Association of the habitual dietary intake with the fatty liver index and effect modification by metabotypes in the population-based KORA-Fit study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging threat for public health with diet being a major risk factor in disease development and progression. However, the effects of habitual food consumption on fatty liver are still inconclusive as well as the proposed role of the individuals' metabolic profiles. Therefore, the aim of our study is to examine the associations between diet and NAFLD with an emphasis on the influence of specific metabotypes in the general population.

METHODS

A total of 689 participants (304 men and 385 women) of the KORA-Fit (S4) survey, a follow-up study of the population-based KORA cohort study running in the Region of Augsburg, Germany, were included in this analysis. Dietary information was derived from repeated 24-h food lists and a food frequency questionnaire. The intake of energy and energy-providing nutrients were calculated using the national food composition database. The presence of fatty liver was quantified by the fatty liver index (FLI), and metabotypes were calculated using K-means clustering. Multivariable linear regression models were used for the analysis of habitual food groups and FLI; for the evaluation of macronutrients, energy substitution models were applied.

RESULTS

A higher consumption of nuts and whole grains, and a better diet quality (according to Alternate Healthy Eating Index and Mediterranean Diet Score) were associated with lower FLI values, while the intake of soft drinks, meat, fish and eggs were associated with a higher FLI. The isocaloric substitution of carbohydrates with polyunsaturated fatty acids was associated with a decreased FLI, while substitution with monounsaturated fatty acids and protein showed increased FLI. Statistically significant interactions with the metabotype were observed for most food groups.

CONCLUSION

The consumption of plant-based food groups, including nuts and whole grains, and diet quality, were associated with lower FLI values, whereas the intake of soft drinks and products of animal origin (meat, fish, eggs) were associated with a higher FLI. The observed statistically significant interactions with the metabotype for most food groups could help to develop targeted prevention strategies on a population-based level if confirmed in independent prospective studies.

Anterior-wall and non-anterior-wall STEMIs do not differ in long-term mortality: results from the augsburg myocardial infarction registry

Background

Different ST-segment elevation myocardial infarction (STEMI) localizations go along with dissimilarities in the size of the affected myocardium, the causing coronary vessel occlusion, and the right ventricular participation. Therefore, this study aims to clarify if there is any difference in long-term survival between anterior- and non-anterior-wall STEMI.

Methods

This study included 2,195 incident STEMI cases that occurred between 2009 and 2017, recorded by the population-based Augsburg Myocardial Infarction Registry, Germany. The study population comprised 1.570 men and 625 women aged 25-84 years at acute myocardial infarction. The patients were observed from the day of their first acute event with an average follow-up period of 4.3 years, (standard deviation: 3.0). Survival analyses and multivariable Cox regression analyses were performed to examine the association between infarction localizations and long-term all-cause mortality.

Results

Of the 2,195 patients, 1,118 had an anterior (AWS)- and 1,077 a non-anterior-wall-STEMI (NAWS). No significant associations of the STEMI localization with long-term mortality were found. When comparing AWS with NAWS, a hazard ratio of 0.91 [95% confidence interval: 0.75-1.10] could be calculated after multivariable adjustment. In contrast to NAWS, AWS was associated with a greater <28 day mortality, less current or former smoking and higher creatine kinase-myocardial band levels (CK-MB) and went along with a higher frequency of impaired left ventricular ejection fraction (<30%).

Conclusions

Despite pathophysiological differences between AWS and NAWS, and identified differences in multiple clinical characteristics, no significant differences in long-term mortality between both groups were observed.

Associations between anthropometric parameters and immune-phenotypical characteristics of circulating Tregs and serum cytokines

OBJECTIVE

To investigate the associations between several anthropometric parameters and regulatory T cells (Tregs) and circulating cytokines in a population-based cohort.

METHODS

Between 2018 and 2021, a total of 238 participants were examined up to three times within the scope of the MEGA study in Augsburg, Germany. Tregs were analyzed using flow cytometry and the serum concentrations of 52 cytokines were determined. Anthropometric parameters were measured, using also bioelectrical impedance analysis: body mass index (BMI), relative total body fat, relative visceral adipose tissue (rVAT), waist circumference (WC), waist-to-hip ratio (WHR) and body fat distribution. Associations were analyzed using linear mixed models with random intercept (Tregs) and conventional linear regression models (cytokines).

RESULTS

WC and WHR were inversely associated with the general Treg subset. Four parameters (BMI, rVAT, WC, and WHR) were inversely associated with the conventional Treg population. Three cytokines showed a particularly strong association with several anthropometric parameters: the cutaneous T-cell attracting chemokine was inversely associated with anthropometric parameters, while hepatocyte growth factor and interleukine-18 showed positive associations.

CONCLUSIONS

Anthropometric measures are associated with Tregs and serum cytokine concentrations revealing new important interconnections between obesity and the adaptive immune system.

COVID-19 risk perceptions, worries and preventive behaviors in patients with previous myocardial infarction: results from the myocardial infarction registry Augsburg

Despite the known association of chronic cardiovascular diseases and more severe courses of COVID-19, little is known about individual risk perception of patients with a history of acute myocardial infarction (AMI) and resulting preventive behaviours. In May 2020, a postal survey was conducted, including 150 patients with previous AMI from the myocardial infarction registry Augsburg. The study objective was to assess COVID-19 knowledge, individual risk perception, worries, infection likelihood and preventive behaviours in this patient cohort. From the 100 respondents, 69.7% perceived themselves to be at high risk of developing a severe course of COVID-19. There was a significant positive correlation between dangerousness assessment and knowledge on COVID-19. Despite a majority (70%) of patients rating their susceptibility for an infection as moderate to very high, the individual likelihood of being infected was rated at only 3%. Almost 70% of patients with previous MI classified themselves at high risk for a severe course of COVID-19 infection. As seen in other risk groups as well, the availability of valuable information sources as well as the support in individual risk reduction strategies and psychological coping mechanisms are mandatory, especially since higher knowledge correlates with dangerousness assessment and might lead to better compliance with preventive behaviours.

Associations between serum cholesterol and immuno-phenotypical characteristics of circulatory B cells and Tregs

Blood lipids play a major role in the manifestation of cardiovascular diseases. Recent research suggested that there are connections between cholesterol levels and immunological alterations. We investigated whether there is an association between serum cholesterol levels (total, HDL, LDL) and immune cells (B cell and regulatory T cells [Tregs]). The analysis was based on data from 231 participants of the MEGA study in Augsburg, Germany, recruited between 2018 and 2021. Most participants was examined two different times within a time period of 9 months. At every visit, fasting venous blood samples were taken. Immune cells were analyzed immediately afterwards using flow cytometry. Using multivariable-adjusted linear regression models, the associations between blood cholesterol concentrations and the relative quantity of several B cell and Treg subsets were analyzed. We found that particularly HDL cholesterol concentrations were significantly associated to some immune cell subpopulations: HDL cholesterol showed significant positive associations with the relative frequency of CD25++ Tregs (as proportion of all CD4+CD25++ T cells) and conventional Tregs (defined as the proportion of CD25+CD127- cells on all CD45RA- CD4+ T cells). Regarding B cells, HDL cholesterol values were inversely associated with the cell surface expression of IgD and with naïve B cells (CD27- IgD+ B cells). In conclusion, HDL cholesterol levels were associated with modifications in the composition of B cell and Tregs subsets demonstrating an important interconnection between lipid metabolism and immune system. Knowing that this association exists might be crucial for a deeper and more comprehensive understanding of the pathophysiology of atherosclerosis.

Sex-specific associations between systolic, diastolic and pulse pressure and hemostatic parameters in the population-based KORA-Fit study: a cross-sectional study

BACKGROUND

Several prior studies postulated an effect of hypertension on coagulation factors. However, population-based studies investigating the sex-specific associations between hypertension and hemostatic parameters are scarce. Therefore, we investigated the relationship between blood pressure and parameters of coagulation, namely activated partial thromboplastin time (aPTT), international normalized ratio (INR), fibrinogen, factor VIII, antithrombin III, protein C, protein S, and D-dimer in men and women from the general population.

METHODS

Based on 803 participants (376 men, 427 women) from the KORA-Fit Study the sex-specific relationship between systolic, diastolic, and pulse pressure and commonly measured coagulation factors were investigated using multivariable-adjusted linear regression models.

RESULTS

Hypertensive males had significantly higher median fibrinogen levels and factor VIII activity in comparison to normotensive males. There was a statistically significant difference between females with and without hypertension regarding the parameter fibrinogen, D-dimers, Protein S activity, and factor VIII activity. In multivariable linear regression analyses no significant association between systolic blood pressure, diastolic blood pressure, as well as pulse pressure and the investigated hemostatic parameters was found in men. In women, a significant positive association could be observed between systolic blood pressure and D-dimer level [β-estimate per mmHg increase 3.37 (95% CI 0.935-5.804; p = 0.007)] and between pulse pressure and D-dimer level [β-estimate per mmHg increase 5.351 (95% CI 1.772-8.930; p = 0.003)].

CONCLUSIONS

It appears that sex differences exist in the association between blood pressure parameters and commonly measured coagulation markers in the general population. Further studies are needed to identify the underlying causes.

Inflammatory plasma proteins predict short-term mortality in patients with an acute myocardial infarction

BACKGROUND

The aim of this study was to investigate the association between inflammatory markers and 28-day mortality in patients with ST-elevation myocardial infarction (STEMI).

METHODS

In 398 STEMI patients recorded between 2009 and 2013 by the population-based Myocardial Infarction Registry Augsburg, 92 protein biomarkers were measured in admission arterial blood samples using the OLINK inflammatory panel. In multivariable-adjusted logistic regression models, the association between each marker and 28-day mortality was investigated. The values of the biomarkers most significantly associated with mortality were standardized and summarized to obtain a prediction score for 28-day mortality. The predictive ability of this biomarker score was compared to the established GRACE score using ROC analysis. Finally, a combined total score was generated by adding the standardized biomarker score to the standardized GRACE score.

RESULTS

The markers IL-6, IL-8, IL-10, FGF-21, FGF-23, ST1A1, MCP-1, 4E-BP1, and CST5 were most significantly associated with 28-day mortality, each with FDR-adjusted (false discovery rate adjusted) p-values of < 0.01 in the multivariable logistic regression model. In a ROC analysis, the biomarker score and the GRACE score showed comparable predictive ability for 28-day mortality (biomarker score AUC: 0.7859 [CI: 0.6735-0.89], GRACE score AUC: 0.7961 [CI: 0.6965-0.8802]). By combining the biomarker score and the Grace score, the predictive ability improved with an AUC of 0.8305 [CI: 0.7269-0.9187]. A continuous Net Reclassification Improvement (cNRI) of 0.566 (CI: 0.192-0.94, p-value: 0.003) and an Integrated Discrimination Improvement (IDI) of 0.083 ((CI: 0.016-0.149, p-value: 0.015) confirmed the superiority of the combined score over the GARCE score.

CONCLUSIONS

Inflammatory biomarkers may play a significant role in the pathophysiology of acute myocardial infarction (AMI) and AMI-related mortality and might be a promising starting point for personalized medicine, which aims to provide each patient with tailored therapy.

Prognostic value of stress hyperglycemia ratio on short- and long-term mortality after acute myocardial infarction

AIMS

Prior studies demonstrated an association between hospital admission blood glucose and mortality in acute myocardial infarction (AMI). Because stress hyperglycemia ratio (SHR) has been suggested as a more reliable marker of stress hyperglycemia this study investigated to what extent SHR in comparison with admission blood glucose is associated with short- and long-term mortality in diabetic and non-diabetic AMI patients.

METHODS

The analysis was based on 2,311 AMI patients aged 25-84 years from the population-based Myocardial Infarction Registry Augsburg (median follow-up time 6.5 years [IQR: 4.9-8.1]). The SHR was calculated as admission glucose (mg/dl)/(28.7 × HbA1c (%)-46.7). Using logistic and COX regression analyses the associations between SHR and admission glucose and mortality were investigated.

RESULT

Higher admission glucose and higher SHR were significantly and nonlinearly associated with higher 28-day mortality in AMI patients with and without diabetes. In patients without diabetes, the AUC for SHR was significantly lower than for admission glucose (SHR: 0.6912 [95%CI 0.6317-0.7496], admission glucose: 0.716 [95%CI 0.6572-0.7736], p-value: 0.0351). In patients with diabetes the AUCs were similar for SHR and admission glucose. Increasing admission glucose and SHR were significantly nonlinearly associated with higher 5-year all-cause mortality in AMI patients with diabetes but not in non-diabetic patients. AUC values indicated a comparable prediction of 5-year mortality for both measures in diabetic and non-diabetic patients.

CONCLUSIONS

Stress hyperglycemia in AMI patients plays a significant role mainly with regard to short-term prognosis, but barely so for long-term prognosis, underlining the assumption that it is a transient dynamic disorder that occurs to varying degrees during the acute event, thereby affecting prognosis.

Association between inflammatory bowel disease and Parkinson's disease: A Mendelian randomization study

Emerging evidence from observational studies suggests an increased risk of Parkinson's disease (PD) in patients with inflammatory bowel disease (IBD). However, to date it is not clear whether a causal relationship exists. To investigate whether IBD is causally related to PD, a two-sample Mendelian randomization study was carried out. Independent genetic instruments from the largest available genome-wide association study (GWAS) for IBD (7045 cases, 456,327 controls) including European participants were used to investigate the association with PD (56,306 cases; 1.4 million controls). The results were validated by using a second IBD sample (12,882 cases; 21,770 controls) including the main subtypes ulcerative colitis (UC; 6968 cases; 20,464 controls) and Crohn's disease (CD; 5956 cases; 14,927 controls). The radial inverse-variance weighted (IVW) approach was used in the primary analysis, and the robustness of the findings were confirmed in a number of sensitivity analyses. Finally, the recently proposed CAUSE approach was performed. There was no evidence of an association between IBD and PD (OR_IVW = 0.98; 95% CI: [0.93; 1.04]; P = 0.48). This finding could be validated using a second sample of IBD cases (OR_IVW = 0.98; 95% CI: [0.95; 1.02]; P = 0.36). Furthermore, MR analyses did not support a causal effect of CD (OR_IVW = 1.00; 95% CI: [0.98; 1.03]; P = 0.96) or UC (OR_IVW = 1.02; 95% CI: [0.98; 1.06]; P = 0.45) on PD. The present study suggests that neither IBD nor its subtypes CD and UC causally affect Parkinson's disease in the European population. Further research is necessary to investigate whether intestinal inflammation impacts the development of PD.

Relationship between atopic dermatitis, depression and anxiety: a two-sample Mendelian randomization study

BACKGROUND

Growing evidence suggests that atopic dermatitis (AD) is associated with an increased risk of depressive disorders and anxiety. However, existing studies were observational and may have uncovered correlations but could not easily disentangle noncausal or reverse-causal associations because these associations could be confounded and may not reflect true causal relationships.

OBJECTIVES

To examine, in a two-sample Mendelian randomization study, the potential effect of AD on the risk of depressive disorders and anxiety.

METHODS

Genetic instruments from the largest available genome-wide association study (GWAS) for AD (10 788 cases and 30 047 controls) were used to investigate the relationship to broad depression (170 756 cases and 329 443 controls), major depressive disorder (MDD; 30 603 cases and 143 916 controls) and anxiety (5580 cases and 11 730 controls). A set of complementary approaches were carried out to assess horizontal pleiotropy and related potential caveats occurring in MR studies.

RESULTS

We observed no causal impact of AD on the risk of depressive disorders and anxiety, with close-to-zero effect estimates. The inverse weighted method revealed no associations of AD on broad depression [odds ratio (OR) 1·014; P = 0·431], probable MDD (OR 1·002; P = 0·568), International Classification of Diseases, Ninth/Tenth Revision-based MDD (OR 1·001; P = 0·466) or anxiety (OR 1·097; P = 0·180).

CONCLUSIONS

This MR study does not support a causal effect of AD on depression and anxiety.

A cost-utility analysis of increasing percutaneous coronary intervention use in elderly patients with acute coronary syndromes in six European countries

AIMS

Percutaneous coronary intervention reduces mortality in acute coronary syndrome patients but the cost-utility of increasing its use in elderly acute coronary syndrome patients is unknown.

METHODS

We assessed the efficiency of increased percutaneous coronary intervention use compared to current practice in patients aged ≥75 years admitted for acute coronary syndrome in France, Germany, Greece, Italy, Portugal and Spain with a semi-Markov state transition model. In-hospital mortality reduction estimates by percutaneous coronary intervention use and costs were derived from the EUROpean Treatment & Reduction of Acute Coronary Syndromes cost analysis EU project (n = 28,600). Risk of recurrence and out-of-hospital all-cause mortality were obtained from the Information System for the Development of Research in Primary Care (SIDIAP) database from North-Eastern Spain (n = 55,564). In-hospital mortality was modelled using stratified propensity score analysis. The 8-year acute coronary syndrome recurrence risk and out-of-hospital mortality were estimated with a multistate survival model. The scenarios analysed were to increase percutaneous coronary intervention use among patients with the highest, moderate and lowest probability of receiving percutaneous coronary intervention based on the propensity score analysis.

RESULTS

France, Greece and Portugal showed similar total costs/1000 individuals (7.29-11.05 m €); while in Germany, Italy and Spain, costs were higher (13.53-22.57 m €). Incremental cost-utility ratios of providing percutaneous coronary intervention to all patients ranged from 2262.8 €/quality adjusted life year gained for German males to 6324.3 €/quality adjusted life year gained for Italian females. Increasing percutaneous coronary intervention use was cost-effective at a willingness-to-pay threshold of 10,000 €/quality adjusted life year gained for all scenarios in the six countries, in males and females.

CONCLUSION

Compared to current clinical practice, broadening percutaneous coronary intervention use in elderly acute coronary syndrome patients would be cost-effective across different healthcare systems in Europe, regardless of the selected strategy.

Prediabetes is associated with microalbuminuria, reduced kidney function and chronic kidney disease in the general population: The KORA (Cooperative Health Research in the Augsburg Region) F4-Study

BACKGROUND AND AIMS

We investigated the associations of serum fasting (FG) and 2-h postload (2HG) glucose from an oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), fasting insulin and the homeostasis model assessment-insulin resistance index (HOMA-IR) with urinary albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR).

METHODS AND RESULTS

We performed cross-sectional analyses of 2713 subjects (1429 women; 52.7%) without known type 2 diabetes, aged 31-82 years, from the KORA (Cooperative Health Research in the Augsburg Region) F4-Study. FG, 2HG, HbA1c, fasting insulin, HOMA-IR and glucose tolerance categories were analyzed for association with ACR and eGFR in multivariable adjusted linear and median regression models, and with isolated microalbuminuria (i-MA), isolated reduced kidney function (i-RKF) and chronic kidney disease (CKD, defined as MA and/or RKF) in multivariable adjusted logistic regression models. Among the 2713 study participants, 28% revealed prediabetes (isolated impaired fasting glucose [i-IFG], isolated glucose tolerance [i-IGT] or both by American Diabetes Association definition), 4.2% had unknown type 2 diabetes, 6.5% had i-MA, 3.1% i-RKF and 10.9% CKD. In multivariable adjusted analysis, all continuous variables (FG, 2HG, HbA1c, fasting insulin and HOMA-IR) were associated with i-MA, i-RKF and CKD. The odds ratios (ORs) for i-MA and CKD were 1.54 (95% confidence interval: 1.02-2.33) and 1.58 (1.10-2.25) for individuals with i-IFG. Moreover, the OR for i-RKF was 2.57 (1.31-5.06) for individuals with IFG + IGT.

CONCLUSION

Our findings suggest that prediabetes might have harmful effects on the kidney.

Sex differences in the association of social network satisfaction and the risk for type 2 diabetes

Background

The role of an individual’s social network satisfaction (SNS) in the association of social isolation or living alone and incident type 2 diabetes (T2D) is unclear. We assessed the association of SNS with incident T2D and analysed potential modifications of the SNS-T2D association by social isolation or living alone.

Methods

The study population (N = 6839 aged 25–74 years without diabetes at baseline) derived from the prospective population-based MONICA/KORA study (1989–2009). Social network satisfaction was assessed by a single item. Cox regression was used to estimate hazard ratios (HR) for SNS separately in men and women.

Results

In men with low SNS, risk for incident T2D increased significantly (HR: 2.15, 95% CI: 1.33–3.48, p value 0.002). After additional adjustments for social isolation or living alone, the risk for incident T2D was still significant, albeit less pronounced (HRs 1.85 or 2.05, p values 0.001 or 0.004). The interaction analysis showed an increased T2D risk effect for low SNS compared to high SNS in women living in a partnership (HR: 2.11, 95% CI: 1.00–4.44, p value for interaction: 0.047) and for moderate SNS compared to high SNS in socially connected women (1.56, 1.01–2.39, 0.010).

Conclusions

Further research is needed to address the complexities of the perception of social relationships and social interactions, or interdependence, especially when another major public health issue such as T2D is concerned.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4323-7) contains supplementary material, which is available to authorized users.

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.

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.

[From the MONICA-project via KORA to the NAKO-study: Practical Utility of Epidemiological Studies in Augsburg Region]

The objective of the WHO-MONICA study was to determine the influence of changing risk factors and treatment options on myocardial infarction rates in populations in a 10-year time period. For this purpose, a population-based myocardial infarction registry was established in 1984 in Augsburg (covering the city of Augsburg and 2 adjacent counties) in order to continuously register all inhabitants of the region who had a myocardial infarction during the study period. In addition, three cross-sectional studies based on random population samples (1984/85, 1989/90 and 1994/95) were carried out. Our data revealed a continuous decrease of myocardial infarction incidence and demonstrated that the decrease of coronary mortality can be ascribed to decreasing myocardial infarction incidence and longer survival after myocardial infarction. Until today the myocardial infarction registry continues to be a permanent part of the Cooperative Health Research in the Region of Augsburg (KORA). Moreover, within the framework of KORA, a fourth population-based cross-sectional study was carried out in 1999/2001. Meanwhile, more than 18 000 study participants have been followed-up for specific endpoints for up to 30 years. A large number of publications, which address cardiovascular diseases, type 2 diabetes mellitus, lung diseases, environmental and genetic questions, health services research and numerous other topics, are based on the KORA study. Today we know that the development of chronic diseases can be ascribed to a complex interaction of social factors, health policy conditions, health behavior, risk factors and molecular mechanisms. To tackle the challenges posed by these multiple factors in Germany, NAKO (Nationale Kohorte), the largest nation-wide long-term study so far, was initiated. Within the framework of the NAKO study, 200 000 persons aged between 20 and 69 years in Germany - thereof 20 000 persons in the region of Augsburg - will be examined and interviewed in the next 10 years, and widespread diseases will be investigated with modern epidemiological methods. The results of these epidemiological long-term studies will contribute to the prevention, early diagnosis and best possible treatment of widespread diseases.

Poor structural social support is associated with an increased risk of Type 2 diabetes mellitus: findings from the MONICA/KORA Augsburg cohort study

AIMS

Several psychosocial factors have been shown to increase the risk of Type 2 diabetes mellitus. This study investigated the association between structural social support and incidence of Type 2 diabetes mellitus in men and women.

METHODS

Data were derived from three population-based MONICA/KORA surveys conducted in 1984-1995 in the Augsburg region (southern Germany) and followed up by 2009. The study population comprised 8952 participants (4669 men/4283 women) aged 30-74 years without diabetes at baseline. Structural social support was assessed using the Social Network Index. Sex-specific hazard ratios were estimated from Cox proportional hazard models.

RESULTS

Within follow-up, 904 incident Type 2 diabetes mellitus cases (558 men, 346 women) were observed. Crude incidence rates for Type 2 diabetes mellitus per 10 000 person-years were substantially higher in poor compared with good structural social support (men: 94 vs. 69, women: 58 vs. 43). After adjustment for age, survey, parental history of diabetes, smoking status, alcohol intake, physical activity, hypertension, dyslipidaemia, BMI, education, sleep complaints and depressed mood, risk of Type 2 diabetes mellitus for participants with poor compared with good structural social support was 1.31 [95% confidence interval (CI) = 1.11-1.55] in men and 1.10 (95% CI = 0.88-1.37) in women. Stratified analyses revealed a hazard ratio of 1.50 (95% CI = 1.23-1.83) in men with a low level of education and 0.87 (95% CI = 0.62-1.22) in men with a high level of education (P for interaction: 0.0082).

CONCLUSIONS

Poor structural social support is associated with Type 2 diabetes mellitus in men. This association is independent of risk factors at baseline and is particularly pronounced in men with a low level of education.

Low serum omentin levels in the elderly population with Type 2 diabetes and polyneuropathy

AIMS

To investigate the hypothesis that high serum levels of omentin, an adipokine with anti-inflammatory, insulin-sensitizing and cardioprotective properties, may be related to a lower risk of diabetic sensorimotor polyneuropathy.

METHODS

The association between serum omentin level and polyneuropathy was estimated in people aged 61-82 years with Type 2 diabetes (47 with and 168 without polyneuropathy) from the population-based KORA F4 study. The presence of clinical diabetic sensorimotor polyneuropathy was defined as bilateral impairment of foot vibration perception and/or foot pressure sensation. Omentin levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum omentin level was inversely associated with polyneuropathy after adjustment for age, sex, height, waist circumference, hypertension, total cholesterol, smoking, alcohol intake and physical activity [odds ratio 0.45 (95% CI 0.21-0.98); P = 0.043]. Although omentin was positively correlated with adiponectin (r = 0.55, P < 0.0001) and inversely with tumour necrosis factor-α (r = -0.30, P = 0.019), additional adjustment for adiponectin and tumour necrosis factor-α had little impact on the association.

CONCLUSIONS

Serum levels of omentin are reduced in people with Type 2 diabetes and diabetic sensorimotor polyneuropathy, independently of established risk factors of polyneuropathy. This association is only partially explained by biomarkers of subclinical inflammation.

Association between apolipoprotein A-IV concentrations and chronic kidney disease in two large population-based cohorts: results from the KORA studies

BACKGROUND

Apolipoprotein A-IV (apoA-IV) is an anti-atherogenic and antioxidative glycoprotein. Plasma apoA-IV levels are elevated in patients with primary chronic kidney disease (CKD) or renal failure. The association between apoA-IV and kidney function has not been investigated in the general population; therefore, we analysed this relationship in two large population-based cohorts.

METHODS

Plasma apoA-IV concentrations were measured in the Cooperative Health Research in the Region of Augsburg (KORA) F3 (n = 3159) and KORA F4 (n = 3061) studies. CKD was defined by the serum creatinine-estimated glomerular filtration rate (eGFR) and/or urine albumin-to-creatinine ratio.

RESULTS

Mean (±SD) apoA-IV concentration was 17.3 ± 4.7 mg dL(-1) in KORA F3 and 15.3 ± 4.3 mg dL(-1) in KORA F4. Fully adjusted linear mixed models revealed a significant association between apoA-IV concentration and lower eGFR in the third and fourth versus the first quartile of apoA-IV (β = -1.78 mL min(-1) /1.73 m², P = 0.0003 and β = -5.09 mL min(-1) /1.73 m², P = 2.83 × 10(-23) , respectively). ApoA-IV was significantly associated with an eGFR of <60 mL min(-1) /1.73 m², which was observed in 601 of the 6220 study participants [odds ratio (OR) 1.46, P = 0.03 and OR 3.47, P = 6.84 × 10(-15) for the third and fourth vs. the first quartile of apoA-IV, respectively]. Adding apoA-IV (fourth vs. first quartile) to the fully adjusted model significantly improved discrimination of eGFR <60 mL min(-1) /1.73 m² in KORA F3 [integrated discrimination improvement (IDI) 0.03, P = 1.30 × 10(-7) ] and KORA F4 (IDI 0.04, P = 1.32 × 10(-9) ) beyond classical risk factors for CKD.

CONCLUSION

The present analysis in two population-based cohorts revealed that high plasma apoA-IV concentrations are strongly associated with low kidney function defined by eGFR independent of major CKD risk factors. ApoA-IV appears to be an early marker of impaired kidney function.

Feasibility and quality development of biomaterials in the pretest studies of the German National Cohort

BACKGROUND

The German National Cohort (GNC) is designed to address research questions concerning a wide range of possible causes of major chronic diseases (e.g. cancer, diabetes, infectious, allergic, neurologic and cardiovascular diseases) as well as to identify risk factors and prognostic biomarkers for early diagnosis and prevention of these diseases. The collection of biomaterials in combination with extensive information from questionnaires and medical examinations represents one of the central study components.

OBJECTIVES

In two pretest studies of the German National Cohort conducted between 2011 and 2013, a range of biomaterials from a defined number of participants was collected. Ten study centres were involved in pretest 1 and 18 study centres were involved in pretest 2. Standard operation procedures (SOP) were developed and evaluated to minimize pre-analytical artefacts during biosample collection. Within the pretest studies different aspects concerning feasibility of sample collection/preparation [pretest 1 (a)] and quality control of biomarkers and proteome analyses were investigated [pretest 1 (b), (c)]. Additionally, recruitment of study participants for specific projects and examination procedures of all study centres in a defined time period according to common standards as well as transportation and decentralized storage of biological samples were tested (pretest 2). These analyses will serve as the basis for the biomaterial collection in the main study of the GNC starting in 2014.

MATERIALS AND METHODS

Participants, randomly chosen from the population (n = 1000 subjects recruited at ten study sites in pretest 1) were asked to donate blood, urine, saliva and stool samples. Additionally, nasal and oropharyngeal swabs were collected at the study sites and nasal swabs were collected by the participants at home. SOPs for sample collection, preparation, storage and transportation were developed and adopted for pretest 2. In pretest 2, 18 study sites (n = 599 subjects) collected biomaterials mostly identical to pretest 1. Biomarker analyses to test the quality of the biomaterials were performed.

RESULTS

In pretest 1 and 2, it was feasible to collect all biomaterials from nearly all invited participants without major problems. The mean response rate of the subjects was 95 %. As one important result we found for example that after blood draw the cellular fraction should be separated from the plasma and serum fractions during the first hour with no significant variation for up to 6 h at 4 ℃ for all analysed biomarkers. Moreover, quality control of samples using a proteomics approach showed no significant clustering of proteins according to different storage conditions. All developed SOPs were validated for use in the main study after some adaptation and modification. Additionally, electronic and paper documentation sheets were developed and tested to record time stamps, volumes, freezing times, and aliquot numbers of the collected biomaterials.

DISCUSSION

The collection of the biomaterials was feasible without major problems at all participating study sites. However, the processing times were in some cases too long. To avoid pre-analytical artefacts in sample collection, appropriate standardisation among the study sites is necessary. To achieve this, blood and urine collection will have to be adapted to specific conditions of usage of liquid handling robots, which will be available at all participating study centres in the main study of the GNC. Strict compliance with the SOPs, thorough training of the staff and accurate documentation are mandatory to obtain high sample quality for later analyses. The so obtained biomaterials represent a valuable resource for research on infectious and other common complex diseases in the GNC.

Association of neighbourhood unemployment rate with incident Type 2 diabetes mellitus in five German regions

AIM

To analyse the association of neighbourhood unemployment with incident self-reported physician-diagnosed Type 2 diabetes in a population aged 45-74 years from five German regions.

METHODS

Study participants were linked via their addresses at baseline to particular neighbourhoods. Individual-level data from five population-based studies were pooled and combined with contextual data on neighbourhood unemployment. Type 2 diabetes was assessed according to a self-reported physician diagnosis of diabetes. We estimated proportional hazard models (Weibull distribution) in order to obtain hazard ratios and 95% CIs of Type 2 diabetes mellitus, taking into account interval-censoring and clustering.

RESULTS

We included 7250 participants residing in 228 inner city neighbourhoods in five German regions in our analysis. The incidence rate was 12.6 per 1000 person-years (95% CI 11.4-13.8). The risk of Type 2 diabetes mellitus was higher in men [hazard ratio 1.79 (95% CI 1.47-2.18)] than in women and higher in people with a low education level [hazard ratio 1.55 (95% CI 1.18-2.02)] than in those with a high education level. Independently of individual-level characteristics, we found a higher risk of Type 2 diabetes mellitus in neighbourhoods with high levels of unemployment [quintile 5; hazard ratio 1.72 (95% CI 1.23-2.42)] than in neighbourhoods with low unemployment (quintile 1).

CONCLUSIONS

Low education level and high neighbourhood unemployment were independently associated with an elevated risk of Type 2 diabetes mellitus. Studies examining the impact of the residential environment on Type 2 diabetes mellitus will provide knowledge that is essential for the identification of high-risk populations.

Association between muscular strength and inflammatory markers among elderly persons with cardiac disease: results from the KORA-Age study

Little is known about the association between muscle strength and inflammation in diseased individuals and particularly in cardiac patients. Thus, our purpose was to examine the association of muscular strength with the inflammatory status in older adults with and without cardiac disease. The cross-sectional analysis was based on 1079 adults aged 65-94 years, who participated in the KORA-Age study. Participants underwent an interview and extensive physical examinations including anthropometric measurements, registration of diseases and drug intake, determination of health-related behaviors, collection of blood samples for measurements of interleukin-6 and hs-CRP and muscle strength measurement using hand-grip dynamometry. Cardiac patients (n = 323) had higher levels of IL-6 and poorer muscle strength compared with older adults without cardiac disease. Among persons with cardiac diseases, muscle strength in the lower tertile compared to the upper tertile was significantly associated with increased odds of having elevated IL-6 levels (OR 3.53, 95 % CI 1.18-10.50, p = 0.024) after controlling for age, gender, body fat, alcohol intake, smoking status, diseases, medications and physical activity, whereas the association between muscle strength and hs-CRP remained borderline significant (OR 2.80, 95 % CI 0.85-9.24, p = 0.092). The same trends, with slightly lower odds ratios, were also observed in older adults without cardiac disease. Lower levels of muscular strength are associated with higher concentrations of IL-6 and hs-CRP in elderly individuals with and without cardiac disease suggesting a significant contribution of the muscular system in reducing low-grade inflammation that accompanies cardiac disease and aging.

Health-related quality of life in women and men with type 2 diabetes: a comparison across treatment groups

AIM

This study compares health-related quality of life (HRQL) in patients with type 2 diabetes (T2DM) across treatment groups and explores gender differences.

METHODS

Four regional surveys (KORA, CARLA, SHIP, DHS) and a national survey (GNHIES98) were pooled at individual level. HRQL was assessed with the SF-12/-36v1. Linear regression models were used to assess the effect of T2DM by treatment type (no medication; oral; oral/insulin combination; insulin) on the physical (PCS-12) and mental summary score (MCS-12) and the SF-6D, controlling for age, sex, study and covariates. We also performed an explanatory analysis of single items.

RESULTS

PCS-12 scores and treatment type were associated (P-value 0.006), with lowest values for insulin treatment (-4.44 vs. oral; -4.41 vs. combination). MCS-12 scores were associated with treatment type and gender (P-value <0.012), with lower scores for women undergoing oral (-4.25 vs. men) and combination treatment (-6.99 vs. men). Similar results were observed for SF-6D utilities and single items, related to mental health, social functioning, vitality and role limitation (emotional). Comorbidities were predictors of lower PCS-12 and SF-6D scores.

CONCLUSIONS

T2DM treatment impacts differently on physical and mental HRQL and on women and men. Further studies of gender-specific perceptions of T2DM treatment regimens are needed.

A clinical screening score for diabetic polyneuropathy: KORA F4 and AusDiab studies

AIMS

Since screening for distal sensorimotor polyneuropathy (DSPN) in individuals with diabetes is being underused, our aim was to develop a clinical screening score for identifying individuals with DSPN.

METHODS

All participants with type 2 diabetes and aged 61-82 years from the German population-based KORA F4 Study (n=177) and the Australian population-based AusDiab Study (n=244) were combined into one study sample. Risk indicators of DSPN were identified and entered into a stepwise model-selection procedure, constructing two consecutive scores with increasing complexity (a base and clinical model).

RESULTS

The prevalence of DSPN was 18.2% (95% confidence interval (CI): 14.7-22.3). The base model comprised age (years), height (cm), weight (kg), pain or discomfort in the feet and/or legs (yes/no), and duration of diabetes (years), yielding an area under the receiver operating characteristics curve (AUC) of 0.80 (95% CI: 0.76-0.85). The clinical model additionally included diastolic blood pressure (mmHg) and serum creatinine levels (mmol/l). The AUC increased only marginally to 0.82 (0.77-0.87) (p for AUC comparison=0.188). The internal validation of the scores produced similar AUCs.

CONCLUSIONS

The screening scores developed in this study are a simple tool to differentiate between a high and low likelihood of having DSPN among individuals with type 2 diabetes.

Increased amino acids levels and the risk of developing of hypertriglyceridemia in a 7-year follow-up

BACKGROUND

Recently, five branched-chain and aromatic amino acids were shown to be associated with the risk of developing type 2 diabetes (T2D).

AIM

We set out to examine whether amino acids are also associated with the development of hypertriglyceridemia.

MATERIALS AND METHODS

We determined the serum amino acids concentrations of 1,125 individuals of the KORA S4 baseline study, for which follow-up data were available also at the KORA F4 7 years later. After exclusion for hypertriglyceridemia (defined as having a fasting triglyceride level above 1.70 mmol/L) and diabetes at baseline, 755 subjects remained for analyses.

RESULTS

Increased levels of leucine, arginine, valine, proline, phenylalanine, isoleucine and lysine were significantly associated with an increased risk of hypertriglyceridemia. These associations remained significant when restricting to those individuals who did not develop T2D in the 7-year follow-up. The increase per standard deviation of amino acid level was between 26 and 40 %.

CONCLUSIONS

Seven amino acids were associated with an increased risk of developing hypertriglyceridemia after 7 years. Further studies are necessary to elucidate the complex role of these amino acids in the pathogenesis of metabolic disorders.

Development and validation of an ankle brachial index risk model for the prediction of cardiovascular events

BACKGROUND

The ankle brachial index (ABI) is related to risk of cardiovascular events independent of the Framingham risk score (FRS). The aim of this study was to develop and evaluate a risk model for cardiovascular events incorporating the ABI and FRS.

DESIGN

An analysis of participant data from 18 cohorts in which 24,375 men and 20,377 women free of coronary heart disease had ABI measured and were followed up for events.

METHODS

Subjects were divided into a development and internal validation dataset and an external validation dataset. Two models, comprising FRS and FRS + ABI, were fitted for the primary outcome of major coronary events.

RESULTS

In predicting events in the external validation dataset, C-index for the FRS was 0.672 (95% CI 0.599 to 0.737) in men and 0.578 (95% CI 0.492 to 0.661) in women. The FRS + ABI led to a small increase in C-index in men to 0.685 (95% CI 0.612 to 0.749) and large increase in women to 0.690 (95% CI 0.605 to 0.764) with net reclassification improvement (NRI) of 4.3% (95% CI 0.0 to 7.6%, p = 0.050) and 9.6% (95% CI 6.1 to 16.4%, p < 0.001), respectively. Restricting the FRS + ABI model to those with FRS intermediate 10-year risk of 10 to 19% resulted in higher NRI of 15.9% (95% CI 6.1 to 20.6%, p < 0.001) in men and 23.3% (95% CI 13.8 to 62.5%, p = 0.002) in women. However, incorporating ABI in an improved newly fitted risk factor model had a nonsignificant effect: NRI 2.0% (95% CI 2.3 to 4.2%, p = 0.567) in men and 1.1% (95% CI 1.9 to 4.0%, p = 0.483) in women.

CONCLUSIONS

An ABI risk model may improve prediction especially in individuals at intermediate risk and when performance of the base risk factor model is modest.

Medication costs by glucose tolerance stage in younger and older women and men: results from the population-based KORA survey in Germany

To estimate medication costs in individuals with diagnosed diabetes, undetected diabetes, impaired glucose regulation and normal blood glucose values in a population-based sample by age and sex.Using the KORA F4 follow-up survey, conducted in 2006-2008 (n=2611, age 40-82 years), we identified individuals' glucose tolerance status by means of an oral glucose tolerance test. We assessed all medications taken regularly, calculated age-sex specific medication costs and estimated cost ratios for total, total without antihyperglycemic drugs, and cardiovascular medication, using multiple 2-part regression models.Compared to individuals with normal glucose values, costs were increased in known diabetes, undetected diabetes and impaired glucose regulation, which was more pronounced in participants aged 40-59 years than in those aged 60-82 years (cost ratios for all medications: 40-59 years: 2.85; 95%-confidence interval: 1.78-4.54, 2.00; 1.22-3.29 and 1.53; 1.12-2.09; 60-82 years: 2.04; 1.71-2.43, 1.17; 0.90-1.51 and 1.09; 0.94-1.28). Compared to individuals with diagnosed diabetes, costs were significantly lower among individuals with impaired glucose regulation across all age and sex strata, also when antihyperglycemic medication was excluded (40-59 years: 0.60; 0.36-0.98, 60-82 years: 0.74; 0.60-0.90; men: 0.72; 0.56-0.93; women: 0.72; 0.54-0.96).We could quantify age- and sex-specific medication costs and cost ratios in individuals with diagnosed diabetes, undetected diabetes and impaired glucose regulation compared to those with normal glucose values, using data of a population-based sample, with oral glucose tolerance test-based identification of diabetes states. These results may help to validly estimate cost-effectiveness of screening and early treatment or prevention of diabetes.

Patient time costs attributable to healthcare use in diabetes: results from the population-based KORA survey in Germany

AIMS

Patient time costs have been described to be substantial; however, data are highly limited. We estimated patient time costs attributable to outpatient and inpatient care in study participants with diagnosed diabetes, previously undetected diabetes, impaired glucose regulation and normal glucose tolerance.

METHODS

Using data of the population-based KORA S4 study (55-74 years, random sample of n = 350), we identified participants' stage of glucose tolerance by oral glucose tolerance test. To estimate mean patient time costs per year (crude and standardized with respect to age and sex), we used data regarding time spent with ambulatory visits including travel and waiting time and with hospital stays (time valued at a 2011 net wage rate of €20.63/h). The observation period was 24 weeks and data were extrapolated to 1 year.

RESULTS

Eighty-nine to 97% of participants in the four groups (diagnosed diabetes, undetected diabetes, impaired glucose regulation and normal glucose tolerance.) had at least one physician contact and 4-14% at least one hospital admission during the observation period. Patient time [h/year (95% CI)] was 102.0 (33.7-254.8), 53.8 (15.0-236.7), 59.3 (25.1-146.8) and 28.6 (21.1-43.7), respectively. Age-sex standardized patient time costs per year (95% CI) were €2447.1 (804.5-6143.6), €880.4 (259.1-3606.7), €1151.6 (454.6-2957.6) and €589.2 (435.8-904.8).

CONCLUSIONS

Patient time costs were substantial--even higher than medication costs in the same study population. They are higher in participants with diagnosed diabetes, but also in those with undetected diabetes and impaired glucose regulation compared with those with normal glucose tolerance. Research is needed in larger populations to receive more precise and certain estimates that can be used in health economic evaluation.

Long-term exposure to traffic-related air pollution and insulin resistance in children: results from the GINIplus and LISAplus birth cohorts

AIMS/HYPOTHESIS

Epidemiological studies that have examined associations between long-term exposure to traffic-related air pollution and type 2 diabetes mellitus in adults are inconsistent, and studies on insulin resistance are scarce. We aimed to assess the association between traffic-related air pollution and insulin resistance in children.

METHODS

Fasting blood samples were collected from 397 10-year-old children in two prospective German birth cohort studies. Individual-level exposures to traffic-related air pollutants at the birth address were estimated by land use regression models. The association between air pollution and HOMA of insulin resistance (HOMA-IR) was analysed using a linear model adjusted for several covariates including birthweight, pubertal status and BMI. Models were also further adjusted for second-hand smoke exposure at home. Sensitivity analyses that assessed the impact of relocating, study design and sex were performed.

RESULTS

In all crude and adjusted models, levels of insulin resistance were greater in children with higher exposure to air pollution. Insulin resistance increased by 17.0% (95% CI 5.0, 30.3) and 18.7% (95% CI 2.9, 36.9) for every 2SDs increase in ambient NO2 and particulate matter ≤10 μm in diameter, respectively. Proximity to the nearest major road increased insulin resistance by 7.2% (95% CI 0.8, 14.0) per 500 m.

CONCLUSIONS/INTERPRETATION

Traffic-related air pollution may increase the risk of insulin resistance. Given the ubiquitous nature of air pollution and the high incidence of insulin resistance in the general population, the associations examined here may have potentially important public health effects despite the small/moderate effect sizes observed.

The impact of regional deprivation and individual socio-economic status on the prevalence of Type 2 diabetes in Germany. A pooled analysis of five population-based studies

AIM

Our objective was to test the hypothesis that the prevalence of Type 2 diabetes increases with increasing regional deprivation even after controlling for individual socio-economic status.

METHODS

We pooled cross-sectional data from five German population-based studies. The data set contained information on n = 11,688 study participants (men 50.1%) aged 45-74 years, of whom 1008 people had prevalent Type 2 diabetes (men 56.2%). Logistic multilevel regression was performed to estimate odds ratios (OR) and 95% confidence intervals (CI) for diabetes prevalence. We controlled for sex, age and lifestyle risk factors, individual socio-economic status and regional deprivation, based on a new small-area deprivation measure, the German Index of Multiple Deprivation.

RESULTS

Adjusted for sex, age, body mass index (BMI), physical activity, smoking status and alcohol consumption, the prevalence of Type 2 diabetes showed a stepwise increase in risk with increasing area deprivation [OR 1.88 (95% CI 1.16-3.04) in quintile 4 and OR 2.14 (95% CI 1.29-3.55) in quintile 5 compared with the least deprived quintile 1], even after controlling for individual socio-economic status. Focusing on individual socio-economic status alone, the risk of having diabetes was significantly higher for low compared with medium or high educational level [OR 1.46 (95% CI 1.24-1.71)] and for the lowest compared with the highest income group [OR 1.53 (95% CI 1.18-1.99)].

CONCLUSION

Regional deprivation plays a significant part in the explanation of diabetes prevalence in Germany independently of individual socio-economic status. The results of the present study could help to target public health measures in deprived regions.

Serum potassium is associated with prediabetes and newly diagnosed diabetes in hypertensive adults from the general population: the KORA F4-study

AIMS/HYPOTHESIS

Evidence suggests that low serum potassium concentrations or hypokalaemia induced by the intake of diuretics are associated with incident diabetes and increased risk for diabetes in persons with hypertension. We examined a possible association between serum potassium and prediabetes (defined as isolated impaired fasting glucose [i-IFG], isolated impaired glucose tolerance [i-IGT] or combined IFG/IGT), as well as known and newly diagnosed diabetes (NDD), in 32- to 81-year-old men and women with and without hypertension.

METHODS

This cross-sectional analysis was based on 2,948 participants in the Cooperative Health Research in the Region of Augsburg (KORA) F4 study conducted in 2006-2008 in southern Germany. Serum concentrations of potassium were measured by indirect potentiometry.

RESULTS

In the total sample there was no association between serum potassium concentrations and prediabetes. In hypertensive persons however serum potassium levels in the first and second quartile compared with the highest quartile were independently significantly associated with prediabetes after multivariable adjustment (OR for prediabetes, 2.02 [95% CI 1.27, 3.21] for quartile 2 and 2.00 [95% CI 1.27, 3.15] for quartile 1), while in persons without hypertension no association was found. In multinomial logistic regression analysis these findings could be confirmed. In hypertensive participants after multivariable adjustment the associations were statistically significant for i-IGT and NDD (i-IGT OR 1.23; NDD OR 1.41). However, in non-hypertensive persons, all associations between serum potassium levels and each of the categories of impaired glucose regulation were non-significant.

CONCLUSIONS/INTERPRETATION

Serum potassium levels were independently associated with prediabetes and NDD in hypertensive adults from the general population.