Measures of quality control in the German component of the EPIC study. European Prospective Investigation into Cancer and Nutrition

Reliability estimates for assessing meal timing derived from longitudinal repeated 24-hour dietary recalls

BACKGROUND

Regulating meal timing may have efficacy for improving metabolic health for preventing or managing chronic disease. However, the reliability of measuring meal timing with commonly used dietary assessment tools needs characterization prior to investigating meal timing and health outcomes in epidemiologic studies.

OBJECTIVES

To evaluate the reliability of estimating meal timing parameters, including overnight fasting duration, the midpoint of overnight fasting time, the number of daily eating episodes, the period with the largest percentage of daily caloric intake, and late last eating episode (> 09:00 pm) from repeated 24-h dietary recalls (24HRs).

METHODS

Intraclass correlation coefficients (ICC), Light's Kappa estimates, and 95% CIs were calculated from repeated 24HR administered in 3 epidemiologic studies: The United States-based Interactive Diet and Activity Tracking in AARP (IDATA) study (n = 996, 6 24HR collected over 12-mo), German EPIC-Potsdam Validation Study (European Prospective Investigation into Cancer and Nutrition Potsdam Germany cohort) (n = 134, 12 24HR collected over 12-mo) and EPIC-Potsdam BMBF-II Study (Federal Ministry of Education and Research, "Bundesministerium für Bildung und Forschung") (n = 725, 4 24HR collected over 36 mo).

RESULTS

Measurement reliability of overnight fasting duration based on a single 24HR was "poor" in all studies [ICC range: 0.27; 95% CI: 0.23, 0.32 - 0.46; 95% CI: 0.43, 0.50]. Reliability was "moderate" with 3 24HR (ICC range: 0.53; 95% CI: 0.47, 0.58 in IDATA, 0.62; 95% CI: 0.52, 0.69 in the EPIC-Potsdam Validation Study, and 0.72; 95% CI: 0.70-0.75 in the EPIC-Potsdam BMBF-II Study). Results were similar for the midpoint of overnight fasting time and the number of eating episodes. Reliability of measuring late eating was "fair" in IDATA (Light's Kappa: 0.30; 95% CI: 0.21, 0.39) and "slight" in the EPIC-Potsdam Validation study and the EPIC-Potsdam BMBF-II study (Light's Kappa: 0.19; 95% CI: 0.15, 0.25 and 0.09; 95% CI: 0.06, 0.12, respectively). Reliability estimates differed by sex, BMI, weekday, and season of 24HR administration in some studies.

CONCLUSIONS

Our results show that ≥ 3 24HR over a 1-3-y period are required for reliable estimates of meal timing variables.

Plasma Industrial and Ruminant Trans Fatty Acids and Incident Type 2 Diabetes in the EPIC-Potsdam Cohort

OBJECTIVE

Although dietary intake of trans fatty acid (TFA) is a major public health concern because of the associated increase in the risk of cardiovascular events, it remains unclear whether TFAs also influence risk of type 2 diabetes (T2D) and whether industrial TFAs (iTFAs) and ruminant TFAs (rTFAs) exert the same effect on health.

RESEARCH DESIGN AND METHODS

To investigate the relationship of 7 rTFAs and iTFAs, including 2 conjugated linoleic acids (CLAs), plasma phospholipid TFAs were measured in a case-cohort study nested within the European Prospective Investigation Into Cancer and Nutrition-Potsdam cohort. The analytical sample was a random subsample (n = 1,248) and incident cases of T2D (n = 801) over a median follow-up of 6.5 years. Using multivariable Cox regression models, we examined associations of TFAs with incident T2D.

RESULTS

The TFA subtypes were intercorrelated with each other, with other fatty acids, and with different food sources. After controlling for other TFAs, the iTFAs (18:1n-6t, 18:1n-9t, 18:2n-6,9t) were not associated with diabetes risk. Some rTFA subtypes were inversely associated with diabetes risk: vaccenic acid (18:1n-7t; hazard ratio [HR] per SD 0.72; 95% CI 0.58-0.89) and t10c12-CLA (HR per SD 0.81; 95% CI 0.70-0.94), whereas c9t11-CLA was positively associated (HR per SD 1.39; 95% CI 1.19-1.62). Trans-palmitoleic acid (16:1n-7t) was not associated with diabetes risk when adjusting for the other TFAs (HR per SD 1.08; 95% CI 0.88-1.31).

CONCLUSIONS

The TFAs' conformation plays an essential role in their relationship to diabetes risk. rTFA subtypes may have opposing relationships to diabetes risk. Previous observations for reduced diabetes risk with higher levels of circulating trans-palmitoleic acid are likely due to confounding.

Dihydroceramide- and ceramide-profiling provides insights into human cardiometabolic disease etiology

Metabolic alterations precede cardiometabolic disease onset. Here we present ceramide- and dihydroceramide-profiling data from a nested case-cohort (type 2 diabetes [T2D, n = 775]; cardiovascular disease [CVD, n = 551]; random subcohort [n = 1137]) in the prospective EPIC-Potsdam study. We apply the novel NetCoupler-algorithm to link a data-driven (dihydro)ceramide network to T2D and CVD risk. Controlling for confounding by other (dihydro)ceramides, ceramides C18:0 and C22:0 and dihydroceramides C20:0 and C22:2 are associated with higher and ceramide C20:0 and dihydroceramide C26:1 with lower T2D risk. Ceramide C16:0 and dihydroceramide C22:2 are associated with higher CVD risk. Genome-wide association studies and Mendelian randomization analyses support a role of ceramide C22:0 in T2D etiology. Our results also suggest that (dh)ceramides partly mediate the putative adverse effect of high red meat consumption and benefits of coffee consumption on T2D risk. Thus, (dihydro)ceramides may play a critical role in linking genetic predisposition and dietary habits to cardiometabolic disease risk.

Among lipid classes, ceramides are linked to impaired cardiometabolic health. Here the authors report the association of specific ceramides and dihydroceramides on the risk of developing type 2 diabetes and or cardiovascular disease in a prospective population cohort.

Impact of Actual Use Behavior of Healthcare Wearable Devices on the Quality of Life: A Cross-Sectional Survey of People with Dementia and Their Caregivers in Ghana

The increasing prevalence of dementia has necessitated the introduction and use of healthcare wearable devices to augment the healthcare services delivered to people with dementia (PWDs). Unfortunately, evidence on user feedback and the real impact of the actual use of these devices on the quality of life of PWDs has not been fully explored, especially in the context of developing countries. This study, therefore, seeks to evaluate the impact of actual use behavior (AUB) of healthcare wearable devices on the quality of life (QoL) of PWDs in Ghana by using constructs from the extended Unified Theory of Acceptance and Use of Technology (UTAUT2) model and the SF-36 quality of life instrument. Data were collected from people with dementia and, in some cases, caregivers (acting as proxies) in three administrative regions of Ghana using structured questionnaires. Of the 420 questionnaires distributed, 356 were returned, giving a response rate of (356/420, 84.8%). Three hundred and twenty (320) responses were used for further analysis, employing the Partial Least Squares based on Structural Equation Modeling. The results showed a significant positive relationship between AUB and QoL (p < 0.001). Other predictors such as behavioral intention, facilitating conditions, effort expectancy and social influence were also found to significantly impact the actual use behavior of healthcare wearable devices among PWDs. The study also revealed that 4% (14) of patients rated their reported health transition associated with the use of healthcare wearable devices as excellent, 42.5% (136) as very good, and 39.4% (126) as good, respectively at the time of the study compared to a year ago. This study provided empirical evidence of the positive impact of the actual use of healthcare wearable devices on the quality of life of PWDs and further highlighted the factors that drive actual use behavior among PWDs in Ghana. Based on the findings of this study, stakeholders need to create the necessary conditions that will facilitate the adoption and use of healthcare wearable devices, as this will help improve the quality of life, reduce the burden of the disease on caregivers, and enable independent living of PWDs.

Assessing the association of rs7574865 STAT4 gene variant and type 1 diabetes mellitus among Egyptian patients

Background

Variants in the signal transducer and activator of transcription 4 (STAT4) gene have an important role in the incident of multiple autoimmune diseases including type 1 diabetes mellitus (T1D). It is a genetically related auto-immune disorder that resulted from T cell-mediated destruction of pancreatic cells that are in control for the production of insulin in the blood. The current study aimed to clarify the role of STAT4 (rs7574865) variant allelic and genotypic variations in the susceptibility to type 1 diabetes among Egyptians by using the real-time PCR.

Results

A total of 100 patients and 100 controls were genotyped for rs7574865, and the biochemical and anthropometric parameters were measured to show that type 1 diabetic patients had significantly higher levels of HbA1c and triglycerides compared to non-diabetic individuals (P < 0.05). And genetically, the T allele and GT genotype have a significant correlation with diabetes type 1.

Conclusion

It was confirmed by this study that the rs7574865 T allele and GT genotype have a significant correlation with diabetes type 1 incidence among Egyptian patients.

Association of the odd-chain fatty acid content in lipid groups with type 2 diabetes risk: A targeted analysis of lipidomics data in the EPIC-Potsdam cohort

BACKGROUND

Plasma odd-chain saturated fatty acids (OCFA) are inversely associated with type 2 diabetes (T2D) risk and may serve as biomarkers for dairy fat intake. Their distribution across different lipid classes and consequences for diabetes risk remain unknown.

AIM

To investigate the prospective associations of OCFA-containing lipid species with T2D risk and their dietary determinants.

METHODS

Within the European Prospective Investigation into Cancer and Nutrition-Potsdam study (n = 27,548), we applied a nested case-cohort design (subcohort: n = 1,248; T2D cases: n = 820; median follow-up 6.5 years). OCFA-containing lipids included triacylglycerols, free fatty acids (FFA), cholesteryl esters (CE), phosphatidylcholines, phosphatidylethanolamines, lysophosphatidylcholines, lysophosphatidylethanolamines, monoacylglycerols, and diacylglycerols. We estimated lipid class-specific associations between OCFA-containing lipids and T2D in sex-stratified Cox proportional-hazards models. We investigated correlations between lipids and dietary intakes derived from food-frequency questionnaires.

RESULTS

We observed heterogeneous integration of OCFA in different lipid classes: triacylglycerols, FFA, CE, and phosphatidylcholines contributed most to the total OCFA-plasma abundance. The relative concentration of OCFA was particularly high in monoacylglycerols, and the contribution of C15:0 versus C17:0 to the total OCFA-abundance differed across lipid classes. In women, several OCFA-containing phospholipids were inversely associated with T2D risk [phosphatidylcholine(C15:0), HR Q5 vs Q1: 0.56, 95% CI 0.32-0.97; phosphatidylcholine(C17:0), HR per SD: 0.59, 95% CI 0.48-0.71; lysophosphatidylcholine(C17:0), HR Q5 vs Q1: 0.42, 95% CI 0.23-0.76]. In men, we did not detect statistically significant inverse associations in phospholipids, and lysophosphatidylcholine(C15:0) was associated with higher T2D risk (HR Q5 vs. Q1: 1.96, 95% CI 1.06-3.63). Besides, CE(C17:0), monoacylglycerols(C15:0), and diacylglycerols(C15:0) were inversely associated with T2D risk; FFA(C17:0) was positively associated with T2D risk in women. Consumption of fat-rich dairy and fiber-rich foods were positively and red meat inversely correlated to OCFA-containing lipid plasma levels.

CONCLUSIONS

OCFA-containing lipids are linked to T2D risk in a lipid class and sex-specific manner, and they are correlated with several foods.

BMI and BMI change following incident type 2 diabetes and risk of microvascular and macrovascular complications: the EPIC-Potsdam study

AIMS/HYPOTHESIS

Studies suggest decreased mortality risk among people who are overweight or obese compared with individuals with normal weight in type 2 diabetes (obesity paradox). However, the relationship between body weight or weight change and microvascular vs macrovascular complications of type 2 diabetes remains unresolved. We investigated the association between BMI and BMI change with long-term risk of microvascular and macrovascular complications in type 2 diabetes in a prospective cohort study.

METHODS

We studied participants with incident type 2 diabetes from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort, who were free of cancer, cardiovascular disease and microvascular disease at diagnosis (n = 1083). Pre-diagnosis BMI and relative annual change between pre- and post-diagnosis BMI were evaluated in multivariable-adjusted Cox models.

RESULTS

There were 85 macrovascular (myocardial infarction and stroke) and 347 microvascular events (kidney disease, neuropathy and retinopathy) over a median follow-up of 10.8 years. Median pre-diagnosis BMI was 29.9 kg/m² (IQR 27.4-33.2), and the median relative annual BMI change was -0.4% (IQR -2.1 to 0.9). Higher pre-diagnosis BMI was positively associated with total microvascular complications (multivariable-adjusted HR per 5 kg/m² [95% CI]: 1.21 [1.07, 1.36], kidney disease 1.39 [1.21, 1.60] and neuropathy 1.12 [0.96, 1.31]) but not with macrovascular complications (HR 1.05 [95% CI 0.81, 1.36]). Analyses according to BMI categories corroborated these findings. Effect modification was not evident by sex, smoking status or age groups. In analyses according to BMI change categories, BMI loss of more than 1% indicated a decreased risk of total microvascular complications (HR 0.62 [95% CI 0.47, 0.80]), kidney disease (HR 0.57 [95% CI 0.40, 0.81]) and neuropathy (HR 0.73 [95% CI 0.52, 1.03]), compared with participants with a stable BMI; no clear association was observed for macrovascular complications (HR 1.04 [95% CI 0.62, 1.74]). The associations between BMI gain compared with stable BMI and diabetes-related vascular complications were less apparent. Associations were consistent across strata of sex, age, pre-diagnosis BMI or medication but appeared to be stronger among never-smokers compared with current or former smokers.

CONCLUSIONS/INTERPRETATION

Among people with incident type 2 diabetes, pre-diagnosis BMI was positively associated with microvascular complications, while a reduced risk was observed with weight loss when compared with stable weight. The relationships with macrovascular disease were less clear.

Trace element profile and incidence of type 2 diabetes, cardiovascular disease and colorectal cancer: results from the EPIC-Potsdam cohort study

PURPOSE

We aimed to examine the prospective association between manganese, iron, copper, zinc, iodine, selenium, selenoprotein P, free zinc, and their interplay, with incident type 2 diabetes (T2D), cardiovascular disease (CVD) and colorectal cancer (CRC).

METHODS

Serum trace element (TE) concentrations were measured in a case-cohort study embedded within the EPIC-Potsdam cohort, consisting of a random sub-cohort (n = 2500) and incident cases of T2D (n = 705), CVD (n = 414), and CRC (n = 219). TE patterns were investigated using principal component analysis. Cox proportional hazard models were fitted to examine the association between TEs with T2D, CVD and CRC incidence.

RESULTS

Higher manganese, zinc, iodine and selenium were associated with an increased risk of developing T2D (HR Q5 vs Q1: 1.56, 1.09-2.22; HR per SD, 95% CI 1.18, 1.05-1.33; 1.09, 1.01-1.17; 1.19, 1.06-1.34, respectively). Regarding CVD, manganese, copper and copper-to-zinc ratio were associated with an increased risk (HR per SD, 95% CI 1.13, 1.00-1.29; 1.22, 1.02-1.44; 1.18, 1.02-1.37, respectively). The opposite was observed for higher selenium-to-copper ratio (HR Q5 vs Q1, 95% CI 0.60, 0.39-0.93). Higher copper and zinc were associated with increasing risk of developing CRC (HR per SD, 95% CI 1.29, 1.05-1.59 and 1.14, 1.00-1.30, respectively). Selenium, selenoprotein P and selenium-to-copper-ratio were associated to decreased risk (HR per SD, 95% CI 0.82, 0.69-0.98; 0.81, 0.72-0.93; 0.77, 0.65-0.92, respectively). Two TE patterns were identified: manganese-iron-zinc and copper-iodine-selenium.

CONCLUSION

Different TEs were associated with the risk of developing T2D, CVD and CRC. The contrasting associations found for selenium with T2D and CRC point towards differential disease-related pathways.

The reliability and relative validity of predefined dietary patterns were higher than that of exploratory dietary patterns in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam population

The aim of this study was to assess the ability of the FFQ to describe reliable and valid dietary pattern (DP) scores. In a total of 134 participants of the European Prospective Investigation into Cancer and Nutrition-Potsdam study aged 35–67 years, the FFQ was applied twice (baseline and after 1 year) to assess its reliability. Between November 1995 and March 1997, twelve 24-h dietary recalls (24HDR) as reference instrument were applied to assess the validity of the FFQ. Exploratory DP were derived by principal component analyses. Investigated predefined DP were the Alternative Healthy Eating Index (AHEI) and two Mediterranean diet indices. From dietary data of each FFQ, two exploratory DP were retained, but differed in highly loading food groups, resulting in moderate correlations (r 0·45–0·58). The predefined indices showed higher correlations between the FFQ (r(AHEI) 0·62, r(Mediterranean Diet Pyramid Index (MedPyr)) 0·62 and r(traditional Mediterranean Diet Score (tMDS)) 0·51). From 24HDR dietary data, one exploratory DP retained differed in composition to the first FFQ-based DP, but showed similarities to the second DP, reflected by a good correlation (r 0·70). The predefined DP correlated moderately (r 0·40–0·60). To conclude, long-term analyses on exploratory DP should be interpreted with caution, due to only moderate reliability. The validity differed extensively for the two exploratory DP. The investigated predefined DP showed a better reliability and a moderate validity, comparable to other studies. Within the two Mediterranean diet indices, the MedPyr performed better than the tMDs in this middle-aged, semi-urban German study population.

Associations of short stature and components of height with incidence of type 2 diabetes: mediating effects of cardiometabolic risk factors

AIMS/HYPOTHESIS

This study aimed to evaluate associations of height as well as components of height (sitting height and leg length) with risk of type 2 diabetes and to explore to what extent associations are explainable by liver fat and cardiometabolic risk markers.

METHODS

A case-cohort study within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study comprising 26,437 participants who provided blood samples was designed. We randomly selected a subcohort of 2500 individuals (2029 diabetes-free at baseline and with anamnestic, anthropometrical and metabolic data for analysis). Of the 820 incident diabetes cases identified in the full cohort during 7 years of follow-up, 698 remained for analyses after similar exclusions.

RESULTS

After adjustment for age, potential lifestyle confounders, education and waist circumference, greater height was related to lower diabetes risk (HR per 10 cm, men 0.59 [95% CI 0.47, 0.75] and women 0.67 [0.51, 0.88], respectively). Leg length was related to lower risk among men and women, but only among men if adjusted for total height. Adjustment for liver fat and triacylglycerols, adiponectin and C-reactive protein substantially attenuated associations between height and diabetes risk, particularly among women.

CONCLUSIONS/INTERPRETATION

We observed inverse associations between height and risk of type 2 diabetes, which was largely related to leg length among men. The inverse associations may be partly driven by lower liver fat content and a more favourable cardiometabolic profile.

The accumulation of deficits approach to describe frailty

The advancing age of the participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study was the incentive to investigate frailty as a major parameter of ageing. The aim of this study was to develop a multidimensional tool to measure frailty in an ageing, free-living study population. The "accumulation of deficits approach" was used to develop a frailty index (FI) to characterize a sub-sample (N = 815) of the EPIC-Potsdam (EPIC-P) study population regarding the aging phenomenon. The EPIC-P frailty index (EPIC-P-FI) included 32 variables from the following domains: health, physical ability, psychosocial and physiological aspects. P-values were calculated for the linear trend between sociodemographic and life style variables and the EPIC-P-FI was calculated using regression analysis adjusted for age. The relationship between the EPIC-P-FI and age was investigated using fractional polynomials. Some characteristics such as age, education, time spent watching TV, cycling and a biomarker of inflammation (C-reactive protein) were associated with frailty in men and women. Interestingly, living alone, having no partner and smoking status were only associated with frailty in men, and alcohol use and physical fitness (VO2max) only in women. The generated, multidimensional FI, adapted to the EPIC-P study, showed that this cohort is a valuable source for further exploration of factors that promote healthy ageing.

Traditional risk factors for essential hypertension: analysis of their specific combinations in the EPIC-Potsdam cohort

Appropriate interventions might improve the prevention of essential hypertension. This requires a comprehensive view of modifiable lifestyle factors (MLFs) distribution and effect. To determine how six MLFs (general adiposity, abdominal adiposity, alcohol consumption, smoking, diet, physical inactivity) for risk of hypertension are distributed and how their combinations affect the risk, a prospective study cohort of 11,923 healthy participants from the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study was used. Of these, 1,635 developed hypertension during a mean follow-up of 10.3 years. Mutually exclusive combinations, clustering and interactions of MLFs were then investigated stratifying by sex, Hazard Ratios (HRs) and Population Attributable Risks (PARs%) were calculated. General adiposity alone was sufficient to increase the risk of hypertension (HR = 1.86, PAR% 3.36), and in this cohort it played a major role in enhancing the risk of hypertension, together with smoking and physical inactivity. MLFs had a different impact and a different modulation of risk in women and men, and they showed a remarkable tendency to occur in specific patterns with higher prevalence than expected. This indication can help to promote a holistic approach through multifactorial preventive strategies addressing more than a factor at a time. For prevention of hypertension addressing adiposity together with smoking, promoting at the same time physical activity should be the first choice.

Genetic variants including markers from the exome chip and metabolite traits of type 2 diabetes

Diabetes-associated metabolites may aid the identification of new risk variants for type 2 diabetes. Using targeted metabolomics within a subsample of the German EPIC-Potsdam study (n = 2500), we tested previously published SNPs for their association with diabetes-associated metabolites and conducted an additional exploratory analysis using data from the exome chip including replication within 2,692 individuals from the German KORA F4 study. We identified a total of 16 loci associated with diabetes-related metabolite traits, including one novel association between rs499974 (MOGAT2) and a diacyl-phosphatidylcholine ratio (PC aa C40:5/PC aa C38:5). Gene-based tests on all exome chip variants revealed associations between GFRAL and PC aa C42:1/PC aa C42:0, BIN1 and SM (OH) C22:2/SM C18:0 and TFRC and SM (OH) C22:2/SM C16:1). Selecting variants for gene-based tests based on functional annotation identified one additional association between OR51Q1 and hexoses. Among single genetic variants consistently associated with diabetes-related metabolites, two (rs174550 (FADS1), rs3204953 (REV3L)) were significantly associated with type 2 diabetes in large-scale meta-analysis for type 2 diabetes. In conclusion, we identified a novel metabolite locus in single variant analyses and four genes within gene-based tests and confirmed two previously known mGWAS loci which might be relevant for the risk of type 2 diabetes.

Associations of anthropometric markers with serum metabolites using a targeted metabolomics approach: results of the EPIC-potsdam study

Background/Objectives:

The metabolic consequences of type of body shape need further exploration. Whereas accumulation of body mass in the abdominal area is a well-established metabolic risk factor, accumulation in the gluteofemoral area is controversially debated. We evaluated the associations of anthropometric markers of overall body mass and body shape with 127 serum metabolites within a sub-sample of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort.

Subjects/Methods:

The cross-sectional analysis was conducted in 2270 participants, randomly drawn from the EPIC-Potsdam cohort. Metabolites were measured by targeted metabolomics. To select metabolites related with both waist circumference (WC) (abdominal subcutaneous and visceral fat) and hip circumference (HC) (gluteofemoral fat, muscles and bone structure) correlations (r) with body mass index (BMI) as aggregating marker of body mass (lean and fat mass) were calculated. Relations with body shape were assessed by median metabolite concentrations across tertiles of WC and HC, mutually adjusted to each other.

Results:

Correlations revealed 23 metabolites related to BMI (r⩾I0.20 I). Metabolites showing relations with BMI were showing similar relations with HC adjusted WC (WC_HC). In contrast, relations with WC adjusted HC (HC_WC) were less concordant with relations of BMI and WC_HC. In both sexes, metabolites with concordant relations regarding WC_HC and HC_WC included tyrosine, diacyl-phosphatidylcholine C38:3, C38:4, lyso-phosphatidylcholine C18:1, C18:2 and sphingomyelin C18:1; metabolites with opposite relations included isoleucine, diacyl-phosphatidylcholine C42:0, acyl–alkyl-phosphatidylcholine C34:3, C42:4, C42:5, C44:4 and C44:6. Metabolites specifically related to HC_WC included acyl–alkyl-phosphatidylcholine C34:2, C36:2, C38:2 and C40:4, and were solely observed in men. Other metabolites were related to WC_HC only.

Conclusions:

The study revealed specific metabolic profiles for HC_WC as marker of gluteofemoral body mass differing from those for BMI and WC_HC as markers of overall body mass and abdominal fat, respectively. Thus, the study suggests that gluteofemoral mass may have less-adverse metabolic implications than abdominal fat.

Insulin-Like Growth Factor 1 and Insulin-Like Growth Factor-Binding Protein 3 in Relation to the Risk of Type 2 Diabetes Mellitus: Results From the EPIC-Potsdam Study

Higher levels of insulin-like growth factor-binding protein 3 (IGFBP-3) might raise the risk of type 2 diabetes mellitus (T2DM) via binding of insulin-like growth factor 1 (IGF-1), an insulin-like hormone that is involved in glucose homeostasis. We investigated serum concentrations of IGF-1 and IGFBP-3 and their molar ratio in relation to T2DM incidence in a nested case-cohort study within the European Prospective Investigation Into Cancer and Nutrition-Potsdam Study. We included a randomly selected subcohort of persons without T2DM at the time of blood sampling (n = 2,269) and 776 individuals with incident T2DM identified between 1994 and 2005. For the highest quartile versus lowest, the multivariable-adjusted hazard rate ratios were 0.91 (95% confidence interval (CI): 0.68, 1.23; P for trend = 0.31) for IGF-1, 1.33 (95% CI: 1.00, 1.76; P for trend = 0.04) for IGFBP-3, and 0.77 (95% CI: 0.57, 1.03; P for trend = 0.03) for IGF-1:IGFBP-3 ratio. IGFBP-3 level remained positively associated with T2DM incidence-and the ratio of IGF-1 to IGFBP-3 was inversely related with T2DM incidence--in models that included adjustment for IGF-1 concentrations (P for trend < 0.05). Therefore, our findings do not confirm an association between total IGF-1 concentrations and risk of T2DM in the general study population, although higher IGFBP-3 levels might raise T2DM risk independent of IGF-1 levels.

Association between the Fatty Liver Index and Risk of Type 2 Diabetes in the EPIC-Potsdam Study

The fatty liver index (FLI) predicts fatty liver by using BMI, waist circumference, γ-glutamyltransferase and triglycerides. We investigated the association between the FLI and the risk of type 2 diabetes and evaluated to what extent single FLI components contribute to the diabetes risk. We analysed a case-cohort study (random sub-cohort: 1922; incident cases: 563) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study. The proportion of exposure effect (PEE) explained by single FLI components was evaluated and effect decomposition using inverse probability weighting (IPW) was applied. Women and men with a FLI ≥60 compared to those with a FLI <30 had a multivariable-adjusted Hazard Ratio (HR) of 17.6; 95% confidence interval (CI) 11.1-28.0 and HR: 10.9; 95% CI 6.22-19.2, respectively. Adjustment for BMI or waist circumference attenuated this association in men [PEE_BMI (95% CI) = 53.8% (43.9%-65.8%); PEE_waist (95% CI) = 54.8% (44.2%-68.8%)]. In women, adjustment for waist circumference attenuated the association to a lesser degree than in men [PEE_waist (95% CI) = 31.1%; (21.9%-43.1%)] while BMI had no appreciable effect [PEE_BMI (95% CI) = 11.0% (2.68%-21.0%)]. γ-glutamyltransferase and triglycerides showed only a small attenuation in women [PEE_GGT(95% CI) = 3.11% (-0.72%-4.48%); PEE_TG (95% CI) = 6.36% (3.81%-9.92%)] and in men [PEE_GGT = 0%; PEE_TG (95% CI) = 6.23% (2.03%-11.8%)]. In women, the total effect was decomposed into a direct effect and 4 indirect effects (HR_BMI = 1.10; HR_waist = 1.28; HR_GGT = 0.97 and HR_TG = 1.03). In men, the 4 indirect effects were HR_BMI = 1.25; HR_waist = 1.29; HR_GGT = 0.97 and HR_TG = 0.99. These data suggest that the FLI, as a proxy for fatty liver, is associated with risk of type 2 diabetes. This association is only partly explained by standard estimates of overall and abdominal body fatness, particularly among women.

Untargeted metabolic profiling identifies altered serum metabolites of type 2 diabetes mellitus in a prospective, nested case control study

BACKGROUND

Application of metabolite profiling could expand the etiological knowledge of type 2 diabetes mellitus (T2D). However, few prospective studies apply broad untargeted metabolite profiling to reveal the comprehensive metabolic alterations preceding the onset of T2D.

METHODS

We applied untargeted metabolite profiling in serum samples obtained from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort comprising 300 individuals who developed T2D after a median follow-up time of 6 years and 300 matched controls. For that purpose, we used ultraperformance LC-MS with a protocol specifically designed for large-scale metabolomics studies with regard to robustness and repeatability. After multivariate classification to select metabolites with the strongest contribution to disease classification, we applied multivariable-adjusted conditional logistic regression to assess the association of these metabolites with T2D.

RESULTS

Among several alterations in lipid metabolism, there was an inverse association with T2D for metabolites chemically annotated as lysophosphatidylcholine(dm16:0) and phosphatidylcholine(O-20:0/O-20:0). Hexose sugars were positively associated with T2D, whereas higher concentrations of a sugar alcohol and a deoxyhexose sugar reduced the odds of diabetes by approximately 60% and 70%, respectively. Furthermore, there was suggestive evidence for a positive association of the circulating purine nucleotide isopentenyladenosine-5'-monophosphate with incident T2D.

CONCLUSIONS

This study constitutes one of the largest metabolite profiling approaches of T2D biomarkers in a prospective study population. The findings might help generate new hypotheses about diabetes etiology and develop further targeted studies of a smaller number of potentially important metabolites.

Evaluation of 41 candidate gene variants for obesity in the EPIC-Potsdam cohort by multi-locus stepwise regression

OBJECTIVE

Obesity has become a leading preventable cause of morbidity and mortality in many parts of the world. It is thought to originate from multiple genetic and environmental determinants. The aim of the current study was to introduce haplotype-based multi-locus stepwise regression (MSR) as a method to investigate combinations of unlinked single nucleotide polymorphisms (SNPs) for obesity phenotypes.

METHODS

In 2,122 healthy randomly selected men and women of the EPIC-Potsdam cohort, the association between 41 SNPs from 18 obesity-candidate genes and either body mass index (BMI, mean=25.9 kg/m(2), SD=4.1) or waist circumference (WC, mean=85.2 cm, SD=12.6) was assessed. Single SNP analyses were done by using linear regression adjusted for age, sex, and other covariates. Subsequently, MSR was applied to search for the 'best' SNP combinations. Combinations were selected according to specific AICc and p-value criteria. Model uncertainty was accounted for by a permutation test.

RESULTS

The strongest single SNP effects on BMI were found for TBC1D1 rs637797 (β = -0.33, SE=0.13), FTO rs9939609 (β=0.28, SE=0.13), MC4R rs17700144 (β=0.41, SE=0.15), and MC4R rs10871777 (β=0.34, SE=0.14). All these SNPs showed similar effects on waist circumference. The two 'best' six-SNP combinations for BMI (global p-value= 3.45⋅10(-6) and 6.82⋅10(-6)) showed effects ranging from -1.70 (SE=0.34) to 0.74 kg/m(2) (SE=0.21) per allele combination. We selected two six-SNP combinations on waist circumference (global p-value = 7.80⋅10(-6) and 9.76⋅10(-6)) with an allele combination effect of -2.96 cm (SE=0.76) at maximum. Additional adjustment for BMI revealed 15 three-SNP combinations (global p-values ranged from 3.09⋅10(-4) to 1.02⋅10(-2)). However, after carrying out the permutation test all SNP combinations lost significance indicating that the statistical associations might have occurred by chance.

CONCLUSION

MSR provides a tool to search for risk-related SNP combinations of common traits or diseases. However, the search process does not always find meaningful SNP combinations in a dataset.

Identification of serum metabolites associated with risk of type 2 diabetes using a targeted metabolomic approach

Metabolomic discovery of biomarkers of type 2 diabetes (T2D) risk may reveal etiological pathways and help to identify individuals at risk for disease. We prospectively investigated the association between serum metabolites measured by targeted metabolomics and risk of T2D in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam (27,548 adults) among all incident cases of T2D (n = 800, mean follow-up 7 years) and a randomly drawn subcohort (n = 2,282). Flow injection analysis tandem mass spectrometry was used to quantify 163 metabolites, including acylcarnitines, amino acids, hexose, and phospholipids, in baseline serum samples. Serum hexose; phenylalanine; and diacyl-phosphatidylcholines C32:1, C36:1, C38:3, and C40:5 were independently associated with increased risk of T2D and serum glycine; sphingomyelin C16:1; acyl-alkyl-phosphatidylcholines C34:3, C40:6, C42:5, C44:4, and C44:5; and lysophosphatidylcholine C18:2 with decreased risk. Variance of the metabolites was largely explained by two metabolite factors with opposing risk associations (factor 1 relative risk in extreme quintiles 0.31 [95% CI 0.21-0.44], factor 2 3.82 [2.64-5.52]). The metabolites significantly improved T2D prediction compared with established risk factors. They were further linked to insulin sensitivity and secretion in the Tübingen Family study and were partly replicated in the independent KORA (Cooperative Health Research in the Region of Augsburg) cohort. The data indicate that metabolic alterations, including sugar metabolites, amino acids, and choline-containing phospholipids, are associated early on with a higher risk of T2D.

Heterogeneity of the Stearoyl-CoA desaturase-1 (SCD1) gene and metabolic risk factors in the EPIC-Potsdam study

BACKGROUND

Stearoyl-CoA desaturase-1 (SCD1) is an enzyme involved in lipid metabolism. In mice and humans its activity has been associated with traits of the metabolic syndrome, but also with the prevention of saturated fatty acids accumulation and subsequent inflammation, whereas for liver fat content inconsistent results have been reported. Thus, variants of the gene encoding SCD1 (SCD1) could potentially modify metabolic risk factors, but few human studies have addressed this question.

METHODS

In a sample of 2157 middle-aged men and women randomly drawn from the Potsdam cohort of the European Prospective Investigation into Cancer and Nutrition, we investigated the impact of 7 SCD1 tagging-single nucleotide polymorphisms (rs1502593, rs522951, rs11190480, rs3071, rs3793767, rs10883463 and rs508384) and 5 inferred haplotypes with frequency >5% describing 90.9% of the genotype combinations in our population, on triglycerides, body mass index (BMI), waist circumference (WC), glycated haemoglobin (HbA1c), high-sensitivity C-reactive protein (hs-CRP), gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT) and fetuin-A.

RESULTS

No significant associations between any of the SNPs or haplotypes and BMI, WC, fetuin-A and hs-CRP were observed. Associations of rs10883463 with triglycerides, GGT and HbA1c as well as of rs11190480 with ALT activity, were weak and became non-significant after multiple-testing correction. Also associations of the haplotype harbouring the minor allele of rs1502593 with HbA1c levels, the haplotype harbouring the minor alleles of rs11190480 and rs508384 with activity of ALT, and the haplotype harbouring the minor alleles of rs522951, rs10883463 and rs508384 with triglyceride and HbA1C levels and GGT activities did not withstand multiple-testing correction.

CONCLUSION

These findings suggest that there are no associations between common variants of SCD1 or its inferred haplotypes and the investigated metabolic risk factors. However, given the results from animal models, heterogeneity of human SCD1 warrants further investigation, in particular with regard to rare variants.

Effects of selenium status, dietary glucosinolate intake and serum glutathione S-transferase α activity on the risk of benign prostatic hyperplasia

Study Type--Prognosis (case control) Level of Evidence 2. What's known on the subject? and What does the study add? Geographical and ethnic differences in the distribution of BPH and the results of migrant studies indicate that not only age, androgens and genetics, but also modifiable factors may play a role in the aetiology of BPH. Oxidative stress induced by chronic inflammation could be a cause and antioxidants, including selenoproteins, may reduce the risk. The published data related to this topic are scarce and are mainly based on cross-sectional and case-control studies. In a nested case-control study, we observed a significant inverse association between serum selenium concentrations and the risk of BPH. These results need to be confirmed in larger, prospective epidemiological studies. Prostate enlargement is an increasing health problem as a result of an ageing population in many countries. Modifiable factors may also play a role. In the present study, before this antioxidant can be recommended as a preventive measure.

OBJECTIVE

• To determine whether geographical differences in the distribution of benign prostatic hyperplasia (BPH) and migrant studies indicate that modifiable factors play a role in the aetiology of BPH. Oxidative stress produced by chronic inflammation could represent one of the causes, and antioxidants, including selenoproteins, may reduce the risk.

SUBJECTS AND METHODS

• Conditional logistic regression was used to examine the associations of serum selenium and selenoprotein P concentrations and glutathione peroxidase activity with respect to the risk of BPH in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition-Heidelberg cohort, including 111 cases and 214 matched controls. • In addition, dietary glucosinolate intake and the serum glutathione S-transferase α concentration was investigated.

RESULTS

• The risk of BPH significantly decreased with an increasing serum selenium concentration; the risk estimate was 0.83 (35% CI 0.69-0.99) per 10 µg/L increase in serum selenium concentration. • However, no significant association was present for serum selenoprotein P concentration or glutathione peroxidase activity. Risk estimates for BPH decreased with a higher intake of glucosinolates, although the results were not statistically significant.

CONCLUSION

• A low serum selenium concentration may increase the risk of BPH, although the findings reported in the present study need to be confirmed in larger, well-designed epidemiological studies.

Body adiposity index, body fat content and incidence of type 2 diabetes

AIMS/HYPOTHESIS

The aim of this study was to compare estimates of body fat content, i.e. body adiposity index (BAI), BMI and waist and hip circumferences, with respect to their ability to predict the percentage of body fat (PBF; confirmed by magnetic resonance tomography) and incident type 2 diabetes.

METHODS

Associations between anthropometric measurements and PBF were evaluated in the Tübingen Lifestyle Intervention Program (TULIP; 138 men, 222 women), and between these measurements and incident type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study (9,729 men, 15,438 women) and the Cooperative Health Research in the Region of Augsburg (KORA) study (5,573 men, 5,628 women), using correlation and multivariate Cox regression analyses.

RESULTS

BMI more strongly correlated with PBF (men: r = 0.81, women: r = 0.84) than BAI (r = 0.68 and 0.81, respectively), while waist circumference among men (r = 0.84) and hip circumference among women (r = 0.88) showed the strongest correlations. BAI overestimated PBF among men (mean difference -3.0%), and this error was dependent on the value of PBF. BAI was more weakly associated with diabetes risk (RRs for 1 SD, EPIC-Potsdam men: 1.62 [95% CI 1.52, 1.72], women: 1.67 [95% CI 1.55, 1.80]; KORA men: 1.62 [95% CI 1.48, 1.78], women: 1.82 [95% CI 1.65, 2.02]) compared with BMI (RRs, EPIC-Potsdam men: 1.95 [95% CI 1.83, 2.09], women 1.88 [95% CI 1.76, 2.02], KORA men 1.75 [95% CI 1.62, 1.89], women 2.00 [95% CI 1.81, 2.22]), while waist circumference showed the strongest associations (RRs: 2.17 [95% CI 2.01, 2.35], 2.33 [95% CI 2.15, 2.53], 1.81 [95% CI 1.66, 1.96] and 2.29 [95% CI 2.05, 2.57] for EPIC-Potsdam men and women and KORA men and women, respectively).

CONCLUSIONS/INTERPRETATION

Waist circumference in men and hip circumference in women are better predictors of PBF than BAI and BMI. BAI was not as strong a predictor of diabetes as BMI, while waist circumference was the strongest predictor.

Alcohol consumption, genetic variants in alcohol deydrogenases, and risk of cardiovascular diseases: a prospective study and meta-analysis

Objective

First, to investigate and compare associations between alcohol consumption and variants in alcohol dehydrogenase (ADH) genes with incidence of cardiovascular diseases (CVD) in a large German cohort. Second, to quantitatively summarize available evidence of prospective studies on polymorphisms in ADH1B and ADH1C and CVD-risk.

Methods

We conducted a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort including a randomly drawn subcohort (n = 2175) and incident cases of myocardial infarction (MI; n = 230) or stroke (n = 208). Mean follow-up time was 8.2±2.2 years. The association between alcohol consumption, ADH1B or ADH1C genotypes, and CVD-risk was assessed using Cox proportional hazards regression. Additionally, we report results on associations of variants in ADH1B and ADH1C with ischemic heart disease and stroke in the context of a meta-analysis of previously published prospective studies published up to November 2011.

Results

Compared to individuals who drank >0 to 6 g alcohol/d, we observed a reduced risk of MI among females consuming >12 g alcohol/d (HR = 0.31; 95% CI: 0.10–0.97) and among males consuming >24 to 60 g/d (HR = 0.57; 95% CI: 0.33–0.98) or >60 g alcohol/d (HR = 0.30; 95% CI: 0.12–0.78). Stroke risk was not significantly related to alcohol consumption >6 g/d, but we observed an increased risk of stroke in men reporting no alcohol consumption. Individuals with the slow-coding ADH1B*1/1 genotype reported higher median alcohol consumption. Yet, polymorphisms in ADH1B or ADH1C were not significantly associated with risk of CVD in our data and after pooling results of eligible prospective studies [ADH1B*1/1: RR = 1.35 (95% CI: 0.98–1.88; p for heterogeneity: 0.364); ADH1C*2/2: RR = 1.07 (95% CI: 0.90–1.27; p for heterogeneity: 0.098)].

Conclusion

The well described association between alcohol consumption and CVD-risk is not reflected by ADH polymorphisms, which modify the rate of ethanol oxidation.

Erythrocyte membrane phospholipid fatty acids, desaturase activity, and dietary fatty acids in relation to risk of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study

BACKGROUND

The long-term role of fatty acids (FAs) in the cause of diabetes remains largely unclear.

OBJECTIVE

We aimed to investigate erythrocyte membrane FAs, desaturase activity, and dietary FAs in relation to the incidence of type 2 diabetes.

DESIGN

We applied a nested case-cohort design (n = 2724, including 673 incident diabetes cases) within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study, which involves 27,548 middle-aged subjects. Thirty erythrocyte membrane FAs (percentage of total FAs) and FA intake (percentage of total fat) were measured at baseline, and physician-confirmed incident diabetes was assessed during a mean follow-up of 7.0 y. We evaluated Δ⁵ desaturase (D5D) and Δ⁶ desaturase (D6D) activity by using FA product-to-precursor ratios (traditional approach) and by investigating variants in FADS1 and FADS2 genes that encode these desaturases (Mendelian randomization approach).

RESULTS

As a main finding, erythrocyte 16:1n-7 and 18:3n-6 and FA ratios, which reflect stearoyl coenzyme A desaturase (SCD) and D6D activity, were directly related to diabetes risk in multivariable-adjusted models [relative risks (95% CIs) comparing extreme quintiles: 16:1n-7, 2.11 (1.46, 3.05); 18:3n-6, 2.00 (1.38, 2.88); SCD, 2.61 (1.75, 3.89); and D6D, 2.46 (1.67, 3.63)], whereas the FA ratio that reflects D5D activity was inversely associated with risk [0.46 (0.31, 0.70)]. The Mendelian randomization approach corroborated the direct relation for D6D activity and tended to support the inverse relation for D5D activity. Proportions of dietary FAs showed only modest to low correlations with erythrocyte FAs and were not significantly associated with risk.

CONCLUSION

The FA profile of erythrocyte membrane phospholipids and activity of desaturase enzymes are strongly linked to the incidence of type 2 diabetes.

Plasma γ-Glutamyltransferase, Cysteinyl-Glycine, and Oxidized Low-Density Lipoprotein

Objective— To investigate the interrelation between plasma γ-glutamyltransferase (GGT) activity, cysteinyl-glycine (Cys-Gly) (ie, a thiol originating from GGT-mediated cleavage of glutathione), and oxidized low-density lipoprotein (oxLDL) with regard to myocardial infarction (MI) risk in a prospective study.

Methods and Results— Incident cases of MI were identified among European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam participants without prior MI during 6.0 years of follow-up. Baseline levels of Cys-Gly and oxLDL and GGT activity in plasma were measured in a case-cohort study comprising 837 subjects without incident MI and 116 subjects with incident MI. The relation of GGT, Cys-Gly and oxLDL to MI risk was assessed using Cox proportional hazards regression analysis. After adjustment for established risk factors, hazard ratios associated with a 1-SD unit increase in the log-transformed biomarker were 1.63 (95% CI, 1.30 to 2.05) for GGT, 1.36 (95% CI, 1.07 to 1.72) for Cys-Gly, and 1.37 (95% CI, 1.00 to 1.86) for oxLDL. Cys-Gly and oxLDL accounted for 2.3% of the relation between GGT and MI risk.

Conclusion— The positive association between GGT activity and MI risk appears to be independent of circulating Cys-Gly and oxLDL levels. With Cys-Gly, we found a potential new predictor of MI risk whose impact needs to be further elucidated.

Presence of gallstones or kidney stones and risk of type 2 diabetes

Recent evidence suggests that gallstones and kidney stones are associated with insulin resistance, but the relation between stone diseases and the risk of developing type 2 diabetes mellitus is not clear. Participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study (Potsdam, Germany) provided information about the presence of gallstones and kidney stones at recruitment between 1994 and 1998. On biennial questionnaires, participants reported newly diagnosed type 2 diabetes mellitus, and confirmation was obtained from treating physicians. During a mean follow-up period of 7.0 years between 1994 and 2005, 849 incident cases of type 2 diabetes were identified among 25,166 participants. After adjustment for sex, age, waist circumference, and lifestyle risk factors, persons with reported gallstones (n = 3,293) had an increased risk of type 2 diabetes (relative risk = 1.42, 95% confidence interval: 1.21, 1.68). Among the 23,817 participants with information on reported kidney stones (784 cases of incident diabetes), those who developed kidney stones (n = 2,468) were not at increased risk of diabetes in multivariable-adjusted models (relative risk = 1.05, 95% confidence interval: 0.86, 1.27). These findings suggest that gallstones, but not kidney stones, may predict the risk of developing type 2 diabetes, providing physicians with an interventional opportunity to implement adequate prevention measures.

Dietary glucosinolate intake and risk of prostate cancer in the EPIC-Heidelberg cohort study

Glucosinolates (GLS) are secondary plant metabolites occurring in cruciferous vegetables. Their biologically active break-down products show cancer preventive properties in animal and cell studies. So far, epidemiologic studies, using consumption of cruciferous vegetables as proxy for GLS intake, yielded inconsistent results. Here, we evaluated the association between dietary intake of GLS in comparison with consumption data of GLS-containing foods and the risk of prostate cancer. The study population comprised 11,405 male participants of the prospective EPIC-Heidelberg cohort study. During a mean follow-up time of 9.4 years, 328 incident cases of prostate cancer occurred. At recruitment, habitual food consumption was assessed by a validated food frequency questionnaire, and intake of individual GLS was estimated by means of a newly compiled database on food content of GLS. Adjusted hazard ratios (HR) for prostate cancer were calculated using the Cox proportional hazard model. Median daily intake of total GLS was 7.9 mg/day (interquartile range 5.1-11.9 mg/day). The risk of prostate cancer decreased significantly over quartiles of total GLS intake (multivariate HR [4th vs. 1st quartile] 0.68, 95% CI 0.48-0.97, p(trend) 0.03). Associations with GLS-containing food intake were weaker. Among GLS subgroups, aliphatic GLS showed the strongest inverse association with cancer risk. Analyses stratified by tumor stage and grade gave hint to inverse associations for localized and low-grade cancers. This study shows an inverse association between dietary intake of GLS and the risk of prostate cancer. Because this is the first prospective study using individual GLS intake data, confirmation in other studies is warranted.

Association of AHSG gene polymorphisms with fetuin-A plasma levels and cardiovascular diseases in the EPIC-Potsdam study

BACKGROUND

Elevated circulating levels of fetuin-A in blood have been associated with increased risk of cardiovascular disease. The goal of our study was to prospectively investigate the potential causal nature of the association between fetuin-A levels and myocardial infarction (MI) and ischemic stroke by applying a Mendelian randomization approach.

METHODS AND RESULTS

Five tagging single-nucleotide polymorphisms (rs2248690, rs2070633, rs2070635, rs4917, and rs6787344) capturing the common genetic variation of the fetuin-A coding gene alpha(2)-Heremans-Schmid glycoprotein (AHSG) were genotyped in a case-cohort comprising 214 MI cases, 154 ischemic stroke cases, and 2152 persons who remained free of cardiovascular disease events in the European Prospective Investigation into Cancer and Nutrition-Potsdam study. One single-nucleotide polymorphism (rs6787344) was discarded because of Hardy-Weinberg disequilibrium. All AHSG tagging single-nucleotide polymorphisms were associated with fetuin-A plasma levels (P<0.0001). AHSG rs4917 C>T showed the strongest association, explaining 21.2% of the phenotypic variance independent of potential confounding factors (+35.5 microg/mL increase per C-allele, P= 2 x 10(-121)). Furthermore, the rs4917 C-allele showed a significant association with MI (adjusted hazard rate ratio [RR] 1.34, 95% CI 1.05 to 1.70, P=0.02). Based on this association, the expected RR for MI corresponding to 1 SD in fetuin-A was 1.54 and, thus, strikingly matches the previously observed association between fetuin-A plasma levels and MI risk (RR 1.59).

CONCLUSIONS

These data provide evidence for the causal nature of the recently reported association between fetuin-A plasma levels and MI risk, thereby suggesting an involvement of fetuin-A in the pathogenesis of cardiovascular disease.

Association of the FTO rs9939609 single nucleotide polymorphism with C-reactive protein levels

Adipose tissue is a key factor determining C-reactive protein (CRP) plasma levels. Variation at the fat-mass and obesity-associated (FTO) gene locus has been reported to be associated with increased body fat. We investigated whether the FTO rs9939609 T>A single nucleotide polymorphism might alter CRP levels in a population-based sample of 2,415 participants from a large prospective cohort study. Genotype/phenotype relationships were studied by linear trend analysis stratified by sex. The rs9939609 A-allele was significantly associated with CRP levels in both genders (men, +21%, P = 0.002; women, +14%, P = 0.01 per A-allele). The association was attenuated, but remained statistically significant after additional adjustment for BMI, waist-to-hip ratio, and other potential confounding factors (men, +14%, P = 0.03; women, +12%, P = 0.02; per A-allele). Similar results were obtained when subjects with CRP levels higher then 10 mg/l were excluded. Our data provide preliminary evidence that the FTO rs9939609 T>A polymorphism contributes to variation in plasma CRP levels independently of obesity indices.

Metabolic syndrome and risk of incident diabetes: findings from the European Prospective Investigation into Cancer and Nutrition-Potsdam Study

BACKGROUND

Several aspects concerning the relationship between the metabolic syndrome and incident diabetes are incompletely understood including the magnitude of the risk estimate, potential gender differences in the associations between the metabolic syndrome and incident diabetes, the associations between the components of the metabolic syndrome and incident diabetes, and whether the metabolic syndrome provides additional prediction beyond its components. To shed light on these issues, we examined the prospective association between the metabolic syndrome defined by the National Cholesterol Education Program (NCEP) and International Diabetes Federation (IDF) and diabetes.

METHODS

We used data for 2796 men and women aged 35-65 years from the European Prospective Investigation into Cancer and Nutrition-Potsdam Study followed for an average of 6.9 years. This analysis employed a case-cohort design that included 697 participants who developed diabetes and 2099 participants who did not. Incident diabetes was identified on the basis of self-reports and verified by contacting the patient's attending physician.

RESULTS

The adjusted hazard ratio for the NCEP definition was 4.62 (95% confidence interval [CI]: 3.90-5.48) and that for the IDF definition was 4.59 (95% CI: 3.84-5.50). The adjusted hazard ratios for the NCEP but not IDF definition were higher for women than men. When participants who had no cardiometabolic abnormalities were used as the reference group for the NCEP definition, the adjusted hazard ratio for having 3 or more abnormalities increased to 22.50 (95% CI: 11.21-45.19). Of the five components, abdominal obesity and hyperglycemia were most strongly associated with incident diabetes.

CONCLUSION

In this study population, both definitions of the metabolic syndrome provided similar estimates of relative risk for incident diabetes. The increase in risk for participants with the metabolic syndrome according to the NCEP definition was very large when contrasted with the risk among those who had no cardiometabolic abnormalities.

Plasma fetuin-a levels and the risk of myocardial infarction and ischemic stroke

BACKGROUND

Fetuin-A, a protein almost exclusively secreted by the liver, induces insulin resistance and subclinical inflammation in rodents. Circulating fetuin-A levels are elevated in humans with metabolic syndrome and insulin resistance, conditions that are associated with increased risk of cardiovascular disease.

METHODS AND RESULTS

We investigated the association between fetuin-A levels and the risk of future myocardial infarction (MI) and ischemic stroke (IS) in a case-cohort study based on the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study comprising 27 548 middle-aged subjects of the general population. Fetuin-A levels were measured in plasma of 227 individuals who developed MI, in 168 who developed IS, and in 2198 individuals who remained free of cardiovascular events during a mean follow-up of 8.2+/-2.2 years. Individuals in the highest compared with the lowest quintile of plasma fetuin-A had significantly increased risks of MI (relative risk, 3.80; 95% confidence interval, 2.37 to 6.10; P for trend <0.0001) and IS (relative risk, 3.93; 95% confidence interval, 2.17 to 7.12; P for trend <0.0001) after adjustment for sex and age. Additional adjustment for smoking status, body mass index, waist circumference, alcohol consumption, educational attainment, physical activity, hypertension, diabetes mellitus, total and high-density lipoprotein cholesterol, and C-reactive protein only moderately attenuated these risks (MI: relative risk, 3.25; 95% confidence interval, 2.01 to 5.28; P for trend <0.0001; IS: relative risk, 3.78; 95% confidence interval, 2.06 to 6.94; P for trend <0.0001).

CONCLUSIONS

Our data provide evidence for a link between high plasma fetuin-A levels and an increased risk of MI and IS. Therefore, more research is warranted to determine the role of fetuin-A in the pathophysiology of cardiovascular disease.

Plasma resistin levels and risk of myocardial infarction and ischemic stroke

CONTEXT

Resistin is a hormone that has been linked to insulin resistance, inflammatory processes, and coronary heart disease in case-control studies; however, prospective data on the association between plasma resistin levels and future risk of cardiovascular disease are lacking.

OBJECTIVE

The objective of the study was to investigate the association between plasma resistin levels and risk of future myocardial infarction (MI) and ischemic stroke (IS) in a large prospective cohort.

METHODS

We investigated the association between plasma resistin levels and risk of MI and IS in a case-cohort design among 26,490 middle-aged subjects from the European Investigation into Cancer and Nutrition-Potsdam Study without history of MI or stroke at time of blood draw. Plasma resistin levels were measured in baseline blood samples of 139 individuals who developed MI, 97 who developed IS, and 817 individuals who remained free of cardiovascular events during a mean follow-up of 6 yr.

RESULTS

After multivariable adjustment for established cardiovascular risk factors including C-reactive protein, individuals in the highest compared with the lowest quartile of plasma resistin levels had a significantly increased risk of MI (relative risk 2.09; 95% confidence interval 1.01-4.31; P for trend = 0.01). In contrast, plasma resistin levels were not significantly associated with risk of IS (relative risk 0.94; 95% confidence interval 0.51-1.73; P for trend = 0.88).

CONCLUSION

Our data suggest that high plasma resistin levels are associated with an increased risk of MI but not with risk of IS. Further studies are needed to evaluate the predictive value of plasma resistin levels for cardiovascular disease.

Association analyses of GIP and GIPR polymorphisms with traits of the metabolic syndrome

Glucose-dependent insulinotropic polypeptide (GIP) stimulates insulin release via interaction with its pancreatic receptor (GIP receptor (GIPR)). GIP also acts as vasoactive protein. To investigate whether variations in GIP and GIPR genes are associated with risk factors of the metabolic syndrome we sequenced gene regions and identified two coding SNPs (GIP Ser103Gly, GIPR Glu354Gln) and one splice site SNP (GIP rs2291726) in 47 subjects. Interestingly, in silico analyses revealed that splice site SNP rs2291726 results in a truncated protein and classified GIPR variant Glu354Gln as a functional amino acid change. Association analyses were performed in a case-cohort study of incident cardiovascular disease (CVD) nested in the EPIC-Potsdam cohort. No significant associations between incident CVD and GIP Ser103Gly and rs2291726 were found. For GIPR Glu354Gln, we obtained a nominal association of heterozygous minor allele carrier with CVD in a codominant model adjusted for BMI, sex, and age (OR: 0.67, CI: 0.50-0.91, p = 0.01) or additional covariates of CVD (OR: 0.72, CI: 0.52-0.97, p = 0.03). In conclusion, we identified a common splice site mutation (rs2291726) of the GIP gene which results in a truncated protein and provide preliminary evidence for an association of the heterozygous GIPR Glu354Gln genotype with CVD.

Carbohydrate intake and incidence of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study

It remains unclear what long-term effects of substituting carbohydrates at the expense of protein or fat may have with regard to diabetes risk. Our objective was to evaluate carbohydrate intake in predicting type 2 diabetes using substitution models for fat and protein. We conducted a prospective cohort study of 9,702 men and 15,365 women aged 35-65 years and free of diabetes at baseline (1994-8) who were followed for incident type 2 diabetes until 2005. Dietary intake of macronutrients was estimated with a validated FFQ. We estimated the relative risk (RR) using Cox proportional hazards analysis. During 176,117 person-years of follow-up we observed 844 incident cases of physician-confirmed type 2 diabetes. After adjustment for age, BMI, waist circumference, potential lifestyle and dietary confounders, substituting 5 % of energy intake from total, saturated, or monounsaturated fat with carbohydrates was not associated with diabetes risk. In contrast, substituting carbohydrates for protein or PUFA was inversely related to diabetes risk (RR for 5 % energy substitution of protein 0.77 (95 % CI 0.64, 0.91); RR for PUFA 0.83 (95 % CI 0.70, 0.98)). These associations appeared to be similar for men and women, but gained statistical significance only among men for protein (RR 0.78 (95 % CI 0.61, 0.99)). Restricted cubic spline regression did not indicate non-linearity of these associations (P for non-linearity in full cohort was 0.353 and 0.349). In conclusion, a higher carbohydrate intake at the expense of protein and PUFA might be associated with decreased diabetes risk.

B Vitamin Plasma Levels and the Risk of Ischemic Stroke and Transient Ischemic Attack in a German Cohort

Background and Purpose— Data from prospective studies on the associations between B vitamin plasma levels and the risk of stroke are limited. We investigated the individual and combined effects of plasma folate, vitamin B12, and pyridoxal 5-phophate (PLP) levels on the risk of ischemic stroke and transient ischemic attack (TIA) in a large, prospective German cohort.

Methods— Incident cases of ischemic stroke or TIA were identified among 25 770 participants (age 35 to 65 years) of the European Prospective Investigation into Cancer and Nutrition-Potsdam Study during 6.0±1.5 years of follow-up. The present analysis is based on a case-cohort study comprising 779 subjects free from cardiovascular disease and 188 incident cases of cerebral ischemia (ischemic stroke or TIA). Multivariable Cox proportional-hazard models were applied to evaluate the association between B vitamin levels and risk of cerebral ischemia.

Results— Participants in the lowest tertile of vitamin B12 values were at increased risk of cerebral ischemia compared with subjects in the highest tertile; this was not observed, however, for either folate or PLP. In subgroup analyses, the relative risks were similar in magnitude for stroke and TIA. When various combinations of B vitamin tertile levels were analyzed, only combined low folate and vitamin B12 levels (relative risk, 2.24; 95% CI, 1.10 to 4.54) were significantly related to an increased risk of cerebrovascular ischemia.

Conclusions— Our data suggest that low vitamin B12 plasma levels, particularly in combination with low folate levels, increase the risk of cerebral ischemia. This effect may be mediated at least partly through elevations of homocysteine levels.

Association of prostaglandin E synthase 2 (PTGES2) Arg298His polymorphism with type 2 diabetes in two German study populations

CONTEXT

On the basis of its chromosomal localization and its role in the synthesis of the antilipolytic compound prostaglandin E(2), the prostaglandin E synthase 2 (PTGES2) is a candidate gene for type 2 diabetes.

OBJECTIVE

The aim of the present study was to investigate whether genetic variants in the PTGES2 gene are associated with type 2 diabetes.

RESULTS

Sequencing of the PTGES2 gene revealed one nonsynonymous coding single-nucleotide polymorphism (SNP) (Arg298His, rs13283456) and a previously unknown promoter SNP g.-417G>T. Both SNPs and additional haplotype tagging SNPs (rs884115, rs10987883, rs4837240) were genotyped in a nested case-control study of 192 incident type 2 diabetes subjects and 384 controls (European Prospective Investigation into Cancer and Nutrition-Potsdam). Carriers of the minor allele of Arg298His had a lower risk to develop the disease [odds ratio (OR) 0.63, 95% confidence interval (CI) 0.41-0.97, P = 0.04], compared with homozygous individuals with the common allele. The PTGES2 Arg298His polymorphism was reinvestigated in a population-based cross-sectional study (Cooperative Health Research in the Augsburg Region) consisting of 239 individuals with impaired glucose tolerance, 226 with type 2 diabetes, and 863 normoglycemic controls. In this study population, the Arg298His polymorphism was significantly associated with impaired glucose tolerance (OR 0.68, 95% CI 0.50-0.93, P = 0.007) and type 2 diabetes (OR 0.61, 95% CI 0.43-0.86, P = 0.004). A pooled analysis of data from both study populations revealed reduced risk of type 2 diabetes (OR 0.62, 95% CI 0.47-0.81, P = 0.0005) in PTGES2 298His allele carriers.

CONCLUSION

We obtained evidence from two Caucasian study populations that the His298-allele of PTGES2 Arg298His confers to reduced risk of type 2 diabetes.

A food pattern predicting prospective weight change is associated with risk of fatal but not with nonfatal cardiovascular disease

Recently, a food pattern predictive for prospective weight change was identified within the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort. Given the possible impact of weight change on cardiovascular disease (CVD) risk, we examined the association between the above mentioned food pattern and risk of CVD. The analyzed food pattern was defined by a high consumption of whole-grain bread, fruits, fruit juices, grain flakes and/or cereals, and raw vegetables, and a low consumption of processed meat, butter, high-fat cheese, margarine, and meat other than poultry. The associations between quartiles of the food pattern score and CVD morbidity and mortality were examined in 26,238 subjects of the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort using a Cox's Proportional Hazards model for competing risks. During 6.4 y of follow-up, 379 incident cases of CVD were identified, of which 68 were fatal events. The food pattern was not associated with risk of nonfatal CVD. After adjusting for cardiovascular risk factors, the hazard ratios for fatal CVD across increasing quartiles of the score were 1.00, 0.85, 0.31, and 0.47, respectively (P for trend = 0.016). The association of the food pattern with CVD risk differed between fatal and nonfatal events (P for difference = 0.05). These findings from a large German cohort indicate that a food pattern predicting prospective weight change may be associated with the risk of fatal CVD.

L-FABP T94A is associated with fasting triglycerides and LDL-cholesterol in women

To determine the possible role of the common FABP1 T94A polymorphism in modulating susceptibility to traits of the metabolic syndrome, we analysed a random sample of 826 subjects from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort. Multivariate adjusted linear trend regression analysis of metabolic, anthropometric and blood pressure variables in FABP1 T94A genotypes were performed in both genders. In women, a significant trend of higher plasma triglyceride (P=0.01) and LDL-cholesterol (P=0.02) concentrations were seen for A-allele carriers after adjustment for age, menopausal status, hormone intake and Apo E genotype. Because elevated triglyceride and cholesterol levels are important risk factors of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), we additionally analysed the association of the T94A variant and disease risks in two studies enrolling 220 incident CVD and 192 incident T2DM patients of the EPIC-Potsdam cohort. After adjusting for age, sex, BMI and other covariates, we found no association between FABP1 T94A and CVD or T2DM. In conclusion, our study provides evidence for an association of the FABP1 T94A polymorphism and fasting triglycerides and LDL-cholesterol levels in females. These results support previous findings in fenofibrate-treated individuals and thereby provide some additional indication of the functional relevance of the FABP1 T94A SNP in hepatic fatty acid and lipid metabolism in humans.

Potentially modifiable classic risk factors and their impact on incident myocardial infarction: results from the EPIC-Potsdam study

BACKGROUND

Prospective data on the importance of established risk factors for myocardial infarction in Germany are sparse.

DESIGN

The population-based cohort study European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam with 159 incident cases of myocardial infarction (120 men, 39 women) occurring among 26 954 participants (10 463 men, 16 491 women) during an average follow-up time of 4.6 years.

METHODS

We examined the classic, potentially modifiable risk factors smoking, hypertension, hyperlipidemia, diabetes mellitus, abdominal obesity, and sporting inactivity, both individually and in combination, by estimating their prevalence and their relative and population-attributable risks of incident myocardial infarction.

RESULTS

After adjusting for age, sex, educational attainment, alcohol intake, and the respective other classic risk factors the relative risks of myocardial infarction were 3.18 for smoking [95% confidence interval (CI) 2.31, 4.38], 1.84 for hypertension (95% CI 1.27, 2.65), 1.81 for sporting inactivity (95% CI 1.04, 3.15), 1.64 for diabetes (95% CI 1.05, 2.56), 1.62 for abdominal obesity (95% CI 1.03, 2.56), and 1.15 for hyperlipidemia (95% CI 0.84, 1.59). Participants with four or all five significant risk factors had an approximately 11.5-fold higher risk of the coronary event than participants with none or one risk factor. Altogether, 84.3% of myocardial infarctions in the study population were attributable to the presence of the five risk factors smoking, hypertension, diabetes, sporting inactivity, and abdominal obesity.

CONCLUSION

The majority of myocardial infarctions in the EPIC-Potsdam cohort were explainable by potentially modifiable classic risk factors. Therefore, besides efforts to investigate novel coronary risk factors, the prevention of coronary disease should focus on strategies to reduce the prevalence of established risk factors.

Comparison of two statistical approaches to predict all-cause mortality by dietary patterns in German elderly subjects

Dietary patterns are comprehensive variables of dietary intake appropriate to model the complex exposure in nutritional research. The objectives of this study were to identify dietary patterns by applying two statistical methods, principal component analysis (PCA) and reduced rank regression (RRR), and to assess their ability to predict all-cause mortality. Motivated by previous studies we chose percentages of energy from different macronutrients as response variables in the RRR analysis. We used data from 9356 German elderly subject enrolled in the European Prospective Investigation into Cancer and Nutrition study. The first RRR pattern, subjects which explained 30·8 % of variation in energy sources and especially much variation in intake of saturated fat, monounsaturated fat and carbohydrates was a significant predictor of all-cause mortality. The pattern score had high positive loadings in all types of meat, butter, sauces and eggs, and was inversely associated with bread and fruits. After adjustment for other known risk factors, the relative risks from the lowest to highest quintiles of the first RRR pattern score were 1·0, 1·01, 0·96, 1·32, 1·61 (P for trend: 0·0004). In contrast, the first two PCA patterns explaining 19·7 % of food intake variation but only 7·0 % of variation in energy sources were not related to mortality. These results suggest that variation in macronutrients is meaningful for mortality and that the RRR method is more appropriate than the classic PCA method to identify dietary patterns relevant to mortality.

Joint effects of risk factors for stroke and transient ischemic attack in a German population

BACKGROUND

Single, modifiable risk factors for stroke have extensively been studied. In contrast, differences of their combined effects among stroke and transitoy ischemic attack (TIA) have been rarely investigated. The aim of the present study was to assess single and joint effects of risk factors on the incidence of stroke and TIA and to compare their magnitudes in a large population-based German cohort.

METHODS

Incident cases of stroke and TIA were identified among 25,538 participants (aged 35-65 at baseline) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study. Relative risks for stroke and TIA related to modifiable risk factors were estimated using Cox proportional hazard models.

RESULTS

During 4.3 years of follow-up 100 stroke cases and 112 TIA cases occurred. Incidences of stroke and TIA were 91.7 and 102.7 per 100,000 person-years, respectively. Relative risks for ischemic stroke (RR 5.12, 95% CI 1.49-17.6, p for trend<0.0001) and for TIA (RR 3.08, 95% CI 1.00-9.44, p for trend<0.024) were highest among participants having 4 or 5 modifiable risk factors. 58.5% of ischemic strokes and 26.2% of TIA cases were attributable to the 5 risk factors hypertension, diabetes mellitus, high alcohol consumption, hyperlipidemia, and smoking.

CONCLUSION

Our data indicate that classical risk factors may explain almost 60% of ischemic stroke but only one in four TIA cases. Analysing potential differences of known risk factors between ischemic stroke and TIAs and the identification of other determinants of ischemic attacks are important steps to better explain the burden of stroke.

Dietary intake of folate equivalents and risk of myocardial infarction in the European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam study

Objective

To assess the relationship between intake of dietary folate equivalents and risk of myocardial infarction in a German cohort.

Design

Intake of dietary folate equivalents was assessed by a validated food-frequency questionnaire. Cox proportional hazard models were used to evaluate the association between intake of dietary folate equivalents and risk of myocardial infarction.

Setting

The European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam cohort, Germany.

Subjects

Subjects were 22 245 apparently healthy non-users of vitamin supplements aged 35–64 years.

Results

During 4.6 years of follow-up, 129 incident cases of myocardial infarction were identified. Compared with intake below the median (103 μg), higher intake of dietary folate equivalents was associated with a multivariate-adjusted hazard ratio (HR) of 0.57 (95% confidence interval (CI) 0.36–0.91). The inverse association of folate intake and myocardial infarction risk was stronger in participants with an ethanol intake equal to or above the sex-specific median (HR = 0.37, 95% CI 0.18–0.79) and attenuated in those with a low ethanol intake (HR = 0.67, 95% CI 0.37–1.22).

Conclusion

An increased intake of dietary folate equivalents was observed to be associated with decreased risk of myocardial infarction in a German study population, pointing towards the importance of folate intake with respect to primary prevention of myocardial infarction.

Putative association between a new polymorphism in exon 3 (Arg109Cys) of the pancreatic colipase gene and type 2 diabetes mellitus in two independent Caucasian study populations

The protein encoded by the pancreatic colipase (CLPS) gene is an essential cofactor needed by pancreatic triglyceride lipase (PNLIP) for efficient dietary lipid hydrolysis. Since the inhibition of lipase activity was shown to reduce the incidence of type 2 diabetes mellitus, we tested the hypothesis that genetic variations in the CLPS and PNLIP genes are associated with type 2 diabetes; 47 unrelated subjects were screened for polymorphisms of the CLPS and PNLIP genes. A nested-case control study of 192 incident type 2 diabetes subjects and 384 sex- and age-matched controls taken from the European Prospective Investigation into Cancer and Nutrition Potsdam Cohort (EPIC) was employed for association studies. The Metabolic Intervention Cohort Kiel (MICK) consisting of 716 males was used for verification. A novel putative functional polymorphism (Arg109Cys) was identified in the CLPS gene. The frequencies of the Arg/Cys genotype were 2.6% in EPIC and 2.2% in MICK study subjects. No homozygotes for the Cys/Cys genotype were found in either study population. Logistic regression analysis showed a statistically significant association of the Arg/Cys genotype with an increased risk of type 2 diabetes. The odds ratios estimated by the model were 3.75 (95%CI = 1.13-12.49, p = 0.03) in EPIC and 4.86 (95%CI = 1.13-20.95, p = 0.03) in MICK. No comparable associations were found with other traits of the insulin-resistance syndrome (e. g.; body mass index, waist to hip ratio). In conclusion, we obtained evidence in two German Caucasian study populations that the variant of the rare CLPS Arg109Cys polymorphism might contribute to increased susceptibility of type 2 diabetes.

The relation between dietary protein, calcium and bone health in women: results from the EPIC-Potsdam cohort

BACKGROUND/AIMS

The role of dietary protein in bone health is controversial. The objective of the present study was to examine the association between protein intake, dietary calcium, and bone structure measured by broadband ultrasound attenuation (BUA).

METHODS

Our analysis includes 8,178 female study participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) Potsdam Study. Ultrasound bone measurements were performed on the right os calcis, and BUA was determined. Dietary intake was assessed by a standardized food frequency questionnaire. We applied linear regression models to estimate the association between dietary protein and BUA.

RESULTS

After multivariate adjustment, high intake of animal protein was associated with decreased BUA values (beta = -0.03; p = 0.010) whereas high vegetable protein intake was related to an increased BUA (beta = 0.11; p = 0.007). The effect of dietary animal protein on BUA was modified by calcium intake.

CONCLUSION

High consumption of protein from animal origin may be unfavourable, whereas a higher vegetable protein intake may be beneficial for bone health. Our results strengthen the hypothesis that high calcium intake combined with adequate protein intake based on a high ratio of vegetable to animal protein may be protective against osteoporosis.

A homocysteine metabolism-related dietary pattern and the risk of coronary heart disease in two independent German study populations

A biomarker profile of high folate and vitamin B-12 and low plasma homocysteine concentrations reduces the risk of coronary heart disease (CHD) and may be linked to diet. The objectives of the present study were to identify a food pattern related to these biomarkers and to examine its association with CHD risk. Dietary patterns related to biomarker plasma concentrations were constructed from data obtained in the Coronary Risk Factors for Atherosclerosis in Women (CORA) Study (200 cases; 255 controls) using the reduced rank regression statistical method. Risks for CHD with relation to the identified pattern were estimated in the CORA study and in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study with 157 cases of incident myocardial infarction among 26,795 participants. In these 2 German study populations, whole-grain bread, fresh fruit, olive oil, mushrooms, cruciferous vegetables, wine, and nuts contributed the most positively and fried potatoes the most negatively to a dietary pattern that was directly associated with both plasma folate and vitamin B-12 concentrations, but inversely with plasma homocysteine. Multivariate-adjusted relative risks for CHD across increasing quintiles of the food pattern score were 1.0, 0.55, 0.52, 0.58, 0.39 (P for trend = 0.05) in the case-control sample and 1.0, 0.95, 0.75, 0.56, 0.72 (P for trend = 0.041) in the prospective study. The combination of a high intake of whole-grain bread, fresh fruit, olive oil, mushrooms, cruciferous vegetables, wine, and nuts with a low intake of fried potatoes was associated with a favorable biomarker profile of homocysteine metabolism and reduced risk of CHD.