Wolfgang Rathmann

Cohort Profile: The Study of Health in Pomerania

Henry Volzke, y Dietrich Alte,1y Carsten Oliver Schmidt, Dorte Radke, Roberto Lorbeer, Nele Friedrich, Nicole Aumann, Katharina Lau, Michael Piontek, Gabriele Born, Christoph Havemann, Till Ittermann, Sabine Schipf, Robin Haring, Sebastian E Baumeister, Henri Wallaschofski, Matthias Nauck, Stephanie Frick, Andreas Arnold, Michael Junger, Julia Mayerle, Matthias Kraft, Markus M Lerch, Marcus Dorr, Thorsten Reffelmann, Klaus Empen, Stephan B Felix, Anne Obst, Beate Koch, Sven Glaser, Ralf Ewert, Ingo Fietze, Thomas Penzel, Martina Doren, Wolfgang Rathmann, Johannes Haerting, Mario Hannemann, Jurgen Ropcke, Ulf Schminke, Clemens Jurgens, Frank Tost, Rainer Rettig, Jan A Kors, Saskia Ungerer, Katrin Hegenscheid, Jens-Peter Kuhn, Julia Kuhn, Norbert Hosten, Ralf Puls, Jorg Henke, Oliver Gloger, Alexander Teumer, Georg Homuth, Uwe Volker, Christian Schwahn, Birte Holtfreter, Ines Polzer, Thomas Kohlmann, Hans J Grabe, Dieter Rosskopf, Heyo K Kroemer, Thomas Kocher, Reiner Biffar,17,y Ulrich John20y and Wolfgang Hoffmann1y

High prevalence of undiagnosed diabetes mellitus in Southern Germany: Target populations for efficient screening. The KORA survey 2000

Aims/hypothesisTo estimate the prevalence of undiagnosed diabetes mellitus, impaired glucose tolerance (IGT) and impaired fasting glucose (IFG), and their relations with cardiovascular risk factors in the general population aged 55 to 74 years in Southern Germany.MethodsOral glucose tolerance tests were carried out in a random sample of 1353 subjects aged 55 to 74 years participating in the KORA (Cooperative Health Research in the Region of Augsburg) Survey 2000. Prevalences of glucose tolerance categories (1999 WHO criteria) were adjusted for sample probabilities. The numbers needed to screen (NNTS) to identify one person with undiagnosed diabetes were estimated from age-adjusted logistic regression models.ResultsSample design-based prevalences of known and unknown diabetes, IGT, and IFG were 9.0%, 9.7%, 16.8%, 9.8% in men, and 7.9%, 6.9%, 16.0%, 4.5% in women, respectively. In both sexes, participants with undiagnosed diabetes had higher BMI, waist circumference, systolic blood pressure, triglycerides, uric acid, and lower HDL-cholesterol than normoglycaemic subjects. A combination of abdominal adiposity, hypertension, and parental diabetes in men resulted in a NNTS of 2.9 (95%CI: 2.0–4.6). In women, the combination of increased triglycerides, hypertension and parental diabetes history yielded a NNTS of 3.2 (95%CI: 2.2–5.1).Conclusion/interpretationAbout 40% of the population aged 55 to 74 years in the Augsburg region have disturbed glucose tolerance or diabetes. Half of the total cases with diabetes are undiagnosed. Cardiovascular risk factors worsen among glucose tolerance categories, indicating the need for screening and prevention. Screening for undiagnosed diabetes could be most efficient in individuals with abdominal adiposity (men), hypertriglyceridaemia (women), hypertension, and parental diabetes history.

Novel biomarkers for pre-diabetes identified by metabolomics

Type 2 diabetes (T2D) can be prevented in pre‐diabetic individuals with impaired glucose tolerance (IGT). Here, we have used a metabolomics approach to identify candidate biomarkers of pre‐diabetes. We quantified 140 metabolites for 4297 fasting serum samples in the population‐based Cooperative Health Research in the Region of Augsburg (KORA) cohort. Our study revealed significant metabolic variation in pre‐diabetic individuals that are distinct from known diabetes risk indicators, such as glycosylated hemoglobin levels, fasting glucose and insulin. We identified three metabolites (glycine, lysophosphatidylcholine (LPC) (18:2) and acetylcarnitine) that had significantly altered levels in IGT individuals as compared to those with normal glucose tolerance, with P‐values ranging from 2.4 × 10−4 to 2.1 × 10−13. Lower levels of glycine and LPC were found to be predictors not only for IGT but also for T2D, and were independently confirmed in the European Prospective Investigation into Cancer and Nutrition (EPIC)‐Potsdam cohort. Using metabolite–protein network analysis, we identified seven T2D‐related genes that are associated with these three IGT‐specific metabolites by multiple interactions with four enzymes. The expression levels of these enzymes correlate with changes in the metabolite concentrations linked to diabetes. Our results may help developing novel strategies to prevent T2D.

Mortality in Diabetic Patients with Cardiovascular Autonomic Neuropathy

Cardiovascular autonomic diabetic neuropathy (CADN) may carry an increased risk of mortality. However, in previous studies the prognosis of patients with CADN seemed to be influenced by life‐threatening macro‐ and microvascular complications which had already been present at the start of the study period. Between 1981 and 1983, 1015 diabetic patients have been examined for CADN (abnormal heart rate variation at rest and during deep respiration) at the Diabetes Research Institute, Düsseldorf. Thirty‐five patients (28 with Type 1 diabetes, 7 with Type 2 diabetes) with CADN have been retrospectively recruited and reviewed 8 years later and compared with 35 patients without CADN who were matched for sex, age, and duration of diabetes. Exclusion criteria for entry into the study included severe micro‐ or macrovascular complications, such as proliferative retinopathy, proteinuria or symptomatic coronary artery disease. During the 8‐year observation period, 8 patients with CADN and 1 patient without CADN died. The survival rate estimates steadily declined in patients with CADN over the whole period studied. The 8‐year survival rate estimate in patients with CADN was 77 % compared with 97 % in those with normal autonomic function (p < 0.05). Deaths were mainly due to macrovascular diseases (n = 3) and sudden unexpected deaths (n = 3). One patient with CADN died after an episode of severe hypoglycaemia. Among the deceased patients, coefficient of variation of R‐R intervals during deep breathing was significantly reduced when compared with those who survived (1.04 ± 0.5 % vs 1.87 ± 1.0 %; p < 0.05), and symptoms of autonomic neuropathy (orthostatic hypotension, gastroparesis, gustatory sweating) were more frequent (7/8 vs 10/27 patients). The mean QTc interval was not different between the groups. These results suggest a relatively poor prognosis of patients with CADN in the absence of clinically detectable micro‐ and macrovascular complications.

Prevalence of Polyneuropathy in Pre-Diabetes and Diabetes Is Associated With Abdominal Obesity and Macroangiopathy : The MONICA/KORA Augsburg Surveys S2 and S3

OBJECTIVE—It is controversial whether there is a glycemic threshold above which polyneuropathy develops and which are the most important factors associated with polyneuropathy in the general population. The aim of this study was to determine the prevalence and risk factors of polyneuropathy in subjects with diabetes, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or normal glucose tolerance (NGT). RESEARCH DESIGN AND METHODS—Subjects with diabetes (n = 195) and control subjects matched for age and sex (n = 198) from the population-based MONICA (Monitoring Trends and Determinants on Cardiovascular Diseases)/KORA (Cooperative Research in the Region of Augsburg) Augsburg Surveys 1989/1990 (S2) and 1994/1995 (S3) aged 25–74 years were contacted again and assessed in 1997/1998 by the Michigan Neuropathy Screening Instrument using a score cut point >2. An oral glucose tolerance test was performed in the control subjects. RESULTS—Among the control subjects, 46 (23.2%) had IGT, 71 (35.9%) had IFG, and 81 had NGT. The prevalence of polyneuropathy was 28.0% in the diabetic subjects, 13.0% in those with IGT, 11.3% in those with IFG, and 7.4% in those with NGT (P ≤ 0.05 for diabetes vs. NGT, IFG, and IGT). In the entire population studied (n = 393), age, waist circumference, and diabetes were independent factors significantly associated with polyneuropathy, whereas in the diabetic group polyneuropathy was associated with age, waist circumference, and peripheral arterial disease (PAD) (all P < 0.05). CONCLUSIONS—The prevalence of polyneuropathy is slightly increased in individuals with IGT and IFG compared with those with NGT. The association with waist circumference and PAD suggests that the latter and abdominal obesity may constitute important targets for strategies to prevent diabetic polyneuropathy.

Relations of Hyperuricemia with the Various Components of the Insulin Resistance Syndrome in Young Black and White Adults: The CARDIA Study

PURPOSE To assess the association of hyperuricemia with the various components of the Insulin Resistance Syndrome (IRS) in a biracial cohort of young adults. METHODS Cross-sectional study in 4053 young black and white adults aged 18-30 years from the Coronary Artery Risk Development in Young Adults (CARDIA) study. RESULTS Body mass index (BMI), fasting insulin, and triglycerides were significantly higher, and high density lipoprotein (HDL)-cholesterol lower in subjects with hyperuricemia (uric acid > or = 7.0 mg/dl in males; > or = 6.0 mg/dl in females) (all p < 0.001). BMI showed the strongest positive correlation with uric acid among the IRS components. Significant associations of hyperuricemia with these risk factors were observed in all sex-race groups, which persisted after controlling for possible confounders including age, education, physical activity, smoking, alcohol intake, oral contraceptive use, and creatinine. Further adjustment for BMI and/or waist-to-hip ratio caused a large decrease in the strength of the associations. Adjustment for insulin also lead to decreases; however, the influence of fasting insulin appeared weaker than obesity. Even after controlling for obesity, insulin, and the other components of the IRS, male subjects in both races in the upper tertile of triglycerides were still more likely to have hyperuricemia. CONCLUSIONS The association of hyperuricemia with most aspects of the IRS may result predominantly from their covariation with adiposity and secondarily with insulin level. Elevated triglyceride level seems to have an independent relationship with hyperuricemia in males. The relationship between hyperuricemia and cardiovascular disease observed in previous studies may be secondary to its association with the IRS.

Traffic-Related Air Pollution and Incident Type 2 Diabetes: Results from the SALIA Cohort Study

Background Cross-sectional and ecological studies indicate that air pollution may be a risk factor for type 2 diabetes, but prospective data are lacking. Objective We examined the association between traffic-related air pollution and incident type 2 diabetes. Design Between 1985 and 1994, cross-sectional surveys were performed in the highly industrialized Ruhr district (West Germany); a follow-up investigation was conducted in 2006 using data from the Study on the Influence of Air Pollution on Lung, Inflammation and Aging (SALIA) cohort. Participants 1,775 nondiabetic women who were 54–55 years old at baseline participated in both baseline and follow-up investigations and had complete information available. Materials and Methods Using questionnaires, we assessed 16-year incidence (1990–2006) of type 2 diabetes and information about covariates. Complement factor C3c as marker for subclinical inflammation was measured at baseline. Individual exposure to traffic-related particulate matter (PM) and nitrogen dioxide was determined at different spatial scales. Results Between 1990 and 2006, 87 (10.5%) new cases of diabetes were reported among the SALIA cohort members. The hazards for diabetes were increased by 15–42% per interquartile range of PM or traffic-related exposure. The associations persisted when different spatial scales were used to assess exposure and remained robust after adjusting for age, body mass index, socioeconomic status, and exposure to several non–traffic-related sources of air pollution. C3c was associated with PM pollution at baseline and was a strong independent predictor of incident diabetes. Exploratory analyses indicated that women with high C3c blood levels were more susceptible for PM-related excess risk of diabetes than were women with low C3c levels. Conclusions Traffic-related air pollution is associated with incident type 2 diabetes among elderly women. Subclinical inflammation may be a mechanism linking air pollution with type 2 diabetes. Relevance to clinical practice Our study identifies traffic-related air pollution as a novel and potentially modifiable risk factor of type 2 diabetes.

Vitamin D and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from Europe and the United States

Objective To investigate the association between serum 25-hydroxyvitamin D concentrations (25(OH)D) and mortality in a large consortium of cohort studies paying particular attention to potential age, sex, season, and country differences. Design Meta-analysis of individual participant data of eight prospective cohort studies from Europe and the US. Setting General population. Participants 26 018 men and women aged 50-79 years Main outcome measures All-cause, cardiovascular, and cancer mortality. Results 25(OH)D concentrations varied strongly by season (higher in summer), country (higher in US and northern Europe) and sex (higher in men), but no consistent trend with age was observed. During follow-up, 6695 study participants died, among whom 2624 died of cardiovascular diseases and 2227 died of cancer. For each cohort and analysis, 25(OH)D quintiles were defined with cohort and subgroup specific cut-off values. Comparing bottom versus top quintiles resulted in a pooled risk ratio of 1.57 (95% CI 1.36 to 1.81) for all-cause mortality. Risk ratios for cardiovascular mortality were similar in magnitude to that for all-cause mortality in subjects both with and without a history of cardiovascular disease at baseline. With respect to cancer mortality, an association was only observed among subjects with a history of cancer (risk ratio, 1.70 (1.00 to 2.88)). Analyses using all quintiles suggest curvilinear, inverse, dose-response curves for the aforementioned relationships. No strong age, sex, season, or country specific differences were detected. Heterogeneity was low in most meta-analyses. Conclusions Despite levels of 25(OH)D strongly varying with country, sex, and season, the association between 25(OH)D level and all-cause and cause-specific mortality was remarkably consistent. Results from a long term randomised controlled trial addressing longevity are being awaited before vitamin D supplementation can be recommended in most individuals with low 25(OH)D levels.

Stratifying Type 2 Diabetes Cases by BMI Identifies Genetic Risk Variants in LAMA1 and Enrichment for Risk Variants in Lean Compared to Obese Cases

Common diseases such as type 2 diabetes are phenotypically heterogeneous. Obesity is a major risk factor for type 2 diabetes, but patients vary appreciably in body mass index. We hypothesized that the genetic predisposition to the disease may be different in lean (BMI<25 Kg/m2) compared to obese cases (BMI≥30 Kg/m2). We performed two case-control genome-wide studies using two accepted cut-offs for defining individuals as overweight or obese. We used 2,112 lean type 2 diabetes cases (BMI<25 kg/m2) or 4,123 obese cases (BMI≥30 kg/m2), and 54,412 un-stratified controls. Replication was performed in 2,881 lean cases or 8,702 obese cases, and 18,957 un-stratified controls. To assess the effects of known signals, we tested the individual and combined effects of SNPs representing 36 type 2 diabetes loci. After combining data from discovery and replication datasets, we identified two signals not previously reported in Europeans. A variant (rs8090011) in the LAMA1 gene was associated with type 2 diabetes in lean cases (P = 8.4×10−9, OR = 1.13 [95% CI 1.09–1.18]), and this association was stronger than that in obese cases (P = 0.04, OR = 1.03 [95% CI 1.00–1.06]). A variant in HMG20A—previously identified in South Asians but not Europeans—was associated with type 2 diabetes in obese cases (P = 1.3×10−8, OR = 1.11 [95% CI 1.07–1.15]), although this association was not significantly stronger than that in lean cases (P = 0.02, OR = 1.09 [95% CI 1.02–1.17]). For 36 known type 2 diabetes loci, 29 had a larger odds ratio in the lean compared to obese (binomial P = 0.0002). In the lean analysis, we observed a weighted per-risk allele OR = 1.13 [95% CI 1.10–1.17], P = 3.2×10−14. This was larger than the same model fitted in the obese analysis where the OR = 1.06 [95% CI 1.05–1.08], P = 2.2×10−16. This study provides evidence that stratification of type 2 diabetes cases by BMI may help identify additional risk variants and that lean cases may have a stronger genetic predisposition to type 2 diabetes.

Meta-Analysis and a Large Association Study Confirm a Role for Calpain-10 Variation in Type 2 Diabetes Susceptibility

To the Editor: Variation in the calpain-10 gene (CAPN10 [MIM 605286]) was recently linked and associated with type 2 diabetes mellitus (T2DM) susceptibility (Horikawa et al. 2000). The initial linkage of T2DM to chromosome 2 was found in a population of Mexican Americans from Starr County, Texas (Hanis et al. 1996). Specific combinations of three intronic variants, designated “SNP-43,” “SNP-19,” and “SNP-63,” that capture most of the haplotype diversity at CAPN10 were associated with a three-fold increased risk of T2DM in this population and could account for the observed linkage (Horikawa et al. 2000). Subsequent association and linkage studies of these three polymorphisms in other populations have produced conflicting results, with association being observed in some populations (Baier et al. 2000 [Pima Indian]; Cassell et al. 2002 [South Indian]; Garant et al. 2002 [African American]; Malecki et al. 2002 [Polish]; Orho-Melander et al. 2002 [Finnish/Botnia]), but not others (Evans et al. 2001 [British]; Hegele et al. 2001 [Oji-Cree Indians]; Tsai et al. 2001 [Samoan]; Xiang et al. 2001 [Chinese]; Daimon et al. 2002 [Japanese]; Elbein et al. 2002 [whites from Utah]; Fingerlin et al. 2002 [Finnish]; Rasmussen et al. 2002 [Danish and Swedish]; Horikawa et al. 2003 [Japanese]). We previously reported that another variant, SNP-44 (designated “CAPN10-g4841T→C”; minor allele frequency 16%), located in intron 3 and 11 bp from SNP-43, was independently associated with T2DM in whites from the United Kingdom (Evans et al. 2001). Further studies have provided tentative support for a role of SNP-44 in T2DM and related traits: associations with polycystic ovary syndrome (Gonzalez et al. 2002) and with measures of oral glucose tolerance (Wang et al. 2002; Tschritter et al. 2003) have been reported. Functional studies suggest that SNP-44 is located in an enhancer element and might affect CAPN10 expression (Horikawa et al. 2000). Also, in the U.K., German, Japanese, and South Indian populations, SNP-44 is in perfect linkage disequilibrium (r2=1) with a missense mutation Thr504Ala (SNP-110) and two polymorphisms in the 5′-UTR (SNP-134 and SNP-135) (Evans et al. 2001; Cassell et al. 2002; Y. Horikawa and P. E. Schwarz, unpublished data). To assess the association of SNP-44 with T2DM more comprehensively, we performed a meta-analysis of all published SNP-44/T2DM association study data. To identify all relevant published studies, we searched PubMed using the keywords “calpain 10,” “diabetes,” “44,” “SNP 44,” “CAPN10,” and “type 2,” in different combinations. When necessary, authors were contacted to obtain exact genotype numbers, so that precise odds ratios (ORs) from each study could be calculated. Our search identified 10 published case/control studies, consisting of 3,303 subjects. The studies were spread across a number of ethnic groups: British (three studies, Evans et al. 2001); Chinese (Wang et al. 2002); Japanese (Daimon et al. 2002; Horikawa et al. 2003); Finnish/Botnia (two studies, Orho-Melander et al. 2002); South Indian (Cassell et al. 2002); and Mexican American (Horikawa et al. 2000). The frequency of the T2DM-associated SNP-44 C allele (allele 2) ranged from 6% in Mexican Americans to 25% in the Botnia I control population. There was no evidence for OR heterogeneity (Q test P=.27), and, although these studies are only a small sample from the many existing T2DM genetic resources, a funnel-plot analysis (Egger et al. 1997) suggested an absence of publication bias (P=.44). A Mantel-Haenszel meta-analysis of these studies showed that the C allele was associated with increased risk of T2DM (OR 1.17 [1.02–1.34], P=.02). Three transmission/disequilibrium tests (TDT) had been performed (Evans et al. 2001; Cassell et al. 2002; Orho-Melander et al. 2002). The combined TDT results demonstrated that the C allele was significantly overtransmitted (117 transmitted vs. 77 not transmitted, P=.004) from heterozygous parents to diabetic offspring. Although this result cannot be considered independent replication, as proband data was included in the case/control meta-analysis from two of the TDT studies (Evans et al. 2001; Cassell et al. 2002), it provides evidence that the association is not due to population stratification. Of the 10 studies in the meta-analysis, only 1 reported a significant (P<.05) association (Evans et al. 2001). However, these studies were small and the mean power to detect an OR of 1.17 at P<.05 was ∼11% (range 5%–14%). In the context of genetic association studies, which test many polymorphisms in numerous candidate genes, a P value of .02 can only be considered evidence suggestive of a real association. We therefore genotyped SNP-44 in an additional 4,213 subjects: 3,274 white European subjects from four case/control studies (one British, two German, and one Czech); 691 Japanese subjects from two case/control studies; and 248 Mexican (mestizo) subjects from Mexico City and Orizaba City from one case/control study. Overall, this provided 2,056 subjects with T2DM and 2,157 controls, and a power of ∼80% to detect an OR of 1.17. Clinical details of the study subjects are presented in table 1; further details are available as supplementary information from the authors. All studies were approved by the relevant ethics committee, and all subjects gave their informed consent. Table 1 Clinical Characteristics of Subjects in Study[Note] When all the studies were combined, there was no evidence for between-studies OR heterogeneity (Q test P=.23); a Mantel-Haenszel fixed-effects model was therefore used for subsequent analysis. Meta-analysis of the new studies gave an OR for the SNP-44 C allele of 1.18 (1.04–1.34), P=.01 (fig. 1). A combined meta-analysis of all previously published data and our new data gave an OR of 1.17 (1.07–1.29), P=.0007. All study populations were in Hardy-Weinberg equilibrium except the T2DM cohort of Horikawa et al. 2003 (P=.005) and the control population of the third Japanese study (P=.02). Although these deviations may be due to random fluctuation and multiple-hypothesis testing, they contributed a large amount to heterogeneity (27% of the Q statistic); excluding these studies, the SNP-44 C allele OR for the new studies was 1.23 (1.07–1.40), P=.003; the overall OR was 1.19 (1.08–1.31), P=.0005. This OR is of similar magnitude to that of E23K (Gloyn et al. 2003; Love-Gregory et al. 2003; Nielsen et al. 2003) and Pro12Ala (Altshuler et al. 2000), the other common variants confirmed as T2DM-susceptibility polymorphisms. An OR of 1.17 is low and may help explain why there is little evidence for linkage of the CAPN10 region to T2DM in most populations. The haplotypes responsible for the CAPN10 linkage seen in the Mexican American population were associated with a higher T2DM OR (∼3.0) and were more likely to be detected by linkage analysis (Horikawa et al. 2000). These haplotypes are less common in other populations. Figure 1 Mantel-Haenszel OR meta-analysis plot (fixed effects) for SNP-44 association with T2DM. Point estimates and 95% CLs for each previously published, new, and combined case/control study. SNP-44 is in perfect linkage disequilibrium (r2=1) with the missense mutation, Thr504Ala, and two SNPs (SNP-134 and SNP-135) in the 5′-UTR and therefore may not be the causal variant. Further haplotype and functional analyses are required to confirm which of these polymorphisms contribute to T2DM susceptibility. In conclusion, our results have confirmed that a CAPN10 haplotype defined by the SNP-44 polymorphism predisposes to T2DM. Meta-analyses of published genetic associations, combined with large replication studies, are a powerful approach to detecting susceptibility variants in common disease.