The accumulation of deficits approach to describe frailty

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

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

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

Metabolite ratios as potential biomarkers for type 2 diabetes: a DIRECT study

AIMS/HYPOTHESIS

Circulating metabolites have been shown to reflect metabolic changes during the development of type 2 diabetes. In this study we examined the association of metabolite levels and pairwise metabolite ratios with insulin responses after glucose, glucagon-like peptide-1 (GLP-1) and arginine stimulation. We then investigated if the identified metabolite ratios were associated with measures of OGTT-derived beta cell function and with prevalent and incident type 2 diabetes.

METHODS

We measured the levels of 188 metabolites in plasma samples from 130 healthy members of twin families (from the Netherlands Twin Register) at five time points during a modified 3 h hyperglycaemic clamp with glucose, GLP-1 and arginine stimulation. We validated our results in cohorts with OGTT data (n = 340) and epidemiological case-control studies of prevalent (n = 4925) and incident (n = 4277) diabetes. The data were analysed using regression models with adjustment for potential confounders.

RESULTS

There were dynamic changes in metabolite levels in response to the different secretagogues. Furthermore, several fasting pairwise metabolite ratios were associated with one or multiple clamp-derived measures of insulin secretion (all p < 9.2 × 10^-7). These associations were significantly stronger compared with the individual metabolite components. One of the ratios, valine to phosphatidylcholine acyl-alkyl C32:2 (PC ae C32:2), in addition showed a directionally consistent positive association with OGTT-derived measures of insulin secretion and resistance (p ≤ 5.4 × 10^-3) and prevalent type 2 diabetes (OR_{Val_PC ae C32:2} 2.64 [β 0.97 ± 0.09], p = 1.0 × 10^-27). Furthermore, Val_PC ae C32:2 predicted incident diabetes independent of established risk factors in two epidemiological cohort studies (HR_{Val_PC ae C32:2} 1.57 [β 0.45 ± 0.06]; p = 1.3 × 10^-15), leading to modest improvements in the receiver operating characteristics when added to a model containing a set of established risk factors in both cohorts (increases from 0.780 to 0.801 and from 0.862 to 0.865 respectively, when added to the model containing traditional risk factors + glucose).

CONCLUSIONS/INTERPRETATION

In this study we have shown that the Val_PC ae C32:2 metabolite ratio is associated with an increased risk of type 2 diabetes and measures of insulin secretion and resistance. The observed effects were stronger than that of the individual metabolites and independent of known risk factors.

Modulation of circulating vasoactive peptides and extracellular matrix proteins are two novel mechanisms in the cardioprotective action of acarbose

BACKGROUND

Acarbose, an alpha-glucosidase inhibitor, unexpectedly reduced the incidence of hypertension and cardiovascular endpoints in the STOP-NIDDM study. Based on the growing evidence of a link between vasoregulatory peptides and metabolic traits, we hypothesized that changes of the Glycemic Index by acarbose may modulate vasoregulatory peptide levels via regulation of postprandial metabolism.

METHODS

Subjects with type 2 diabetes and with metabolic syndrome were treated with acarbose (12 weeks, 300mg/d) in a double-blind, placebo-controlled, cross-over intervention. Changes in fasting and postprandial levels of midregional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro-endothelin-1 (CT-proET-1) and midregional pro-adrenomedullin (MR-proADM), WNT1 Inducible Signaling Pathway Protein 1 (WISP1) as well as fasting and postprandial glucose/insulin levels in the liquid meal test were assessed.

RESULTS

Acarbose strongly decreased postprandial insulin concentrations in subjects with metabolic syndrome (P=0.004), and postprandial glucose excursions in both groups. Postprandial MR-proANP and CT-proET-1 levels increased after acarbose treatment (P<0.01 and P<0.05, respectively) in subjects with metabolic syndrome only. No effect of acarbose treatment on MR-prADM was observed in both groups. All three peptides were correlated with each over, but neither with insulin sensitivity in euglycemic clamps, nor with adiponectin levels. WISP1 decreased after acarbose treatment in subjects with metabolic syndrome.

CONCLUSIONS

Plasma MR- proANP and CT-proET-1 concentrations, but not MR-prADM concentrations, were affected by treatment with acarbose over 12 weeks. Our findings provide new possible mechanisms of acarbose action in diabetes and metabolic syndrome.

Hepatic insulin clearance is closely related to metabolic syndrome components

OBJECTIVE

Insulin clearance is decreased in type 2 diabetes mellitus (T2DM) for unknown reasons. Subjects with metabolic syndrome are hyperinsulinemic and have an increased risk of T2DM. We aimed to investigate the relationship between hepatic insulin clearance (HIC) and different components of metabolic syndrome and tested the hypothesis that HIC may predict the risk of metabolic syndrome.

RESEARCH DESIGN AND METHODS

Individuals without diabetes from the Metabolic Syndrome Berlin Brandenburg (MeSyBePo) study (800 subjects with the baseline examination and 189 subjects from the MeSyBePo recall study) underwent an oral glucose tolerance test (OGTT) with assessment of insulin secretion (insulin secretion rate [ISR]) and insulin sensitivity. Two indices of HIC were calculated.

RESULTS

Both HIC indices showed lower values in subjects with metabolic syndrome (P < 0.001) at baseline. HIC indices correlate inversely with waist circumference, diastolic blood pressure, fasting glucose, triglycerides, and OGTT-derived insulin secretion index. During a mean follow-up of 5.1 ± 0.9 years, 47 individuals developed metabolic syndrome and 33 subjects progressed to impaired glucose metabolism. Both indices of HIC showed a trend of an association with increased risk of metabolic syndrome (HICC-peptide odds ratio 1.13 [95% CI 0.97-1.31], P = 0.12, and HICISR 1.38 [0.88-2.17], P = 0.16) and impaired glucose metabolism (HICC-peptide 1.12 [0.92-1.36], P = 0.26, and HICISR 1.31 [0.74-2.33] P = 0.36), although point estimates reached no statistical significance.

CONCLUSIONS

HIC was associated with different components of metabolic syndrome and markers of insulin secretion and insulin sensitivity. Decreased HIC may represent a novel pathophysiological mechanism of the metabolic syndrome, which may be used additionally for early identification of high-risk subjects.

Effects of acarbose treatment on markers of insulin sensitivity and systemic inflammation

BACKGROUND

This study assessed the effect of postprandial glucose reduction by acarbose on insulin sensitivity and biomarkers of systemic inflammation.

METHODS

This was a single-center, double-blind, randomized, placebo-controlled, crossover study <40 weeks in duration, involving 66 subjects with varying degrees of glucose tolerance. Eligible patients completed a 3-week run-in period and were randomized to receive either 100 mg of acarbose three times daily followed by placebo, or vice versa, lasting 12 weeks each with a 12-week washout between interventions. Liquid meal challenges and hyperinsulinemic-euglycemic glucose clamp were performed at weeks 0, 12, 24, and 36.

RESULTS

Fasting proinsulin levels and proinsulin-to-adiponectin ratios but not fasting adiponectin levels were significantly lower during acarbose versus placebo treatment. Clamp-derived insulin sensitivity index and body weight were unchanged by the intervention. Levels of fasting insulin, fasting glucose, monocyte chemoattractant protein-1, interleukin-6, and interleukin-1β were comparable between treatments. In the liquid meal challenge tests, postprandial glucose and insulin responses were significantly lower during acarbose versus placebo treatment. The effects of acarbose on the reduction of fasting proinsulin was most pronounced in subjects with impaired fasting glucose/impaired glucose tolerance (n = 24).

CONCLUSIONS

Reduction of the glycemic load by acarbose decreased fasting levels of proinsulin but had no effect on adiponectin and whole-body insulin sensitivity as well as biomarkers reflecting inflammation. The preventive effects of acarbose on type 2 diabetes mellitus and cardiovascular risk need further investigation and cannot be explained by changes of insulin resistance and inflammatory biomarkers.