Independent and opposite associations of serum levels of omentin-1 and adiponectin with increases of glycaemia and incident type 2 diabetes in an older population: KORA F4/FF4 study

OBJECTIVE

Cross-sectional studies found that higher levels of the novel adipokine omentin-1 were associated with higher adiponectin and lower levels of risk factors for type 2 diabetes, but its relevance for incident type 2 diabetes is currently not understood. Therefore this study investigated whether serum omentin-1 was associated with changes in glycaemia and incident type 2 diabetes independently of adiponectin.

DESIGN AND METHODS

The study was based on participants aged 62-81 years from the population-based Cooperative Health Research in the Region of Augsburg (KORA) F4/FF4 cohort. Associations of baseline serum levels of omentin-1 and adiponectin with changes in glycaemia were assessed in 471 non-diabetic participants, and associations between both adipokines and incident type 2 diabetes were assessed in 76 cases and 430 non-cases (follow-up time 6.5 years). Multivariable linear and logistic regression models were adjusted for multiple potential confounders.

RESULTS

Higher serum levels of omentin-1 were associated with increases in fasting glucose, 2-h glucose and HbA1c (all P < 0.001) and with incident type 2 diabetes (adjusted odds ratio (OR) (95% CI): 1.40 (1.03; 1.90) per s.d. of log₂-transformed omentin-1; P = 0.032). These associations were independent from adiponectin levels, which showed associations with changes in glycaemia and risk of type 2 diabetes in the opposite direction. We found no statistically significant interactions of omentin-1 with adiponectin or sex in the association with incident type 2 diabetes (all P > 0.1).

CONCLUSIONS

Systemic levels of omentin-1 were positively associated with increases in glycaemia and incident type 2 diabetes in this older population. These associations were independent of potential confounders including adiponectin.

Plasma Concentrations of Afamin Are Associated With Prevalent and Incident Type 2 Diabetes: A Pooled Analysis in More Than 20,000 Individuals

OBJECTIVE

The human vitamin E-binding glycoprotein afamin is primarily expressed in the liver and has been associated with prevalent and incident metabolic syndrome. These data were in line with observations in transgenic mice. We thus investigated whether afamin concentrations are associated with prediabetes, type 2 diabetes, and insulin resistance (IR).

RESEARCH DESIGN AND METHODS

Individual-level baseline (n = 20,136) and follow-up data (n = 14,017) of eight prospective cohort studies were investigated. Study-level data were combined using random-effects meta-analyses. Main outcomes were prevalent and incident type 2 diabetes, prediabetes, and IR. Discrimination and reclassification of participants was analyzed for incident type 2 diabetes.

RESULTS

Mean afamin concentrations between studies ranged from 61 to 73 mg/L. The eight studies included 1,398 prevalent and 585 incident cases of type 2 diabetes. Each increase of afamin by 10 mg/L was associated with prevalent type 2 diabetes (odds ratio [OR] 1.19 [95% CI 1.12-1.26], P = 5.96 × 10^-8). Afamin was positively associated with IR assessed by HOMA-IR (β 0.110 [95% CI 0.089-0.132], P = 1.37 × 10^-23). Most importantly, afamin measured at baseline was an independent predictor for 585 incident cases of type 2 diabetes (OR 1.30 [95% CI 1.23-1.38], P = 3.53 × 10^-19) and showed a significant and valuable gain in risk classification accuracy when added to this extended adjustment model.

CONCLUSIONS

This pooled analysis in >20,000 individuals showed that afamin is strongly associated with IR, prevalence, and incidence of type 2 diabetes independent of major metabolic risk factors or parameters. Afamin might be a promising novel marker for the identification of individuals at high risk for the development of type 2 diabetes.

Male sex and poverty predict abrupt health decline: Deficit accumulation patterns and trajectories in the KORA-Age cohort study

Ageing individuals differ both in their deficit accumulation (DA) trajectories and resulting DA patterns (improvement, stability, gradual or abrupt decline). This heterogeneity is still incompletely understood. The objectives of this study were thus to identify determinants of DA trajectories and DA patterns in people aged 65 and older. Data originates from the 2009 baseline assessment and 2012 follow-up of the KORA (Cooperative Health Research in the Region of Augsburg)-Age study from Southern Germany. DA was measured with a Frailty Index (FI). The effects of socio-demographic, socio-economic and lifestyle factors were analyzed using generalized linear mixed models and multinomial regressions. FI scores were available for 1076 participants at baseline (mean age 76years, 50% female) and 808 participants at follow-up. Higher baseline FI levels were significantly associated with higher age, female sex, lower physical activity, moderate alcohol consumption and obesity. Longitudinal increase in FI levels over 3years was 31% (CL: [-3%; 77%]) independent of all examined predictors. The most frequent DA patterns were stability (59%) and gradual decline (30%). Compared to stability, higher age, male sex and low income predicted (mostly fatal) abrupt decline. In conclusion, several factors are associated with FI levels at baseline whereas the change in FI levels over time seems hardly modifiable. Thus, future research should investigate if the same factors predicting older-age FI levels constitute predictors of DA onset earlier in life. Towards the end of life, being male with low income may increase the risk for abrupt decline, indicating need for early detection.

Inverse associations between serum levels of secreted frizzled-related protein-5 (SFRP5) and multiple cardiometabolic risk factors: KORA F4 study

Aims

Secreted frizzled-related protein (Sfrp)5 has beneficial effects on insulin sensitivity, inflammation and cardiovascular risk in different mouse models, but its relevance for cardiometabolic diseases in humans is controversial. We aimed to characterise associations of circulating SFRP5 with cardiometabolic risk factors and prediabetes/type 2 diabetes in a large population-based cohort.

Methods

Cross-sectional associations between serum SFRP5 and cardiometabolic risk factors as well as prediabetes/type 2 diabetes were investigated in 1096 participants aged 62–81 years from the German KORA F4 study, of whom 666 had prediabetes or type 2 diabetes. Multivariable linear regression models were adjusted for potential confounders including age, sex, body mass index (BMI), lifestyle factors, lipids, hypertension, kidney function and myocardial infarction.

Results

Higher serum SFRP5 levels were associated with lower HbA1c, BMI, systolic blood pressure, estimated glomerular filtration rate and high-sensitivity C-reactive protein levels and with higher levels of high-density lipoprotein cholesterol and adiponectin in the fully adjusted model (all P < 0.009). In contrast, favourable associations between SFRP5 and glycaemia, insulin, insulin resistance and other cardiometabolic risk factors were attenuated after adjustment for BMI. Serum SFRP5 levels were lower in participants with prediabetes or type 2 diabetes [(median (25th; 75th percentile) 48.8 (35.5; 65.7) ng/ml] compared to participants with normal glucose tolerance [55.9 (42.6; 69.6) ng/ml] (P < 0.001). In the fully adjusted model, higher SFRP5 was associated with lower odds of prediabetes/type 2 diabetes [OR (95% CI) (0.72 (0.58; 0.89)) per doubling of SFRP5, P < 0.01].

Conclusions

Higher serum SFRP5 was inversely associated with multiple risk factors for type 2 diabetes and cardiovascular diseases. However, BMI represents a strong confounder of some of these associations. Higher circulating SFRP5 was also associated with lower odds of prediabetes/type 2 diabetes, and this association was independent of BMI. Thus, SFRP5 emerges as novel biomarker that merits further research in the context of prevention of cardiometabolic diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0591-x) contains supplementary material, which is available to authorized users.

Lipoprotein(a) and the risk of cardiovascular disease in the European population: results from the BiomarCaRE consortium

AIMS

As promising compounds to lower Lipoprotein(a) (Lp(a)) are emerging, the need for a precise characterization and comparability of the Lp(a)-associated cardiovascular risk is increasing. Therefore, we aimed to evaluate the distribution of Lp(a) concentrations across the European population, to characterize the association with cardiovascular outcomes and to provide high comparability of the Lp(a)-associated cardiovascular risk by use of centrally determined Lp(a) concentrations.

METHODS AND RESULTS

Based on the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE)-project, we analysed data of 56 804 participants from 7 prospective population-based cohorts across Europe with a maximum follow-up of 24 years. All Lp(a) measurements were performed in the central BiomarCaRE laboratory (Biokit Quantia Lp(a)-Test; Abbott Diagnostics). The three endpoints considered were incident major coronary events (MCE), incident cardiovascular disease (CVD) events, and total mortality. We found lower Lp(a) levels in Northern European cohorts (median 4.9 mg/dL) compared to central (median 7.9 mg/dL) and Southern European cohorts (10.9 mg/dL) (Jonckheere-Terpstra test P < 0.001). Kaplan-Meier curves showed the highest event rate of MCE and CVD events for Lp(a) levels ≥90th percentile (log-rank test: P < 0.001 for MCE and CVD). Cox regression models adjusted for age, sex, and cardiovascular risk factors revealed a significant association of Lp(a) levels with MCE and CVD with a hazard ratio (HR) of 1.30 for MCE [95% confidence interval (CI) 1.15‒1.46] and of 1.25 for CVD (95% CI 1.12‒1.39) for Lp(a) levels in the 67‒89th percentile and a HR of 1.49 for MCE (95% CI 1.29‒1.73) and of 1.44 for CVD (95% CI 1.25‒1.65) for Lp(a) levels ≥ 90th percentile vs. Lp(a) levels in the lowest third (P < 0.001 for all). There was no significant association between Lp(a) levels and total mortality. Subgroup analysis for a continuous version of cube root transformed Lp(a) identified the highest Lp(a)-associated risk in individuals with diabetes [HR for MCE 1.31 (95% CI 1.15‒1.50)] and for CVD 1.22 (95% CI 1.08‒1.38) compared to those without diabetes [HR for MCE 1.15 (95% CI 1.08‒1.21; HR for CVD 1.13 (1.07-1.19)] while no difference of the Lp(a)- associated risk were seen for other cardiovascular high risk states. The addition of Lp(a) levels to a prognostic model for MCE and CVD revealed only a marginal but significant C-index discrimination measure increase (0.001 for MCE and CVD; P < 0.05) and net reclassification improvement (0.010 for MCE and 0.011 for CVD).

CONCLUSION

In this large dataset on harmonized Lp(a) determination, we observed regional differences within the European population. Elevated Lp(a) was robustly associated with an increased risk for MCE and CVD in particular among individuals with diabetes. These results may lead to better identification of target populations who might benefit from future Lp(a)-lowering therapies.

Improvement of myocardial infarction risk prediction via inflammation-associated metabolite biomarkers

OBJECTIVE

The comprehensive assaying of low-molecular-weight compounds, for example, metabolomics, provides a unique tool to uncover novel biomarkers and understand pathways underlying myocardial infarction (MI). We used a targeted metabolomics approach to identify biomarkers for MI and evaluate their involvement in the pathogenesis of MI.

METHODS AND RESULTS

Using three independent, prospective cohorts (KORA S4, KORA S2 and AGES-REFINE), totalling 2257 participants without a history of MI at baseline, we identified metabolites associated with incident MI (266 cases). We also investigated the association between the metabolites and high-sensitivity C reactive protein (hsCRP) to understand the relation between these metabolites and systemic inflammation. Out of 140 metabolites, 16 were nominally associated (p<0.05) with incident MI in KORA S4. Three metabolites, arginine and two lysophosphatidylcholines (LPC 17:0 and LPC 18:2), were selected as biomarkers via a backward stepwise selection procedure in the KORA S4 and were significant (p<0.0003) in a meta-analysis comprising all three studies including KORA S2 and AGES-REFINE. Furthermore, these three metabolites increased the predictive value of the Framingham risk score, increasing the area under the receiver operating characteristic score in KORA S4 (from 0.70 to 0.78, p=0.001) and AGES-REFINE study (from 0.70 to 0.76, p=0.02), but was not observed in KORA S2. The metabolite biomarkers attenuated the association between hsCRP and MI, indicating a potential link to systemic inflammatory processes.

CONCLUSIONS

We identified three metabolite biomarkers, which in combination increase the predictive value of the Framingham risk score. The attenuation of the hsCRP-MI association by these three metabolites indicates a potential link to systemic inflammation.

A Low-Frequency Inactivating AKT2 Variant Enriched in the Finnish Population Is Associated With Fasting Insulin Levels and Type 2 Diabetes Risk

To identify novel coding association signals and facilitate characterization of mechanisms influencing glycemic traits and type 2 diabetes risk, we analyzed 109,215 variants derived from exome array genotyping together with an additional 390,225 variants from exome sequence in up to 39,339 normoglycemic individuals from five ancestry groups. We identified a novel association between the coding variant (p.Pro50Thr) in AKT2 and fasting plasma insulin (FI), a gene in which rare fully penetrant mutations are causal for monogenic glycemic disorders. The low-frequency allele is associated with a 12% increase in FI levels. This variant is present at 1.1% frequency in Finns but virtually absent in individuals from other ancestries. Carriers of the FI-increasing allele had increased 2-h insulin values, decreased insulin sensitivity, and increased risk of type 2 diabetes (odds ratio 1.05). In cellular studies, the AKT2-Thr50 protein exhibited a partial loss of function. We extend the allelic spectrum for coding variants in AKT2 associated with disorders of glucose homeostasis and demonstrate bidirectional effects of variants within the pleckstrin homology domain of AKT2.

Sarcopenia is associated with disability status-results from the KORA-Age study

We estimated the prevalence of sarcopenia and its impact on disability in older people. Sarcopenia was found to contribute to higher disability scores. However, our study was not able to show any influence of sarcopenia on the rate of functional decline. This directs attention to an accurate diagnosis of sarcopenia as the onset may be influenced, but its rate may not.

INTRODUCTION

The objectives of this study using data from a population-based cohort were to estimate the prevalence of sarcopenia in older people in Germany and to test the hypothesis that sarcopenia is associated with disability in older adults.

METHODS

Cross-sectional (n = 927) and longitudinal analyses (n = 859) of participants aged ≥65 years at baseline from southern Germany enrolled in the Cooperative Health Research in the Region Augsburg (KORA)-Age study (2009-2012). Sarcopenia was defined based on the European Working Group on Sarcopenia in Older People (EWGSOP) algorithm which includes the presence of both low muscle mass and low muscle function (strength or performance). Disability status was measured by the Health Assessment Questionnaire-Disability Index (HAQ-DI). The presence of disability was defined as HAQ-DI >0. Directed acyclic graphs (DAGs) were constructed to identify potential confounders. The effect of sarcopenia on disability was analyzed using linear mixed effect models with disability values as a continuous outcome.

RESULTS

The overall prevalence of sarcopenia was 5.7% (men 4.0%, women 7.5%) and increased with age. The 3-year incidence of disability was 32.7%. After adjustment for potential confounders, presence of sarcopenia was significantly associated with higher disability scores (0.142 [confidence interval 0.029-0.254]).

CONCLUSION

The prevalence of sarcopenia is consistent with estimates from other European studies using this algorithm. Our results suggest that sarcopenia can contribute to higher disability scores in older adults. However, our study was not able to show any influence of sarcopenia on the rate of functional decline using the EWGSOP diagnostic algorithm for sarcopenia. This directs attention to an accurate diagnosis of sarcopenia as the onset may be influenced, but its rate may not.

Cystatin C and Cardiovascular Disease: A Mendelian Randomization Study

BACKGROUND

Epidemiological studies show that high circulating cystatin C is associated with risk of cardiovascular disease (CVD), independent of creatinine-based renal function measurements. It is unclear whether this relationship is causal, arises from residual confounding, and/or is a consequence of reverse causation.

OBJECTIVES

The aim of this study was to use Mendelian randomization to investigate whether cystatin C is causally related to CVD in the general population.

METHODS

We incorporated participant data from 16 prospective cohorts (n = 76,481) with 37,126 measures of cystatin C and added genetic data from 43 studies (n = 252,216) with 63,292 CVD events. We used the common variant rs911119 in CST3 as an instrumental variable to investigate the causal role of cystatin C in CVD, including coronary heart disease, ischemic stroke, and heart failure.

RESULTS

Cystatin C concentrations were associated with CVD risk after adjusting for age, sex, and traditional risk factors (relative risk: 1.82 per doubling of cystatin C; 95% confidence interval [CI]: 1.56 to 2.13; p = 2.12 × 10⁻¹⁴). The minor allele of rs911119 was associated with decreased serum cystatin C (6.13% per allele; 95% CI: 5.75 to 6.50; p = 5.95 × 10⁻²¹¹), explaining 2.8% of the observed variation in cystatin C. Mendelian randomization analysis did not provide evidence for a causal role of cystatin C, with a causal relative risk for CVD of 1.00 per doubling cystatin C (95% CI: 0.82 to 1.22; p = 0.994), which was statistically different from the observational estimate (p = 1.6 × 10⁻⁵). A causal effect of cystatin C was not detected for any individual component of CVD.

CONCLUSIONS

Mendelian randomization analyses did not support a causal role of cystatin C in the etiology of CVD. As such, therapeutics targeted at lowering circulating cystatin C are unlikely to be effective in preventing CVD.

Circulating Levels of Interleukin 1-Receptor Antagonist and Risk of Cardiovascular Disease

Objective—

Interleukin (IL)-1β represents a key cytokine in the development of cardiovascular disease (CVD). IL-1β is counter-regulated by IL-1 receptor antagonist (IL-1RA), an endogenous inhibitor. This study aimed to identify population-based studies on circulating IL-1RA and incident CVD in a systematic review, estimate the association between IL-1RA and incident CVD in a meta-analysis, and to test whether the association between IL-1RA and incident CVD is explained by other inflammation-related biomarkers in the MONICA/KORA Augsburg case–cohort study (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease/Cooperative Health Research in the Region of Augsburg).

Approach and Results—

We performed a systematic literature search and identified 5 cohort studies on IL-1RA and incident CVD in addition to the MONICA/KORA Augsburg case–cohort study for a meta-analysis based on a total of 1855 CVD cases and 18 745 noncases with follow-up times between 5 and 16 years. The pooled standardized hazard ratio (95% confidence interval) for incident CVD was 1.11 (1.06–1.17) after adjustment for age, sex, anthropometric, metabolic, and lifestyle factors ( P <0.0001). There was no heterogeneity in effect sizes (I 2 =0%; P =0.88). More detailed analyses in the MONICA/KORA study showed that the excess risk for CVD was attenuated by ≥10% after additional separate adjustment for serum levels of high-sensitivity C-reactive protein, IL-6, myeloperoxidase, soluble E-selectin, or soluble intercellular adhesion molecule-1.

Conclusions—

Serum IL-1RA levels were positively associated with risk of CVD after adjustment for multiple confounders in a meta-analysis of 6 population-based cohorts. This association may at least partially reflect a response to triggers inducing subclinical inflammation, oxidative stress, and endothelial activation.

Genome-wide meta-analysis of 241,258 adults accounting for smoking behaviour identifies novel loci for obesity traits

Few genome-wide association studies (GWAS) account for environmental exposures, like smoking, potentially impacting the overall trait variance when investigating the genetic contribution to obesity-related traits. Here, we use GWAS data from 51,080 current smokers and 190,178 nonsmokers (87% European descent) to identify loci influencing BMI and central adiposity, measured as waist circumference and waist-to-hip ratio both adjusted for BMI. We identify 23 novel genetic loci, and 9 loci with convincing evidence of gene-smoking interaction (GxSMK) on obesity-related traits. We show consistent direction of effect for all identified loci and significance for 18 novel and for 5 interaction loci in an independent study sample. These loci highlight novel biological functions, including response to oxidative stress, addictive behaviour, and regulatory functions emphasizing the importance of accounting for environment in genetic analyses. Our results suggest that tobacco smoking may alter the genetic susceptibility to overall adiposity and body fat distribution.

Physical activity, muscular strength, and polypharmacy among older multimorbid persons: Results from the KORA-Age study

The purpose of this study was to examine whether physical activity (PA) and muscular strength (MS) are related to polypharmacy. Our cross-sectional analysis was based on 711 patients with multimorbidity (MMB), aged 65-94 years, who participated in the KORA-Age study. Participants underwent a face-to-face interview and extensive physical examinations including anthropometric measurements, registration of chronic diseases, determination of health-related behaviors (smoking, alcohol intake, physical activity, etc.), collection of blood samples and measurement of hand-grip strength. PPha was defined as the use of >4 drugs and MMB as having ≥2 of 13 chronic diseases. Prevalence of PPha was 44.6% (n=317), and a significant difference was found in the number of drugs used between participants with and without PPha (7.2±2.1 vs 2.5±1.2, P<.001). Patients in the lower compared to the upper tertile of physical activity had a significantly increased odds to be on PPha (OR: 1.64, 95% CI: 1.05-2.56, P=.031) after controlling for age, gender, BMI, family status, education, alcohol intake, smoking habits, number of diseases, hs-CRP, and telomere length. On the contrary, no significant association between muscular strength and PPha was found (OR: 1.04, 95% CI: 0.66-1.63, P=.873) after multivariable adjustment. Among older persons with MMB, lower levels of physical activity, but not low muscular strength, are associated with higher odds of PPha. Increasing the levels of physical activity appears to be highly recommended in order to potentially reduce the risk of PPha among multimorbid persons aged 65 and older.

Proinflammatory Cytokines Predict the Incidence and Progression of Distal Sensorimotor Polyneuropathy: KORA F4/FF4 Study

OBJECTIVE

Experimental and epidemiological studies have implicated inflammatory processes in the pathogenesis of distal sensorimotor polyneuropathy (DSPN), but prospective studies are lacking. We hypothesized that biomarkers of inflammation predict the development and progression of DSPN in a population-based cohort.

RESEARCH DESIGN AND METHODS

This study was based on participants aged 62-81 years from the Cooperative Health Research in the Region of Augsburg (KORA) F4/FF4 cohort, with a mean follow-up of 6.5 years. The predictive value of systemic levels of eight biomarkers of inflammation was assessed for incident DSPN in 133 incident case subjects and 397 individuals without incident DSPN, and for DSPN progression in 57 patients with prevalent DSPN at both time points.

RESULTS

Higher hs-CRP, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1 receptor antagonist (IL-1RA), and soluble intercellular adhesion molecule (sICAM-1) and lower adiponectin levels were associated with incident DSPN in age- and sex-adjusted analysis; IL-18 and omentin were not. IL-6 (odds ratio 1.31 [95% CI 1.00-1.71]) and TNF-α (odds ratio 1.31 [95% CI 1.03-1.67]) remained associated with incident DSPN after adjusting for known DSPN risk factors. The addition of both cytokines to a clinical risk model improved model fit and reclassification. sICAM-1 and IL-1RA were positively associated with progression of DSPN.

CONCLUSIONS

Systemic subclinical and vascular inflammation predicted both the onset and progression of DSPN over 6.5 years in an older general population. Thus modulation of inflammatory processes may be relevant to prevent and/or treat diabetic neuropathy.

Genome-wide physical activity interactions in adiposity - A meta-analysis of 200,452 adults

Physical activity (PA) may modify the genetic effects that give rise to increased risk of obesity. To identify adiposity loci whose effects are modified by PA, we performed genome-wide interaction meta-analyses of BMI and BMI-adjusted waist circumference and waist-hip ratio from up to 200,452 adults of European (n = 180,423) or other ancestry (n = 20,029). We standardized PA by categorizing it into a dichotomous variable where, on average, 23% of participants were categorized as inactive and 77% as physically active. While we replicate the interaction with PA for the strongest known obesity-risk locus in the FTO gene, of which the effect is attenuated by ~30% in physically active individuals compared to inactive individuals, we do not identify additional loci that are sensitive to PA. In additional genome-wide meta-analyses adjusting for PA and interaction with PA, we identify 11 novel adiposity loci, suggesting that accounting for PA or other environmental factors that contribute to variation in adiposity may facilitate gene discovery.

Physical activity levels, duration pattern and adherence to WHO recommendations in German adults

BACKGROUND

Intensity and duration of physical activity are associated with the achievement of health benefits. Our aim was to characterize physical activity behavior in terms of intensity, duration pattern, and adherence to the WHO physical activity recommendations in a population-based sample of adults from southern Germany. Further, we investigated associations between physical activity and sex, age, and body mass index (BMI), considering also common chronic diseases.

METHODS

We analyzed 475 subjects (47% males, mean age 58 years, range 48-68 years) who wore ActiGraph accelerometers for up to seven days. Measured accelerations per minute obtained from the vertical axis (uniaxial) and the vector magnitude of all three axes (triaxial) were classified as sedentary, light or moderate-to-vigorous physical activity (MVPA) according to predefined acceleration count cut-offs. The average minutes/day spent in each activity level per subject served as outcome. Associations of sex, age, BMI, and seven chronic diseases or health limitations, with the activity levels were analyzed by negative binomial regression.

RESULTS

Most of the wear time was spent in sedentarism (median 61%/day), whereas the median time spent in MVPA was only 3%, with men achieving more MVPA than women (35 vs. 28 minutes/day, p<0.05). Almost two thirds of MVPA was achieved in short bouts of less than 5 minutes, and 35% of the subjects did not achieve a single 10-minute bout. Hence, only 14% adhered to the WHO recommendation of 2.5 hours of MVPA/week in at least 10-minute bouts. Females, older subjects and obese subjects spent less time in MVPA (p<0.05), but no clear association with hypertension, asthma, diabetes, chronic obstructive pulmonary disease, anxiety/depression, pain or walking difficulties was observed in regression analyses with MVPA as outcome.

CONCLUSIONS

Activity behavior among middle-aged German adults was highly insufficient, indicating a further need for physical activity promotion in order to gain health benefits.

Relationship between sleep disturbances and multimorbidity among community-dwelling men and women aged 65-93 years: results from the KORA Age Study

BACKGROUND/OBJECTIVE

Although the association of disturbed sleep with specific chronic conditions is well known, the relationship between sleep disturbances and multiple diseases is less clear. Therefore, the objectives of this study were to examine the independent relationships of various sleep disturbances with 1) multimorbidity (≥2 chronic conditions) and 2) commonly co-occurring pairs of chronic conditions.

METHODS

Analyses were based on data from 4127 individuals aged ≥65 years participating in the population-based cross-sectional Cooperative Health Research in the Region of Augsburg (KORA) Age Study conducted from 2008 to 2009 in Germany. Sex-specific odds ratios (OR) and 95% confidence intervals (CI) were calculated from sequential logistic regression models.

RESULTS

Neither short nor long daily sleep duration was significantly associated with multimorbidity among men; a significant positive relationship was identified regarding short sleep duration among women (OR 2.16, 95% CI: 1.42-3.30). While insomnia and all unique symptoms of insomnia were connected to multimorbidity among women in the multivariable models, the relationship concerning trouble falling asleep no longer remained significant after adjustment for all covariables among men. Regarding commonly co-occurring pairs of conditions, the clearest associations were observed between insomnia and daytime tiredness with joint diseases/eye diseases in men and joint diseases/heart diseases in women.

CONCLUSIONS

There seems to be sex-specific particularities in the relationship between sleep disturbances and sleep duration with multimorbidity and commonly co-occurring pairs of chronic conditions in older adults from the general population.

Predicting glycated hemoglobin levels in the non-diabetic general population: Development and validation of the DIRECT-DETECT prediction model - a DIRECT study

Aims/hypothesis

To develop a prediction model that can predict HbA1c levels after six years in the non-diabetic general population, including previously used readily available predictors.

Methods

Data from 5,762 initially non-diabetic subjects from three population-based cohorts (Hoorn Study, Inter99, KORA S4/F4) were combined to predict HbA1c levels at six year follow-up. Using backward selection, age, BMI, waist circumference, use of anti-hypertensive medication, current smoking and parental history of diabetes remained in sex-specific linear regression models. To minimize overfitting of coefficients, we performed internal validation using bootstrapping techniques. Explained variance, discrimination and calibration were assessed using R², classification tables (comparing highest/lowest 50% HbA1c levels) and calibration graphs. The model was externally validated in 2,765 non-diabetic subjects of the population-based cohort METSIM.

Results

At baseline, mean HbA1c level was 5.6% (38 mmol/mol). After a mean follow-up of six years, mean HbA1c level was 5.7% (39 mmol/mol). Calibration graphs showed that predicted HbA1c levels were somewhat underestimated in the Inter99 cohort and overestimated in the Hoorn and KORA cohorts, indicating that the model’s intercept should be adjusted for each cohort to improve predictions. Sensitivity and specificity (95% CI) were 55.7% (53.9, 57.5) and 56.9% (55.1, 58.7) respectively, for women, and 54.6% (52.7, 56.5) and 54.3% (52.4, 56.2) for men. External validation showed similar performance in the METSIM cohort.

Conclusions/interpretation

In the non-diabetic population, our DIRECT-DETECT prediction model, including readily available predictors, has a relatively low explained variance and moderate discriminative performance, but can help to distinguish between future highest and lowest HbA1c levels. Absolute HbA1c values are cohort-dependent.

Serum levels of interleukin-22, cardiometabolic risk factors and incident type 2 diabetes: KORA F4/FF4 study

AIMS

Interleukin-22 (IL-22) has beneficial effects on body weight, insulin resistance and inflammation in different mouse models, but its relevance for the development of type 2 diabetes in humans is unknown. We aimed to identify correlates of serum IL-22 levels and to test the hypothesis that higher IL-22 levels are associated with lower diabetes incidence.

METHODS

Cross-sectional associations between serum IL-22, cardiometabolic risk factors and glucose tolerance status were investigated in 1107 persons of the population-based KORA F4 study. The prospective association between serum IL-22 and incident type 2 diabetes was assessed in 504 initially non-diabetic study participants in both the KORA F4 study and its 7-year follow-up examination KORA FF4, 76 of whom developed diabetes.

RESULTS

Male sex, current smoking, lower HDL cholesterol, lower estimated glomerular filtration rate and higher serum interleukin-1 receptor antagonist were associated with higher IL-22 levels after adjustment for confounders (all P < 0.05). Serum IL-22 showed no associations with glucose tolerance status, prediabetes or type 2 diabetes. Baseline serum IL-22 levels (median, 25th/75th percentiles) for incident type 2 diabetes cases and non-cases were 6.28 (1.95; 12.35) and 6.45 (1.95; 11.80) pg/ml, respectively (age and sex-adjusted P = 0.744). The age and sex-adjusted OR (95% CI) per doubling of IL-22 for incident type 2 diabetes of 1.02 (0.85; 1.23) was almost unchanged after consideration of further confounders.

CONCLUSIONS

High serum levels of IL-22 were positively rather than inversely associated with several cardiometabolic risk factors. However, these associations did not translate into an increased risk for type 2 diabetes. Thus, our data argue against the utility of IL-22 as biomarker for prevalent or incident type 2 diabetes in humans, but identify potential determinants of IL-22 levels which merits further research in the context of cardiovascular diseases.

Epigenome-wide association study of body mass index, and the adverse outcomes of adiposity

Overweight and obesity affect ~1.5 billion people worldwide, and are major risk factors for type-2 diabetes (T2D), cardiovascular disease and related metabolic and inflammatory disturbances.1,2 Although the mechanisms linking adiposity to its clinical sequelae are poorly understood, recent studies suggest that adiposity may influence DNA methylation,3–6 a key regulator of gene expression and molecular phenotype.7 Here we use epigenome-wide association to show that body mass index (BMI, a key measure of adiposity) is associated with widespread changes in DNA methylation (187 genetic loci at P<1x10^-7, range P=9.2x10^-8 to 6.0x10^-46; N=10,261 samples). Genetic association analyses demonstrate that the alterations in DNA methylation are predominantly the consequence of adiposity, rather than the cause. We find the methylation loci are enriched for functional genomic features in multiple tissues (P<0.05), and show that sentinel methylation markers identify gene expression signatures at 38 loci (P<9.0x10^-6, range P=5.5x10^-6 to 6.1x10^-35, N=1,785 samples). The methylation loci identified highlight genes involved in lipid and lipoprotein metabolism, substrate transport, and inflammatory pathways. Finally, we show that the disturbances in DNA methylation predict future type-2 diabetes (relative risk per 1SD increase in Methylation Risk Score: 2.3 [2.07-2.56]; P=1.1x10^-54). Our results provide new insights into the biologic pathways influenced by adiposity, and may enable development of new strategies for prediction and prevention of type-2 diabetes and other adverse clinical consequences of obesity.

Gender differences in the association between grip strength and mortality in older adults: results from the KORA-age study

Background

Reduced muscular strength in the old age is strongly related to activity impairment and mortality. However, studies evaluating the gender-specific association between muscularity and mortality among older adults are lacking. Thus, the objective of the present study was to examine gender differences in the association between muscular strength and mortality in a prospective population-based cohort study.

Methods

Data used in this study derived from the Cooperative Health Research in the Region of Augsburg (KORA)-Age Study. The present analysis includes 1,066 individuals (mean age 76 ± 11 SD years) followed up over 3 years. Handgrip strength was measured using the Jamar Dynamometer. A Cox proportional hazard model was used to determine adjusted hazard ratios of mortality with 95% confidence intervals (95% CI) for handgrip strength. Potential confounders (i.e. age, nutritional status, number of prescribed drugs, diseases and level of physical activity) were pre-selected according to evidence-based information.

Results

During the follow-up period, 56 men (11%) and 39 women (7%) died. Age-adjusted mortality rates per 1,000 person years (95% CI) were 77 (59–106), 24 (13–41) and 14 (7–30) for men and 57 (39–81), 14 (7–27) and 1 (0–19) for women for the first, second and third sex-specific tertile of muscular strength, respectively. Low handgrip strength was significantly associated with all-cause mortality among older men and women from the general population after controlling for significant confounders. Hazard ratios (95% CI) comparing the first and second tertile to the third tertle were 3.33 (1.53–7.22) and 1.42 (0.61-3.28), respectively. Respective hazard ratios (95% CI) for mortality were higher in women than in men ((5.23 (0.67–40.91) and 2.17 (0.27–17.68) versus 2.36 (0.97–5.75) and 0.97 (0.36–2.57)).

Conclusions

Grip strength is inversely associated with mortality risk in older adults, and this association is independent of age, nutritional status, number of prescribed drugs, number of chronic diseases and level of physical activity. The association between muscular strength and all-cause mortality tended to be stronger in women. It seems to be particularly important for the weakest to enhance their levels of muscular strength in order to reduce the risk of dying early.

Cost burden of type 2 diabetes in Germany: results from the population-based KORA studies

OBJECTIVE

To examine the impact of type 2 diabetes on direct and indirect costs and to describe the effect of relevant diabetes-related factors, such as type of treatment or glycaemic control on direct costs.

DESIGN

Bottom-up excess cost analysis from a societal perspective based on population-based survey data.

PARTICIPANTS

9160 observations from 6803 individuals aged 31-96 years (9.6% with type 2 diabetes) from the population-based KORA (Cooperative Health Research in the Region of Augsburg) studies in Southern Germany.

OUTCOME MEASURES

Healthcare usage, productivity losses, and resulting direct and indirect costs.

METHODS

Information on diabetes status, biomedical/sociodemographic variables, medical history and on healthcare usage and productivity losses was assessed in standardised interviews and examinations. Healthcare usage and productivity losses were costed with reference to unit prices and excess costs of type 2 diabetes were calculated using generalised linear models.

RESULTS

Individuals with type 2 diabetes had 1.81 (95% CI 1.56 to 2.11) times higher direct (€3352 vs €1849) and 2.07 (1.51 to 2.84) times higher indirect (€4103 vs €1981) annual costs than those without diabetes. Cardiovascular complications, a long diabetes duration and treatment with insulin were significantly associated with increased direct costs; however, glycaemic control was only weakly insignificantly associated with costs.

CONCLUSIONS

This study illustrates the substantial direct and indirect societal cost burden of type 2 diabetes in Germany. Strong effort is needed to optimise care to avoid progression of the disease and costly complications.

Epigenetic Signatures at AQP3 and SOCS3 Engage in Low-Grade Inflammation across Different Tissues

BACKGROUND

Elevated levels of C-reactive protein (CRP, determined by a high-sensitivity assay) indicate low-grade inflammation which is implicated in many age-related disorders. Epigenetic studies on CRP might discover molecular mechanisms underlying CRP regulation. We aimed to identify DNA methylation sites related to CRP concentrations in cells and tissues regulating low-grade inflammation.

RESULTS

Genome-wide DNA methylation was measured in peripheral blood in 1,741 participants of the KORA F4 study using Illumina HumanMethylation450 BeadChip arrays. Four CpG sites (located at BCL3, AQP3, SOCS3, and cg19821297 intergenic at chromosome 19p13.2, P ≤ 1.01E-07) were significantly hypomethylated at high CRP concentrations independent of various confounders including age, sex, BMI, smoking, and white blood cell composition. Findings were not sex-specific. CRP-related top genes were enriched in JAK/STAT pathways (Benjamini-Hochberg corrected P < 0.05). Results were followed-up in three studies using DNA from peripheral blood (EPICOR, n = 503) and adipose tissue (TwinsUK, n = 368) measured as described above and from liver tissue (LMU liver cohort, n = 286) measured by MALDI-TOF mass spectrometry using EpiTYPER. CpG sites at the AQP3 locus (significant p-values in peripheral blood = 1.72E-03 and liver tissue = 1.51E-03) and the SOCS3 locus (p-values in liver < 2.82E-05) were associated with CRP in the validation panels.

CONCLUSIONS

Epigenetic modifications seem to engage in low-grade inflammation, possibly via JAK/STAT mediated pathways. Results suggest a shared relevance across different tissues at the AQP3 locus and highlight a role of DNA methylation for CRP regulation at the SOCS3 locus.

Assessment of predictive performance in incomplete data by combining internal validation and multiple imputation

BACKGROUND

Missing values are a frequent issue in human studies. In many situations, multiple imputation (MI) is an appropriate missing data handling strategy, whereby missing values are imputed multiple times, the analysis is performed in every imputed data set, and the obtained estimates are pooled. If the aim is to estimate (added) predictive performance measures, such as (change in) the area under the receiver-operating characteristic curve (AUC), internal validation strategies become desirable in order to correct for optimism. It is not fully understood how internal validation should be combined with multiple imputation.

METHODS

In a comprehensive simulation study and in a real data set based on blood markers as predictors for mortality, we compare three combination strategies: Val-MI, internal validation followed by MI on the training and test parts separately, MI-Val, MI on the full data set followed by internal validation, and MI(-y)-Val, MI on the full data set omitting the outcome followed by internal validation. Different validation strategies, including bootstrap und cross-validation, different (added) performance measures, and various data characteristics are considered, and the strategies are evaluated with regard to bias and mean squared error of the obtained performance estimates. In addition, we elaborate on the number of resamples and imputations to be used, and adopt a strategy for confidence interval construction to incomplete data.

RESULTS

Internal validation is essential in order to avoid optimism, with the bootstrap 0.632+ estimate representing a reliable method to correct for optimism. While estimates obtained by MI-Val are optimistically biased, those obtained by MI(-y)-Val tend to be pessimistic in the presence of a true underlying effect. Val-MI provides largely unbiased estimates, with a slight pessimistic bias with increasing true effect size, number of covariates and decreasing sample size. In Val-MI, accuracy of the estimate is more strongly improved by increasing the number of bootstrap draws rather than the number of imputations. With a simple integrated approach, valid confidence intervals for performance estimates can be obtained.

CONCLUSIONS

When prognostic models are developed on incomplete data, Val-MI represents a valid strategy to obtain estimates of predictive performance measures.

Recalibration of the ACC/AHA Risk Score in Two Population-Based German Cohorts

Background

The 2013 ACC/AHA guidelines introduced an algorithm for risk assessment of atherosclerotic cardiovascular disease (ASCVD) within 10 years. In Germany, risk assessment with the ESC SCORE is limited to cardiovascular mortality. Applicability of the novel ACC/AHA risk score to the German population has not yet been assessed. We therefore sought to recalibrate and evaluate the ACC/AHA risk score in two German cohorts and to compare it to the ESC SCORE.

Methods

We studied 5,238 participants from the KORA surveys S3 (1994–1995) and S4 (1999–2001) and 4,208 subjects from the Heinz Nixdorf Recall (HNR) Study (2000–2003). There were 383 (7.3%) and 271 (6.4%) first non-fatal or fatal ASCVD events within 10 years in KORA and in HNR, respectively. Risk scores were evaluated in terms of calibration and discrimination performance.

Results

The original ACC/AHA risk score overestimated 10-year ASCVD rates by 37% in KORA and 66% in HNR. After recalibration, miscalibration diminished to 8% underestimation in KORA and 12% overestimation in HNR. Discrimination performance of the ACC/AHA risk score was not affected by the recalibration (KORA: C = 0.78, HNR: C = 0.74). The ESC SCORE overestimated by 5% in KORA and by 85% in HNR. The corresponding C-statistic was 0.82 in KORA and 0.76 in HNR.

Conclusions

The recalibrated ACC/AHA risk score showed strongly improved calibration compared to the original ACC/AHA risk score. Predicting only cardiovascular mortality, discrimination performance of the commonly used ESC SCORE remained somewhat superior to the ACC/AHA risk score. Nevertheless, the recalibrated ACC/AHA risk score may provide a meaningful tool for estimating 10-year risk of fatal and non-fatal cardiovascular disease in Germany.

Characterization of the metabolic profile associated with serum 25-hydroxyvitamin D: a cross-sectional analysis in population-based data

BACKGROUND

Numerous observational studies have observed associations between vitamin D deficiency and cardiometabolic diseases, but these findings might be confounded by obesity. A characterization of the metabolic profile associated with serum 25-hydroxyvitamin D [25(OH)D] levels, in general and stratified by abdominal obesity, may help to untangle the relationship between vitamin D, obesity and cardiometabolic health.

METHODS

Serum metabolomics measurements were obtained from a nuclear magnetic resonance spectroscopy (NMR)- and a mass spectrometry (MS)-based platform. The discovery was conducted in 1726 participants of the population-based KORA-F4 study, in which the associations of the concentrations of 415 metabolites with 25(OH)D levels were assessed in linear models. The results were replicated in 6759 participants (NMR) and 609 (MS) participants, respectively, of the population-based FINRISK 1997 study.

RESULTS

Mean [standard deviation (SD)] 25(OH)D levels were 15.2 (7.5) ng/ml in KORA F4 and 13.8 (5.9) ng/ml in FINRISK 1997; 37 metabolites were associated with 25(OH)D in KORA F4 at P < 0.05/415. Of these, 30 associations were replicated in FINRISK 1997 at P < 0.05/37. Among these were constituents of (very) large very-low-density lipoprotein and small low-density lipoprotein subclasses and related measures like serum triglycerides as well as fatty acids and measures reflecting the degree of fatty acid saturation. The observed associations were independent of waist circumference and generally similar in abdominally obese and non-obese participants.

CONCLUSIONS

Independently of abdominal obesity, higher 25(OH)D levels were associated with a metabolite profile characterized by lower concentrations of atherogenic lipids and a higher degree of fatty acid polyunsaturation. These results indicate that the relationship between vitamin D deficiency and cardiometabolic diseases is unlikely to merely reflect obesity-related pathomechanisms.

MASP1, THBS1, GPLD1 and ApoA-IV are novel biomarkers associated with prediabetes: the KORA F4 study

AIMS/HYPOTHESIS

Individuals at a high risk of type 2 diabetes demonstrate moderate impairments in glucose metabolism years before the clinical manifestation of type 2 diabetes, a state called 'prediabetes'. In order to elucidate the pathophysiological processes leading to type 2 diabetes, we aimed to identify protein biomarkers associated with prediabetes.

METHODS

In a proteomics study, we used targeted selected reaction monitoring (SRM)-MS to quantify 23 candidate proteins in the plasma of 439 randomly selected men and women aged 47-76 years from the population-based German KORA F4 study. Cross-sectional associations of protein levels with prediabetes (impaired fasting glucose and/or impaired glucose tolerance), type 2 diabetes, glucose levels in both the fasting state and 2 h after an OGTT, fasting insulin and insulin resistance were investigated using regression models adjusted for technical covariables, age, sex, BMI, smoking, alcohol intake, physical inactivity, actual hypertension, triacylglycerol levels, total cholesterol/HDL-cholesterol ratio, and high-sensitivity C-reactive protein levels.

RESULTS

Mannan-binding lectin serine peptidase 1 (MASP1; OR per SD 1.77 [95% CI 1.26, 2.47]), thrombospondin 1 (THBS1; OR per SD 1.55 [95% CI 1.16, 2.07]) and glycosylphosphatidylinositol-specific phospholipase D1 (GPLD1; OR per SD 1.40 [95% CI 1.01, 1.94]) were positively associated with prediabetes, and apolipoprotein A-IV (ApoA-IV; OR per SD 0.75 [95% CI 0.56, 1.00]) was inversely associated with prediabetes. MASP1 was positively associated with fasting and 2 h glucose levels. ApoA-IV was inversely and THBS1 was positively associated with 2 h glucose levels. MASP1 associations with prediabetes and fasting glucose resisted Bonferroni correction. Type 2 diabetes associations were partly influenced by glucose-lowering medication.

CONCLUSIONS/INTERPRETATION

We discovered novel and independent associations of prediabetes and related traits with MASP1, and some evidence for associations with THBS1, GPLD1 and ApoA-IV, suggesting a role for these proteins in the pathophysiology of type 2 diabetes.

What is the impact of different spirometric criteria on the prevalence of spirometrically defined COPD and its comorbidities? Results from the population-based KORA study

Background

There is an ongoing debate about the appropriate spirometric criterion for airway obstruction to detect COPD. Furthermore, the association of different criteria with comorbidity prevalence and inflammatory biomarkers in advanced age is unclear.

Materials and methods

Spirometry was performed in a population-based study (n=2,256) covering an age range of 41–90 years. COPD was spirometrically determined either by a fixed ratio (FR) of <0.7 for forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) or by FEV₁/FVC below the lower limit of normal (LLN). Comorbidity prevalences and circulating biomarker levels (C-reactive protein [CRP], interleukin [IL]-6) were compared between subjects with or without COPD by the two criteria using logistic and multiple regression models, adjusting for sex and age.

Results

The prevalence of spirometrically defined COPD by FR increased with age from 10% in subjects aged <65 years to 26% in subjects aged ≥75 years. For LLN-defined COPD, it remained below 10% for all age groups. Overall, COPD diagnosis was not associated with specific comorbidities, except for a lower prevalence of obesity in both FR- and LLN-defined cases. Both CRP and IL-6 tended to be higher in cases by both criteria.

Conclusion

In a population-based cohort of adults up to the age of 90 years, the prevalence of spirometrically defined COPD was higher for the FR criterion than for the LLN criterion. This difference increased with age. Neither prevalences of common comorbidities nor levels of the biomarkers, CRP or IL-6, were conclusively associated with the selection of the COPD criterion. Results have to be considered in light of the predominantly mild cases of airway obstruction in the examined study population.

Metabolites of milk intake: a metabolomic approach in UK twins with findings replicated in two European cohorts

Purpose

Milk provides a significant source of calcium, protein, vitamins and other minerals to Western populations throughout life. Due to its widespread use, the metabolic and health impact of milk consumption warrants further investigation and biomarkers would aid epidemiological studies.

Methods

Milk intake assessed by a validated food frequency questionnaire was analyzed against fasting blood metabolomic profiles from two metabolomic platforms in females from the TwinsUK cohort (n = 3559). The top metabolites were then replicated in two independent populations (EGCUT, n = 1109 and KORA, n = 1593), and the results from all cohorts were meta-analyzed.

Results

Four metabolites were significantly associated with milk intake in the TwinsUK cohort after adjustment for multiple testing (P < 8.08 × 10⁻⁵) and covariates (BMI, age, batch effects, family relatedness and dietary covariates) and replicated in the independent cohorts. Among the metabolites identified, the carnitine metabolite trimethyl-N-aminovalerate (β = 0.012, SE = 0.002, P = 2.98 × 10⁻¹²) and the nucleotide uridine (β = 0.004, SE = 0.001, P = 9.86 × 10⁻⁶) were the strongest novel predictive biomarkers from the non-targeted platform. Notably, the association between trimethyl-N-aminovalerate and milk intake was significant in a group of MZ twins discordant for milk intake (β = 0.050, SE = 0.015, P = 7.53 × 10⁻⁴) and validated in the urine of 236 UK twins (β = 0.091, SE = 0.032, P = 0.004). Two metabolites from the targeted platform, hydroxysphingomyelin C14:1 (β = 0.034, SE = 0.005, P = 9.75 × 10⁻¹⁴) and diacylphosphatidylcholine C28:1 (β = 0.034, SE = 0.004, P = 4.53 × 10⁻¹⁶), were also replicated.

Conclusions

We identified and replicated in independent populations four novel biomarkers of milk intake: trimethyl-N-aminovalerate, uridine, hydroxysphingomyelin C14:1 and diacylphosphatidylcholine C28:1. Together, these metabolites have potential to objectively examine and refine milk-disease associations.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-016-1278-x) contains supplementary material, which is available to authorized users.

Correction: The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study

[This corrects the article DOI: 10.1371/journal.pgen.1005378.].

Specific Metabolic Markers Are Associated with Future Waist-Gaining Phenotype in Women

OBJECTIVE

Our study aims to identify metabolic markers associated with either a gain in abdominal (measured by waist circumference) or peripheral (measured by hip circumference) body fat mass.

METHODS

Data of 4 126 weight-gaining adults (18-75 years) from three population-based, prospective German cohort studies (EPIC, KORA, DEGS) were analysed regarding a waist-gaining (WG) or hip-gaining phenotype (HG). The phenotypes were obtained by calculating the differences of annual changes in waist minus hip circumference. The difference was displayed for all cohorts. The highest 10% of this difference were defined as WG whereas the lowest 10% were defined as HG. A total of 121 concordant metabolite measurements were conducted using Biocrates AbsoluteIDQ® kits in EPIC and KORA. Sex-specific associations with metabolite concentration as independent and phenotype as the dependent variable adjusted for confounders were calculated. The Benjamini-Hochberg method was used to correct for multiple testing.

RESULTS

Across studies both sexes gained on average more waist than hip circumference. We could identify 12 metabolites as being associated with the WG (n = 8) or HG (n = 4) in men, but none were significant after correction for multiple testing; 45 metabolites were associated with the WG (n = 41) or HG (n = 4) in women. For WG, n = 21 metabolites remained significant after correction for multiple testing. Respective odds ratios (OR) ranged from 0.66 to 0.73 for tryptophan, the diacyl-phosphatidylcholines (PC) C32:3, C36:0, C38:0, C38:1, C42:2, C42:5, the acyl-alkyl-PCs C32:2, C34:0, C36:0, C36:1, C36:2, C38:0, C38:2, C40:1, C40:2, C40:5, C40:6, 42:2, C42:3 and lyso-PC C17:0.

CONCLUSION

Both weight-gaining men and women showed a clear tendency to gain more abdominal than peripheral fat. Gain of abdominal fat seems to be related to an initial metabolic state reflected by low concentrations of specific metabolites, at least in women. Thus, higher levels of specific PCs may play a protective role in gaining waist circumference.

Handgrip strength is inversely and independently associated with multimorbidity among older women: Results from the KORA-Age study

BACKGROUND

Data on the association between handgrip strength and multimorbidity (MMB) are missing.

AIM

The purpose of this study was to examine if handgrip strength is related to MMB in a large population-based sample of older persons.

METHODS

The cross-sectional analysis was based on 1079 older people (aged 65-94years), who participated in the KORA-Age study in the Augsburg region, southern Germany. Participants underwent an interview and extensive examinations, including anthropometric measurements, registration of chronic diseases, determination of health-related behaviors (smoking, alcohol intake and physical activity), collection of blood samples, and muscle strength measurement using hand-grip dynamometry.

RESULTS

In men, handgrip strength correlated strongly with the number of co-existing diseases (r=-0.176, p<0.001), and the same pattern was observed for women (r=-0.287, p<0.001). Among women, handgrip strength in the lower tertile compared to the upper tertile was significantly associated with an increased odds of having MMB (OR: 2.57, 95% CI: 1.30-5.07, p=0.007) after controlling for age, BMI, education, alcohol intake, smoking habits, medications number, inflammatory markers, telomere length and levels of physical activity. Contrary, no significant association between handgrip strength and MMB was found among men (OR: 1.32, 95% CI: 0.73-2.40, p=0.362) after multivariable adjustment.

CONCLUSION

Lower levels of handgrip strength are associated with a higher odd of MMB among older women even after adjusting for traditional and novel confounders. Increasing the levels of muscular strength in older women seems to be important in order to reduce the risk for the co-occurrence of multiple chronic diseases.

Troponin I and cardiovascular risk prediction in the general population: the BiomarCaRE consortium

Aims

Our aims were to evaluate the distribution of troponin I concentrations in population cohorts across Europe, to characterize the association with cardiovascular outcomes, to determine the predictive value beyond the variables used in the ESC SCORE, to test a potentially clinically relevant cut-off value, and to evaluate the improved eligibility for statin therapy based on elevated troponin I concentrations retrospectively.

Methods and results

Based on the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE) project, we analysed individual level data from 10 prospective population-based studies including 74 738 participants. We investigated the value of adding troponin I levels to conventional risk factors for prediction of cardiovascular disease by calculating measures of discrimination (C-index) and net reclassification improvement (NRI). We further tested the clinical implication of statin therapy based on troponin concentration in 12 956 individuals free of cardiovascular disease in the JUPITER study. Troponin I remained an independent predictor with a hazard ratio of 1.37 for cardiovascular mortality, 1.23 for cardiovascular disease, and 1.24 for total mortality. The addition of troponin I information to a prognostic model for cardiovascular death constructed of ESC SCORE variables increased the C-index discrimination measure by 0.007 and yielded an NRI of 0.048, whereas the addition to prognostic models for cardiovascular disease and total mortality led to lesser C-index discrimination and NRI increment. In individuals above 6 ng/L of troponin I, a concentration near the upper quintile in BiomarCaRE (5.9 ng/L) and JUPITER (5.8 ng/L), rosuvastatin therapy resulted in higher absolute risk reduction compared with individuals <6 ng/L of troponin I, whereas the relative risk reduction was similar.

Conclusion

In individuals free of cardiovascular disease, the addition of troponin I to variables of established risk score improves prediction of cardiovascular death and cardiovascular disease.

A high level of household physical activity compensates for lack of leisure time physical activity with regard to deficit accumulation: Results from the KORA-Age study

INTRODUCTION

Aging is associated with increasing loss of physiological resilience and successive accumulation of physiological deficits. This can be measured through a frailty index which sums up symptoms, health conditions and impairments. One possible factor in preventing or delaying deficit accumulation is physical activity. The effect of leisure time physical activity on health is well investigated; however, the effect of household physical activity is less clear. The objective of this cross-sectional study was to examine the association of household physical activity with deficit accumulation while controlling for level of leisure time physical activity.

METHODS

Data originates from the 2008 baseline assessment of the KORA (Cooperative Health Research in the Region of Augsburg)-Age study from Southern Germany. A frailty index of deficit accumulation (Deficit Accumulation Index, DAI) was constructed from 31 age-related health deficits. Physical activity was measured with the Physical Activity Scale for the Elderly (PASE). The association of deficit accumulation and physical activity was analyzed using negative binomial regression analysis.

RESULTS

The participants' (n=960, mean age 76years, 49.0% female) DAI ranged from 0.00 to 0.68. Higher levels of both types of physical activity were statistically significantly associated with less deficit accumulation. Participants in the highest household (leisure time) physical activity quartile had 29% (30%) less deficits than participants in the respective lowest quartiles.

CONCLUSION

High levels of household physical activity might compensate for low levels of leisure time physical activity in the prevention of deficit accumulation. Further research efforts investigating the temporal sequence of this association are needed.

The Pharmacogenetic Footprint of ACE Inhibition: A Population-Based Metabolomics Study

Angiotensin-I-converting enzyme (ACE) inhibitors are an important class of antihypertensives whose action on the human organism is still not fully understood. Although it is known that ACE especially cleaves COOH-terminal dipeptides from active polypeptides, the whole range of substrates and products is still unknown. When analyzing the action of ACE inhibitors, effects of genetic variation on metabolism need to be considered since genetic variance in the ACE gene locus was found to be associated with ACE-concentration in blood as well as with changes in the metabolic profiles of a general population. To investigate the interactions between genetic variance at the ACE-locus and the influence of ACE-therapy on the metabolic status we analyzed 517 metabolites in 1,361 participants from the KORA F4 study. We replicated our results in 1,964 individuals from TwinsUK. We observed differences in the concentration of five dipeptides and three ratios of di- and oligopeptides between ACE inhibitor users and non-users that were genotype dependent. Such changes in the concentration affected major homozygotes, and to a lesser extent heterozygotes, while minor homozygotes showed no or only small changes in the metabolite status. Two of these resulting dipeptides, namely aspartylphenylalanine and phenylalanylserine, showed significant associations with blood pressure which qualifies them—and perhaps also the other dipeptides—as readouts of ACE-activity. Since so far ACE activity measurement is substrate specific due to the usage of only one oligopeptide, taking several dipeptides as potential products of ACE into account may provide a broader picture of the ACE activity.

Socioeconomic status and anthropometric changes-A meta-analytic approach from seven German cohorts

OBJECTIVE

To study the association between socioeconomic status (SES) and annual relative change in anthropometric markers in the general German adult population.

METHODS

Longitudinal data of 56,556 participants aged 18-83 years from seven population-based German cohort studies (CARLA, SHIP, KORA, DEGS, EPIC-Heidelberg, EPIC-Potsdam, PopGen) were analyzed by meta-analysis using a random-effects model. The indicators of SES were education and household income.

RESULTS

On average, all participants gained weight and increased their waist circumference over the study's follow-up period. Men and women in the low education group had a 0.1 percentage points greater annual increase in weight (95% CI men: 0.06-0.20; and women: 0.06-0.12) and waist circumference (95% CI men: 0.01-0.45; and women: 0.05-0.22) than participants in the high education group. Women with low income had a 0.1 percentage points higher annual increase in weight (95% CI 0.00-0.15) and waist circumference (95% CI 0.00-0.14) than women with high income. No association was found for men between income and obesity markers.

CONCLUSIONS

Participants with lower SES (education and for women also income) gained more weight and waist circumference than those with higher SES. These results underline the necessity to evaluate the risk of weight gain based on SES to develop more effective preventive measures.

HbA1c levels in non-diabetic older adults - No J-shaped associations with primary cardiovascular events, cardiovascular and all-cause mortality after adjustment for confounders in a meta-analysis of individual participant data from six cohort studies

BACKGROUND

To determine the shape of the associations of HbA1c with mortality and cardiovascular outcomes in non-diabetic individuals and explore potential explanations.

METHODS

The associations of HbA1c with all-cause mortality, cardiovascular mortality and primary cardiovascular events (myocardial infarction or stroke) were assessed in non-diabetic subjects ≥50 years from six population-based cohort studies from Europe and the USA and meta-analyzed. Very low, low, intermediate and increased HbA1c were defined as <5.0, 5.0 to <5.5, 5.5 to <6.0 and 6.0 to <6.5% (equals <31, 31 to <37, 37 to <42 and 42 to <48 mmol/mol), respectively, and low HbA1c was used as reference in Cox proportional hazards models.

RESULTS

Overall, 6,769 of 28,681 study participants died during a mean follow-up of 10.7 years, of whom 2,648 died of cardiovascular disease. Furthermore, 2,493 experienced a primary cardiovascular event. A linear association with primary cardiovascular events was observed. Adjustment for cardiovascular risk factors explained about 50% of the excess risk and attenuated hazard ratios (95 confidence interval) for increased HbA1c to 1.14 (1.03-1.27), 1.17 (1.00-1.37) and 1.19 (1.04-1.37) for all-cause mortality, cardiovascular mortality and cardiovascular events, respectively. The six cohorts yielded inconsistent results for the association of very low HbA1c levels with the mortality outcomes and the pooled effect estimates were not statistically significant. In one cohort with a pronounced J-shaped association of HbA1c levels with all-cause and cardiovascular mortality (NHANES), the following confounders of the association of very low HbA1c levels with mortality outcomes were identified: race/ethnicity; alcohol consumption; BMI; as well as biomarkers of iron deficiency anemia and liver function. Associations for very low HbA1c levels lost statistical significance in this cohort after adjusting for these confounders.

CONCLUSIONS

A linear association of HbA1c levels with primary cardiovascular events was observed. For cardiovascular and all-cause mortality, the observed small effect sizes at both the lower and upper end of HbA1c distribution do not support the notion of a J-shaped association of HbA1c levels because a certain degree of residual confounding needs to be considered in the interpretation of the results.

Changes in Waist Circumference among German Adults over Time - Compiling Results of Seven Prospective Cohort Studies

AIM

This study aims to quantify longitudinal changes in waist circumference (WC) among adults aged 45-64 years in Germany.

METHODS

Data of 15,444 men and 17,207 women from one nationwide and six regional prospective German cohort studies were analyzed. The sex-specific mean change in WC per year of follow-up was assessed for each study separately. Findings from the cohort-by-cohort analysis were combined by applying meta-analytic methods. Progression to central obesity (WC ≥ 102 cm in men and ≥ 88 cm in women) within a standardized period of 10 years was described for each study.

RESULTS

The estimated mean change in WC per year of follow-up for all cohorts combined was 0.53 (95% confidence interval 0.29-0.76) cm/year for men and 0.63 (0.48-0.77) cm/year for women, but varied between the included studies. Within 10 years, about 20% of individuals with low WC (<94 cm in men; <80 cm in women) and about 50% of individuals with intermediate WC (94-102 cm in men; 80-88 cm in women) progressed to central obesity.

CONCLUSION

The increase in mean WC with aging along with a profound increase of central adiposity is obviously and may have several adverse health effects. Obesity prevention programs should also focus on abdominal obesity.

[Frailty in Germany: status and perspectives : Results from a workshop of the German Society for Epidemiology]

BACKGROUND

A standardized, valid and comparable operationalization and assessment of frailty in population-based studies is essential in order to describe the prevalence and determinants of frailty in the population.

AIM

After an introduction to the subject the main goal of a workshop at the 9th annual meeting of the German Society for Epidemiology (DGEpi) was to present approaches and results from four different studies in Germany.

MATERIAL AND METHODS

The following four population-based studies were used to describe frailty in Germany: the German health interview and examination survey for adults (DEGS1), the epidemiological study on the chances of prevention, early recognition and optimized treatment of chronic diseases in the older population (ESTHER), the cooperative health research in the region Augsburg (KORA Age) study and the longitudinal urban cohort ageing study (LUCAS) in Hamburg.

RESULTS

The four studies consistently showed that frailty is widespread in older and oldest-old persons in Germany. It is obvious that frailty represents a relevant concept in Germany even if there is currently no uniform basis for operationalization.

CONCLUSION

Concepts and instruments for the collation of frailty should be included in future population-based studies in order to make a better assessment of older people's health situation and to describe the unused potential for prevention in an aging society.