unlikely that CRP mediates this association.

Glycemic index and glycemic load and their association with C-reactive protein and incident type 2 diabetes.

Objective. To investigate whether the Glycemic Index (GI) or Glycemic Load (GL) of a diet is associated with C-reactive Protein (CRP) and risk of type 2 diabetes in a prospective study. Materials and Methods. Our analysis included 4,366 participants who did not have diabetes at baseline. During follow-up 456 diabetes cases were confirmed. Dietary GI and GL were derived from a food-frequency questionnaire and its association with CRP was examined cross-sectionally using linear regression models. The association of GI and GL with diabetes incidence was examined using Cox proportional hazard models. Results. GL, but not GI, was associated with lnCRP at baseline (b GL = 0.11 per 50 units; P = .01). When comparing the highest to the lowest tertile of GI with respect to diabetes incidence, a Relative Risk (RR) of 0.95 [95%CI 0.75, 1.21] was found after adjustment for lifestyle and nutritional factors. For GL the RR for diabetes incidence was 1.00 [95%CI 0.74, 1.36]. Additional adjustment for CRP did not change RRs. Conclusion. Since GI was not associated with CRP and risk of type 2 diabetes, it is unlikely that a high GI diet induces the previously shown positive association between CRP and risk of type 2 diabetes by increasing CRP concentrations.

Adapted dietary inflammatory index and its association with a summary score for low-grade inflammation and markers of glucose metabolism: the Cohort study on Diabetes and Atherosclerosis Maastricht (CODAM) and the Hoorn study

BACKGROUND Diet may be associated with the development of type 2 diabetes through its effects on low-grade inflammation. OBJECTIVES We investigated whether an adapted dietary inflammatory index (ADII) is associated with a summary score for low-grade inflammation and markers of glucose metabolism. In addition, we investigated the mediating role of inflammation in the association between ADII and markers of glucose metabolism. DESIGN We performed cross-sectional analyses of 2 Dutch cohort studies (n= 1024). An ADII was obtained by multiplying standardized energy-adjusted intakes of dietary components by literature-based dietary inflammatory weights that reflected the inflammatory potential of components. Subsequently, these multiplications were summed. Six biomarkers of inflammation were compiled in a summary score. Associations of the ADII (expressed per SD) with the summary score for inflammation and markers of glucose metabolism were investigated by using multiple linear regression models. Inflammation was considered a potential mediator in the analysis with markers of glucose metabolism. RESULTS A higher ADII was associated with a higher summary score for inflammation [β-adjusted = 0.04 per SD (95% CI: 0.01, 0.07 per SD)]. The ADII was also adversely associated with insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR): β-adjusted = 3.5% per SD (95% CI: 0.6%, 6.3% per SD)]. This association was attenuated after the inclusion of the summary score for inflammation [β-adjusted+inflammation = 2.2% (95% CI: -0.6%, 5.0%)]. The ADII was also adversely associated with fasting glucose and postload glucose but not with glycated hemoglobin. CONCLUSION The significant mediating role of low-grade inflammation in the association between the ADII and HOMA-IR suggests that inflammation might be one of the pathways through which diet affects insulin resistance.

Tea consumption and incidence of type 2 diabetes in Europe: the EPIC-InterAct case-cohort study

Background In previous meta-analyses, tea consumption has been associated with lower incidence of type 2 diabetes. It is unclear, however, if tea is associated inversely over the entire range of intake. Therefore, we investigated the association between tea consumption and incidence of type 2 diabetes in a European population. Methodology/Principal Findings The EPIC-InterAct case-cohort study was conducted in 26 centers in 8 European countries and consists of a total of 12,403 incident type 2 diabetes cases and a stratified subcohort of 16,835 individuals from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Country-specific Hazard Ratios (HR) for incidence of type 2 diabetes were obtained after adjustment for lifestyle and dietary factors using a Cox regression adapted for a case-cohort design. Subsequently, country-specific HR were combined using a random effects meta-analysis. Tea consumption was studied as categorical variable (0, >0-<1, 1-<4, ≥4 cups/day). The dose-response of the association was further explored by restricted cubic spline regression. Country specific medians of tea consumption ranged from 0 cups/day in Spain to 4 cups/day in United Kingdom. Tea consumption was associated inversely with incidence of type 2 diabetes; the HR was 0.84 [95%CI 0.71, 1.00] when participants who drank ≥4 cups of tea per day were compared with non-drinkers (p linear trend = 0.04). Incidence of type 2 diabetes already tended to be lower with tea consumption of 1-<4 cups/day (HR = 0.93 [95%CI 0.81, 1.05]). Spline regression did not suggest a non-linear association (pnon-linearity = 0.20). Conclusions/Significance A linear inverse association was observed between tea consumption and incidence of type 2 diabetes. People who drink at least 4 cups of tea per day may have a 16% lower risk of developing type 2 diabetes than non-tea drinkers.

Coffee consumption and coronary calcification: the Rotterdam Coronary Calcification Study.

Background—The role of coffee in the cardiovascular system is not yet clear. We examined the relation of coffee intake with coronary calcification in a population-based cohort. Methods and Results—The study involved 1570 older men and women without coronary heart disease who participated in the Rotterdam Study. Coffee intake was assessed with a semiquantitative food frequency questionnaire. Coronary calcification was detected with electron beam computed tomography. Severe calcification was defined as an Agatson calcium score >400. Sex-specific odds ratios (ORs) with 95% confidence intervals (95% CI) were obtained by logistic regression with adjustment for age, smoking, body mass index, education, and intake of energy and alcohol. In multivariable analysis, coronary calcification in women was significantly reduced for moderate (>3 to 4 cups) and high (>4 cups) coffee intake, compared with a daily intake of 3 cups or less (OR of 0.41 [95% CI: 0.25 to 0.65] and 0.54 [0.33 to 0.87], respectively). The association persisted after additional adjustment for tea and other dietary confounders, and was not modified by smoking. A nonsignificant inverse relationship was also found in men who smoked, whereas in nonsmoking men a direct association was observed. Conclusion—The present study suggests a beneficial effect of coffee drinking against coronary calcification, particularly in women. More research is needed to confirm these findings and to clarify possible effect modification by gender and smoking.

The Association between Dietary Energy Density and Type 2 Diabetes in Europe: Results from the EPIC-InterAct Study

Background Observational studies implicate higher dietary energy density (DED) as a potential risk factor for weight gain and obesity. It has been hypothesized that DED may also be associated with risk of type 2 diabetes (T2D), but limited evidence exists. Therefore, we investigated the association between DED and risk of T2D in a large prospective study with heterogeneity of dietary intake. Methodology/Principal Findings A case-cohort study was nested within the European Prospective Investigation into Cancer (EPIC) study of 340,234 participants contributing 3.99 million person years of follow-up, identifying 12,403 incident diabetes cases and a random subcohort of 16,835 individuals from 8 European countries. DED was calculated as energy (kcal) from foods (except beverages) divided by the weight (gram) of foods estimated from dietary questionnaires. Prentice-weighted Cox proportional hazard regression models were fitted by country. Risk estimates were pooled by random effects meta-analysis and heterogeneity was evaluated. Estimated mean (sd) DED was 1.5 (0.3) kcal/g among cases and subcohort members, varying across countries (range 1.4–1.7 kcal/g). After adjustment for age, sex, smoking, physical activity, alcohol intake, energy intake from beverages and misreporting of dietary intake, no association was observed between DED and T2D (HR 1.02 (95% CI: 0.93–1.13), which was consistent across countries (I 2 = 2.9%). Conclusions/Significance In this large European case-cohort study no association between DED of solid and semi-solid foods and risk of T2D was observed. However, despite the fact that there currently is no conclusive evidence for an association between DED and T2DM risk, choosing low energy dense foods should be promoted as they support current WHO recommendations to prevent chronic diseases.

Inflammatory potential of the diet and colorectal tumor risk in persons with Lynch syndrome

Background: Persons with Lynch syndrome (LS) have high lifetime risk of developing colorectal tumors (CRTs) because of a germline mutation in one of their mismatch repair (MMR) genes. An important process in the development of CRTs is inflammation, which has been shown to be modulated by diet.Objective: We aimed to investigate the association between the inflammatory potential of the diet and the risk of CRTs in persons with LS.Design: We used the dietary intake of 457 persons with LS from a prospective cohort study to calculate the adapted dietary inflammatory index (ADII). The ADII was split into tertiles in which the highest tertile reflects the most proinflammatory potential of the diet. Cox proportional hazard models, with robust sandwich variance estimates to adjust for dependency within families, were used to calculate HRs and 95% CIs of CRTs by ADII tertile. HRs were adjusted for age, smoking status, and education level, and number of colonoscopies as a time-dependent variable. A potential effect measure modification was explored by stratifying the results by mutated MMR gene, sex, and a history of CRTs. We performed sensitivity analyses by repeating the analyses in non-nonsteroidal anti-inflammatory drug (NSAID) users (n = 315).Results: During a median follow-up time of 59 mo, 200 participants (43.8%) developed CRTs. No significant association was shown between highest compared with lowest ADII tertiles (HR for highest compared with lowest tertiles: 1.37; 95% CI: 0.80, 2.34). Stratification by mutated MMR gene, sex, and CRT history did not show significantly differential associations (P-interactions ≥ 0.64). In non-NSAID users, an HR of 1.60 (95% CI: 0.88, 2.93) for highest compared with lowest tertiles was shown. No significant effect modification was shown in this group either (P-interactions ≥ 0.24).Conclusion: A proinflammatory potential of the diet does not seem to be significantly associated with CRT risk in persons with LS.