Factors determining normalization of glucose intolerance in middle-aged Swedish men and women: a 8-10-year follow-up

Failure to decrease HbA1c levels following TB treatment is associated with elevated Th1/Th17 CD4+ responses

Introduction

The rising global burden of metabolic disease impacts the control of endemic tuberculosis (TB) in many regions, as persons with diabetes mellitus (DM) are up to three times more likely to develop active TB than those without DM. Active TB can also promote glucose intolerance during both acute infection and over a longer term, potentially driven by aspects of the immune response. Identifying patients likely to have persistent hyperglycemia following TB treatment would enable closer monitoring and care, and an improved understanding of underlying immunometabolic dysregulation.

Methods

We measured the relationship of plasma cytokine levels, T cell phenotypes and functional responses with the change in hemoglobin A1c (HbA1c) before and after treatment of pulmonary TB in a prospective observational cohort in Durban, South Africa. Participants were stratified based on stable/increased HbA1c (n = 16) versus decreased HbA1c (n = 46) levels from treatment initiation to 12 month follow-up.

Results

CD62 P-selectin was up- (1.5-fold) and IL-10 downregulated (0.85-fold) in plasma among individuals whose HbA1c remained stable/increased during TB treatment. This was accompanied by increased pro-inflammatory TB-specific IL-17 production (Th17). In addition, Th1 responses were upregulated in this group, including TNF-α production and CX3CR1 expression, with decreased IL-4 and IL-13 production. Finally, the TNF-α+ IFNγ+ CD8+ T cells were associated with stable/increased HbA1c. These changes were all significantly different in the stable/increased HbA1c relative to the decreased HbA1c group.

Discussion

Overall, these data suggest that patients with stable/increased HbA1c had an increased pro-inflammatory state. Persistent inflammation and elevated T cell activity in individuals with unresolved dysglycemia following TB treatment may indicate failure to fully resolve infection or may promote persistent dysglycemia in these individuals, and further studies are needed to explore potential mechanisms.

Are the determinants of the progression to type 2 diabetes and regression to normoglycemia in the populations with pre-diabetes the same?

BACKGROUND

We aimed to determine the predictors of regression to normoglycemia and progression to diabetes among subjects with pre-diabetes in a single model concurrently.

METHODS

The present study included 1329 participants aged 20 to 70 years with prediabetes from the population-based cohort of the Tehran Lipid and Glucose Study, with a 10-year follow-up. Glycemic status at follow-up was categorized as regression to normoglycemia: fasting plasma glucose [FPG] of <5.55 and 2h-plasma glucose [PG] of <7.77 mmol/L, and not taking antidiabetic medications. Glycemic status at follow-up was categorized as progression to diabetes: FPG ≥7 or 2h-PG of ≥11.1 mmol/L, or taking antidiabetic medications. Glycemic status determined whether the patients remained in prediabetes category (isolated impaired fasting glycaemia [iIFG] [(5.55≤FPG<7 and 2h-PG<7.77 mmol/L); isolated impared glucose tolarence [iIGT] (7.77 ≤ 2h-PG<11.1 and FGP<5.55 mmol/L)]. With prediabetes as a reference, multinomial logistic regression was utilized to identify the determinants of glycemic changes.

RESULTS

Approximately 40% of participants returned to normoglycemia (n = 578), and similar percentage of participants progressed to diabetes (n = 518). Based on the multivariable multinomial model, regression to normoglycemia was associated with age (relative risk ratio [RRR] = 0.97; 95% CI, 0.95-0.99), female sex (RRR = 1.72; 95% CI, 1.18-2.50), high education level of ≥12 years (RRR = 2.10; 95% CI, 1.19-3.70), and combined IFG/impaired glucose tolerance (IGT) versus IFG (RRR = 0.45; 95% CI, 0.29-0.70). The risk of progression to diabetes increased with body mass index (RRR = 1.10; 95% CI, 1.05-1.15), waist circumference (RRR = 0.97; 95% CI, 0.96-0.99), positive familial history of diabetes (RRR = 1.62; 95% CI, 1.07-2.45), and combined IFG/IGT versus IFG (RRR = 2.54; 95% CI, 1.71-3.77).

CONCLUSION

A small percentage of patients with prediabetes remain in this condition, but the majority go on to develop diabetes or regress to normoglycemia. Both directions had distinct predictors.

Intervention Fidelity Focusing on Interaction between Participants and Facilitators in a Telephone-Delivered Health Coaching Intervention for the Prevention and Management of Type 2 Diabetes

Self-management support and lifestyle interventions with an empowerment approach have been found to be effective strategies for health improvement among people at risk for or living with type 2 diabetes. Telephone coaching seems particularly efficient for individuals with low socioeconomic status and culturally and linguistically diverse backgrounds. In this mixed methods study, we investigate a telephone-delivered health coaching intervention provided by the diabetes project SMART2D (Self-Management Approach and Reciprocal learning for Type 2 Diabetes) implemented in socioeconomically disadvantaged areas in Stockholm, Sweden. We focus on the interaction between participants and facilitators as part of intervention fidelity. Recorded coaching sessions were scored using an interaction tool and analyzed by exploratory factor analysis and recorded supervisory discussions with facilitators analyzed using thematic analysis. The quantitative analysis showed that the intervention components were delivered as intended; however, differences between facilitators were found. The qualitative data highlighted differences between facilitators in the delivery, especially in relation to dietary and physical activity goalsetting. The level of language skills hindered the delivery flow and the tailoring of sessions to participants’ needs led to different delivery styles. The interaction between facilitators and participants is an important aspect of intervention implementation. Tailoring of interventions is necessary, and language-skilled facilitators are needed to minimize barriers in intervention delivery.

Profiles of Glucose Metabolism in Different Prediabetes Phenotypes, Classified by Fasting Glycemia, 2-Hour OGTT, Glycated Hemoglobin, and 1-Hour OGTT: An IMI DIRECT Study

Differences in glucose metabolism among categories of prediabetes have not been systematically investigated. In this longitudinal study, participants (N = 2,111) underwent a 2-h 75-g oral glucose tolerance test (OGTT) at baseline and 48 months. HbA_1c was also measured. We classified participants as having isolated prediabetes defect (impaired fasting glucose [IFG], impaired glucose tolerance [IGT], or HbA_1c indicative of prediabetes [IA1c]), two defects (IFG+IGT, IFG+IA1c, or IGT+IA1c), or all defects (IFG+IGT+IA1c). β-Cell function (BCF) and insulin sensitivity were assessed from OGTT. At baseline, in pooling of participants with isolated defects, they showed impairment in both BCF and insulin sensitivity compared with healthy control subjects. Pooled groups with two or three defects showed progressive further deterioration. Among groups with isolated defect, those with IGT showed lower insulin sensitivity, insulin secretion at reference glucose (ISR_r), and insulin secretion potentiation (P < 0.002). Conversely, those with IA1c showed higher insulin sensitivity and ISR_r (P < 0.0001). Among groups with two defects, we similarly found differences in both BCF and insulin sensitivity. At 48 months, we found higher type 2 diabetes incidence for progressively increasing number of prediabetes defects (odds ratio >2, P < 0.008). In conclusion, the prediabetes groups showed differences in type/degree of glucometabolic impairment. Compared with the pooled group with isolated defects, those with double or triple defect showed progressive differences in diabetes incidence.

Machine learning for prediction of diabetes risk in middle-aged Swedish people

Aims

To study if machine learning methodology can be used to detect persons with increased type 2 diabetes or prediabetes risk among people without known abnormal glucose regulation.

Methods

Machine learning and interpretable machine learning models were applied on research data from Stockholm Diabetes Preventive Program, including more than 8000 people initially with normal glucose tolerance or prediabetes to determine high and low risk features for further impairment in glucose tolerance at follow-up 10 and 20 years later.

Results

The features with the highest importance on the outcome were body mass index, waist-hip ratio, age, systolic and diastolic blood pressure, and diabetes heredity. High values of these features as well as diabetes heredity conferred increased risk of type 2 diabetes. . The machine learning model was used to generate individual, comprehensible risk profiles, where the diabetes risk was obtained for each person in the data set. Features with the largest increasing or decreasing effects on the risk were determined.

Conclusions

The primary application of this machine learning model is to predict individual type 2 diabetes risk in people without diagnosed diabetes, and to which features the risk relates. However, since most features affecting diabetes risk also play a role for metabolic control in diabetes, e.g. body mass index, diet composition, tobacco use, and stress, the tool can possibly also be used in diabetes care to develop more individualized, easily accessible health care plans to be utilized when encountering the patients.

The heterogeneity of reversion to normoglycemia according to prediabetes type is not explained by lifestyle factors

Healthy lifestyle interventions and drug therapies are proven to have a positive preventative influence on normal glucose regulation in prediabetes. However, little is known on the specific role that these factors play on reversion to normal glycemia according to type of prediabetes. We used data from the Observational prospective cohort study, The Cohort study in Primary Health Care on the Evolution of Patients with Prediabetes from 2012 to 2015. A total of 1184 individuals aged 30-74 years old were included and classified based on the ADA in three mutually exclusive groups using either fasting plasma glucose (FPG) levels (from 100 to 125 mg/dl, FPG group), HbA_1c (5.7-6.4%, HbA1c group) or both impaired parameters. Information on lifestyle factors and biochemical parameters were collected at baseline. Reversion to normal glucose regulation was calculated at third year of follow-up. Relationship of lifestyle factor and type of prediabetes with reversion were estimated using odds ratios (ORs) with 95% confidence intervals (95% CIs) adjusting by different groups of confounders. Proportion of reversion rates were 31% for FPG group, 31% for HbA1c group and 7.9% for both altered parameters group, respectively. Optimal life style factors such as BMI < 25 kg/m²[OR (95% CI): 1.90 (1.20-3.01)], high adherence to Mediterranean diet 1.78 (1.21-2.63) and absence of abdominal obesity 1.70 (1.19-2.43) were the strongest predictors for reversion to normal glucose. However, those did not modify the ORs of reversion to normal glucose. Taking as reference those with both impaired parameters, subjects with FPG impairment (FPG group) had an OR of 4.87 (3.10-7.65) and 3.72 (2.39-5.78) for HbA1c group. These estimates remained almost the same after further adjustment for biochemical parameters and lifestyle factors (4.55(2.84-7.28) and 3.09 (1.92-4.97), respectively). Optimal lifestyle factors showed to be a positive predictor for reversion to normal glucose regulation however, the differences of reversion risk according type of prediabetes are not explained by lifestyle factors.

Reversion from prediabetes to normoglycaemia after weight change in older persons: The KORA F4/FF4 study

BACKGROUND AND AIMS

In a non-interventional study of older persons, we assessed the impact of changes in BMI and waist circumference (WC) on reversion from glucose- and HbA1c-defined prediabetes to normoglycaemia (in short: reversion) and on persistence of normoglycaemia. Moreover, we studied whether reversion reduced cardiovascular risk.

METHODS AND RESULTS

From the population-based KORA S4/F4/FF4 cohort study conducted in Southern Germany, we utilized data from the second and third visit to the study center (median follow-up 6.5 years). We used two overlapping data sets, one with 563 persons with HbA1c<6.5% (mean age 69 years, 51.5% men), one with 510 persons with glucose-based prediabetes or normal glucose tolerance. We calculated proportions of reversion, and estimated adjusted relative risks for the association between initial BMI/WC and change of BMI/WC, respectively, and reversion (and persistence of normoglycaemia, respectively). We estimated 10-year cardiovascular risks using the Framingham 2008 score. Overall, 27.3% of persons with HbA1c-defined prediabetes and 9.2% of persons with glucose-based prediabetes returned to normoglycaemia during follow-up. Lower initial BMI/WC and reduction of BMI/WC were associated with larger probabilities of returning to normoglycaemia (e.g., for HbA1c 5.7-6.4%, RR = 1.24 (95% CI: 1.09-1.41) per 1 kg/m² decline of BMI). Moreover, reduction of BMI/WC increased probabilities of maintaining normoglycaemia (e.g., for glucose-based prediabetes, RR = 1.09 (1.02-1.16) per 1 kg/m² decline of BMI). 10-year cardiovascular risk was 5.6 (1.7-9.6) percentage points lower after reversion from glucose-based prediabetes to normoglycaemia.

CONCLUSION

In older adults, even moderate weight reduction contributes to reversion from prediabetes to normoglycaemia and to maintaining normoglycaemia.

"I Did Not Believe You Could Get Better"-Reversal of Diabetes Risk Through Dietary Changes in Older Persons with Prediabetes in Region Stockholm

Diabetes risk can be controlled and even reversed by making dietary changes. The aim of this study was to improve the understanding of how older persons with a high risk of developing Type 2 diabetes manage and relate to information about diabetes risk over a ten-year period. Fifteen qualitative interviews were conducted among participants from the Stockholm Diabetes Prevention Program (SDPP). The participants were asked to recall the health examinations conducted by the SDPP related to their prediabetes and to describe their experiences and potential changes related to diet and physical activity. Data were analyzed using qualitative content analysis. The main theme found was that T2D (type 2 diabetes) risk is not perceived as concrete enough to motivate lifestyle modifications, such as changing dietary patterns, without other external triggers. Diagnosis was recognized as a reason to modify diet, and social interactions were found to be important for managing behavior change. Diagnosis was also a contributing factor to lifestyle modification, while prognosis of risk was not associated with efforts to change habits. The results from this study suggest that the potential of reversing prediabetes needs to be highlighted and more clearly defined for older persons to serve as motivators for lifestyle modification.

Natural history of prediabetes in older adults from a population-based longitudinal study

BACKGROUND

The natural history of prediabetes in older adults remains unknown.

OBJECTIVES

To assess the rate at which prediabetes progresses to diabetes, leads to death or reverts to normoglycaemia in older adults and to identify prognostic factors related to different outcomes of prediabetes.

METHODS

In the Swedish National Study on Aging and Care-Kungsholmen, 2575 diabetes-free participants aged ≥60 years were examined at baseline and followed for up to 12 years. At each wave, diabetes was diagnosed via medical examination, antidiabetic drug use, medical records or glycated haemoglobin (HbA1c) ≥6.5%. Prediabetes was defined as HbA1c ≥5.7% and normoglycaemia as HbA1c <5.7% in diabetes-free participants. Data were analysed with multinomial logistic regression.

RESULTS

At baseline, 918 (36%) individuals had prediabetes. Of them, 204 (22%) reverted to normoglycaemia (3.4/100 person-years, 95% CI 5.6-12.3), 119 (13%) developed diabetes (2.0/100 person-years, 95% CI 1.7-2.4) and 215 (23%) died (13.0/100 person-years, 95% CI 11.4-14.9) during the 12-year follow-up. The rates of reversion, progression and mortality were higher in the first 6-year than in the second 6-year follow-up, albeit not statistically significant. Lower systolic blood pressure (SBP), absence of heart diseases and weight loss promoted the reversion from prediabetes to normoglycaemia, whilst obesity accelerated its progression to diabetes.

CONCLUSIONS

During a 12-year follow-up, most of older adults with prediabetes remained stable or reverted to normoglycaemia, whereas only one-third developed diabetes or died. Lower SBP, no heart diseases and weight management may promote reversion to normoglycaemia, suggesting possible strategies for achieving normoglycaemia in older adults with prediabetes.

Different Contributions of Dyslipidemia and Obesity to the Natural History of Type 2 Diabetes: 3-Year Cohort Study in China

AIM

It is known that different stages of type 2 diabetes represent distinct pathophysiological changes, but how the spectrum of risk factors varies at different stages is not yet clarified. Hence, the aim of this study was to compare the effect of different metabolic variables on the natural history of type 2 diabetes.

METHODS

A total of 5,213 nondiabetic (normal glucose tolerance (NGT) and prediabetes) Chinese older than 40 years participated this prospective cohort study, and 4,577 completed the 3-year follow-up. Glycemic status was determined by standard oral glucose tolerance test both at enrollment and follow-up visit. Predictors for conversion in glycemic status were studied in a corresponding subcohort using the multiple logistic regression analysis.

RESULTS

The incidence of prediabetes and diabetes of the cohort was 93.6 and 42.2 per 1,000 person-years, respectively. After a 3-year follow-up, 33.1% of prediabetes patients regressed to NGT. The predictive weight of body mass index (BMI), serum triglyceride, total cholesterol, and systolic blood pressure in different paths of conversions among diabetes, prediabetes, and NGT differed. Specifically, BMI was the strongest predictor for regression from prediabetes to NGT, while triglyceride was most prominent for onset of diabetes. One SD increase in serum triglyceride was associated with a 1.29- (95% CI 1.10-1.52; P = 0.002) or 1.12- (95% CI 1.01-1.27; P = 0.039) fold higher risk of diabetes for individuals with NGT or prediabetes, respectively.

CONCLUSION

Risk factors for different stages of diabetes differed, suggesting personalized preventive strategies for individuals with different basal glycemic statuses.

Factors associated with regression from prediabetes to normal glucose tolerance in a Korean general population: A community-based 10-year prospective cohort study

AIM

A proportion of people with prediabetes convert back to normal glucose tolerance. We sought to determine the clinical variables associated with conversion from prediabetes to normal glucose tolerance, with a focus on insulin secretory capacity, insulin sensitivity and body composition.

METHODS

We followed 1731 people with prediabetes at baseline from the Korean Genome and Epidemiology Study every 2 years for 10 years. Oral glucose tolerance tests (OGTT) were performed, and muscle and fat mass were estimated using bioelectrical impedance analysis.

RESULTS

During 10 years of follow-up, 36% (623/1731) of people with prediabetes converted to normal glucose tolerance. Higher baseline fasting glucose, 2-h OGTT glucose and triglyceride levels were inversely associated with this conversion. Higher 60-min insulinogenic index (IGI₆₀ ) at baseline was independently associated with this conversion [HR per sd (95% CI) 1.09 (1.02-1.17); P = 0.01]. However, other indices reflecting insulin sensitivity, including the composite insulin sensitivity index, were not associated with this conversion. In addition, a higher baseline muscle to fat ratio was independently associated with conversion to normal glucose tolerance [HR per sd (95% CI) 1.15 (1.04-1.26); P = 0.005]. People with conversion to normal glucose tolerance showed a greater increase in the 60-min insulinogenic index and disposition index and a smaller decrease in the composite insulin sensitivity index compared with people without conversion during 10 years of follow-up (all p-values < 0.001).

CONCLUSION

A higher insulin secretory capacity at baseline and during follow-up and higher baseline muscle to fat ratio were independently associated with an improvement in glucose tolerance in Korean adults with prediabetes.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG_5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG_6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c_5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c_6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG_5.6, IFG_6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG_6.1 and IFG_5.6. Limited data showed a higher T2DM incidence associated with HbA1c_6.0 compared to HbA1c_5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG_5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG_6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c_5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c_6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Diabetes diagnostic thresholds of the glycated hemoglobin A1c and fasting plasma glucose levels considering the 5-year incidence of retinopathy

AIMS

As retinopathy is used as a defining threshold of diabetes, we assessed the glycated hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) values associated with an increased risk of 5-year incidence of retinopathy.

METHODS

We studied HbA1c, FPG, and optic fundus findings of 2605 individuals without previously diagnosed diabetes annually during a 5-year period. Retinopathy was examined using non-mydriatic, 45° digital fundus photography. Baseline levels were stratified as <5.3 [34], 5.3-5.6 [34-38], 5.7-6.0 [39-42], 6.1-6.4 [43-47], and ⩾6.5% [48mmol/mol] for HbA1c and <5.0, 5.0-5.5, 5.6-6.0, 6.1-6.9, and ⩾7.0mmol/L for FPG. Cox proportional hazard models were used to analyze hazard ratios (HRs) associated with HbA1c or FPG for incident retinopathy.

RESULTS

During a total of 11845 person-years, we identified 50 (1.9%) cases of incident retinopathy. The adjusted HRs for incident retinopathy associated with a one-standard deviation increase in HbA1c and FPG were 1.2 (95% confidence intervals: 1.1-1.4) and 1.2 (1.1-1.4), respectively. These HRs were significantly higher for a HbA1c level ⩾6.5% (48mmol/mol) (3.4 [1.1-10.2]) or FPG level ⩾7.0mmol/L (3.6 [1.1-11.6]) than for a HbA1c level <5.3% (34mmol/mol) or FPG level <5.0mmol/L.

CONCLUSIONS

A HbA1c value of 6.5% (48mmol/mol) and FPG value of 7.0mmol/L might be proper as diabetes diagnostic thresholds that indicate a high risk of future retinopathy.

Long-term aircraft noise exposure and body mass index, waist circumference, and type 2 diabetes: a prospective study

BACKGROUND

Long-term aircraft noise exposure may increase the risk of cardiovascular disease, but no study has investigated chronic effects on the metabolic system.

OBJECTIVES

The aim of this study was to investigate effects of long-term aircraft noise exposure on body mass index (BMI), waist circumference, and type 2 diabetes. Furthermore, we explored the modifying effects of sleep disturbance.

METHODS

This prospective cohort study of residents of Stockholm County, Sweden, followed 5,156 participants with normal baseline oral glucose tolerance tests (OGTT) for up to 10 years. Exposure to aircraft noise was estimated based on residential history. Information on outcomes and confounders was obtained from baseline and follow-up surveys and examinations, and participants who developed prediabetes or type 2 diabetes were identified by self-reported physician diagnosis or OGTT at follow-up. Adjusted associations were assessed by linear, logistic, and random-effects models.

RESULTS

The mean (± SD) increases in BMI and waist circumference during follow-up were 1.09 ± 1.97 kg/m2 and 4.39 ± 6.39 cm, respectively. The cumulative incidence of prediabetes and type 2 diabetes was 8% and 3%, respectively. Based on an ordinal noise variable, a 5-dB(A) increase in aircraft noise was associated with a greater increase in waist circumference of 1.51 cm (95% CI: 1.13, 1.89), fully adjusted. This association appeared particularly strong among those who did not change their home address during the study period, which may be a result of lower exposure misclassification. However, no clear associations were found for BMI or type 2 diabetes. Furthermore, sleep disturbances did not appear to modify the associations with aircraft noise.

CONCLUSIONS

Long-term aircraft noise exposure may be linked to metabolic outcomes, in particular increased waist circumference.

Psychotic disorder is an independent risk factor for increased fasting glucose and waist circumference

BACKGROUND

Psychosis is associated with excess cardiovascular morbidity and mortality.

AIMS

To determine the prevalence of cardiovascular risk factors in patients with psychotic disorders compared with the population.

METHODS

731 consecutive patients with psychosis recruited from psychiatric outpatient clinics in Stockholm County, Sweden, were compared with 5580 individuals from a population study performed in the same area. The main outcome measures were waist circumference, body mass index (BMI) and fasting glucose.

RESULTS

Mean waist circumference in patients vs. controls was for males 106 and 94 cm, respectively, and for females 97 and 85 cm, respectively (P < 0.001); mean fasting glucose in patients vs. controls was for males 5.8 and 5.2 mmol/l, respectively, and for females 5.6 and 4.8 mmol/l, respectively (P < 0.001). Comparisons were controlled for differences in age and family history of diabetes. Increased waist circumference was more common in psychotic patients compared with controls (OR = 3.99; 95% CI 3.09-5.15), controlling for fasting insulin, differences in gender, blood pressure, fasting glucose, family history of diabetes, age and tobacco use. Increased fasting blood glucose was also more common in psychotic patients (OR = 2.41; 95% CI 1.84-3.14) controlling for the same factors with the exception of fasting glucose and with the addition of increased waist circumference.

CONCLUSION

Our study shows that the psychosis illness per se can be considered as a cardiovascular risk factor, independent of the traditional risk factors such as age and smoking.

Risk equations for the development of worsened glucose status and type 2 diabetes mellitus in a Swedish intervention program

Background

Several studies investigated transitions and risk factors from impaired glucose tolerance (IGT) to type 2 diabetes mellitus (T2D). However, there is a lack of information on the probabilities to transit from normal glucose tolerance (NGT) to different pre-diabetic states and from these states to T2D. The objective of our study is to estimate these risk equations and to quantify the influence of single or combined risk factors on these transition probabilities.

Methods

Individuals who participated in the VIP program twice, having the first examination at ages 30, 40 or 50 years of age between 1990 and 1999 and the second examination 10 years later were included in the analysis. Participants were grouped into five groups: NGT, impaired fasting glucose (IFG), IGT, IFG&IGT or T2D. Fourteen potential risk factors for the development of a worse glucose state (pre-diabetes or T2D) were investigated: sex, age, education, perceived health, triglyceride, blood pressure, BMI, smoking, physical activity, snus, alcohol, nutrition and family history. Analysis was conducted in two steps. Firstly, factor analysis was used to find candidate variables; and secondly, logistic regression was employed to quantify the influence of the candidate variables. Bootstrap estimations validated the models.

Results

In total, 29 937 individuals were included in the analysis. Alcohol and perceived health were excluded due to the results of the factor analysis and the logistic regression respectively. Six risk equations indicating different impacts of different risk factors on the transition to a worse glucose state were estimated and validated. The impact of each risk factor depended on the starting or ending pre-diabetes state. High levels of triglyceride, hypertension and high BMI were the strongest risk factors to transit to a worsened glucose state.

Conclusions

The equations could be used to identify individuals with increased risk to develop any of the three pre-diabetic states or T2D and to adapt prevention strategies.

Consumption of whole grain reduces risk of deteriorating glucose tolerance, including progression to prediabetes

BACKGROUND

High whole-grain intake has been reportedly associated with reduced risk of developing type 2 diabetes (T2D), which is an effect possibly subject to genetic effect modification. Confirmation in prospective studies and investigations on the impact on prediabetes is needed.

OBJECTIVES

In a prospective population-based study, we investigated whether a higher intake of whole grain protects against the development of prediabetes and T2D and tested for modulation by polymorphisms of the TCF7L2 gene.

DESIGN

We examined the 8-10-y incidence of prediabetes (impaired glucose tolerance, impaired fasting glucose, or the combination of both) and T2D in relation to the intake of whole grain. Baseline data were available for 3180 women and 2297 men aged 35-56 y.

RESULTS

A higher intake of whole grain (>59.1 compared with <30.6 g/d) was associated with a 34% lower risk to deteriorate in glucose tolerance (to prediabetes or T2D; women and men combined). The association remained after adjustments for age, family history of diabetes, BMI, physical activity, smoking, education, and blood pressure (OR: 0.78; 95% CI: 0.63, 0.96). Risk reduction was significant in men (OR: 0.65; 95% CI: 0.49, 0.85) but not in women. Associations were significant for prediabetes per se (all, OR: 0.73; 95% CI: 0.56, 0.94; men, OR: 0.57; 95% CI: 0.40, 0.80). The intake of whole grain correlated inversely with insulin resistance (HOMA-IR). The impact of whole-grain intake was undetectable in men who harbored diabetogenic polymorphisms of the TCF7L2 gene.

CONCLUSIONS

A higher intake of whole grain is associated with decreased risk of deteriorating glucose tolerance including progression from normal glucose tolerance to prediabetes by mechanisms likely tied to effects on insulin sensitivity. Effect modifications by TCF7L2 genetic polymorphisms are supported.

Coffee consumption and prostate cancer risk: further evidence for inverse relationship

Background

Higher consumption of coffee intake has recently been linked with reduced risk of aggressive prostate cancer (PC) incidence, although meta-analysis of other studies that examine the association between coffee consumption and overall PC risk remains inconclusive. Only one recent study investigated the association between coffee intake and grade-specific incidence of PC, further evidence is required to understand the aetiology of aggressive PCs. Therefore, we conducted a prospective study to examine the relationship between coffee intake and overall as well as grade-specific PC risk.

Methods

We conducted a prospective cohort study of 6017 men who were enrolled in the Collaborative cohort study in the UK between 1970 and 1973 and followed up to 31st December 2007. Cox Proportional Hazards Models were used to evaluate the association between coffee consumption and overall, as well as Gleason grade-specific, PC incidence.

Results

Higher coffee consumption was inversely associated with risk of high grade but not with overall risk of PC. Men consuming 3 or more cups of coffee per day experienced 55% lower risk of high Gleason grade disease compared with non-coffee drinkers in analysis adjusted for age and social class (HR 0.45, 95% CI 0.23-0.90, p value for trend 0.01). This association changed a little after additional adjustment for Body Mass Index, smoking, cholesterol level, systolic blood pressure, tea intake and alcohol consumption.

Conclusion

Coffee consumption reduces the risk of aggressive PC but not the overall risk.

Follow-up of a cardiovascular prevention campaign

The aim of this study was to evaluate the cardiovascular risk (CVR) factors and morbidity in a sample of the population that received a brief intervention on cardiovascular prevention seven years ago. All family physicians who participated in the Cardiovascular Prevention Campaign in five Belgian towns in 2002-2003 received a follow-up questionnaire for each participating patient. The questionnaire included questions about new cardiovascular diagnoses, parameters of the latest physical examination and blood tests. Analyses were based on the 318 questionnaires that included essential information such as the date of the latest contact and the new diagnosis or mortality. The proportion of patients with a low CVR decreased from 75% in 2002-2003 to 40% in 2010. Participants showed a significant increase of the abdominal circumference, triglycerides and fasting glycaemia. Only LDL-cholesterol levels decreased significantly (p = 0.002). Four percent of the patients died, more male (7 ) than female (2%) (p = 0.03). One in ten patients presented with a cardiovascular event. Most of the changes are probably attributable to age. It is clear that the long-term effect of a brief intervention only followed by usual care is not sufficient to attain optimal level of cardiovascular prevention.

Impact of weight and weight change on normalization of prediabetes and on persistence of normal glucose tolerance in an older population: the KORA S4/F4 study

BACKGROUND AND AIMS

In a population-based cohort study with older subjects and without specific interventions, we investigated the impact of body mass index (BMI) and BMI change (as well as waist circumference and change of waist circumference) on reversion from prediabetes to normal glucose tolerance (NGT) and on long-term persistence of NGT.

MATERIALS AND METHODS

Oral glucose tolerance tests were conducted at baseline and at follow-up in a cohort study in Southern Germany (KORA S4/F4; 1223 subjects without diabetes aged 55-74 years at baseline in 1999-2001; 887 subjects (73%), of whom 436 had prediabetes at baseline, participated in the follow-up 7 years later).

RESULTS

BMI reduction, but not initial BMI, predicted reversion from prediabetes to NGT. The odds ratio (OR) for returning to NGT was 1.43 (95% CI: 1.18-1.73) for a BMI decrease of 1 kg m(-2), after adjustment for age, sex, baseline glucose values and lifestyle factors. Initial BMI had no effect on reversion to NGT (OR=0.98, 95% CI: 0.91-1.06, per kg m(-2)). Persistence of NGT was associated with baseline BMI (OR=0.94, 95% CI: 0.88-0.998) and BMI reduction (OR=1.16, 95% CI: 1.02-1.33, per decrease by 1 kg m(-2)). For waist circumference and change of waist circumference similar results were obtained.

CONCLUSION

In older adults, weight loss strongly increased the chances of returning from prediabetes to NGT irrespective of initial BMI. Long-term persistence of NGT depended both on initial BMI and on BMI change.

Natural history and physiological determinants of changes in glucose tolerance in a non-diabetic population: the RISC Study

AIMS/HYPOTHESIS

The natural history and physiological determinants of glucose intolerance in subjects living in Europe have not been investigated. The aim of this study was to increase our understanding of this area.

METHODS

We analysed the data from a population-based cohort of 1,048 non-diabetic, normotensive men and women (aged 30-60 years) in whom insulin sensitivity was measured by the glucose clamp technique (M/I index; average glucose infusion rate/steady-state insulin concentration) and beta cell function was estimated by mathematical modelling of the oral glucose tolerance test at baseline and 3 years later.

RESULTS

Seventy-seven per cent of the participants had normal glucose tolerance (NGT) and 5% were glucose intolerant both at baseline and follow up; glucose tolerance worsened in 13% (progressors) and improved in 6% (regressors). The metabolic phenotype of the latter three groups was similar (higher prevalence of familial diabetes, older age, higher waist-to-hip ratio, higher fasting and 2 h plasma glucose, higher fasting and 2 h plasma insulin, lower insulin sensitivity and reduced beta cell glucose sensitivity with increased absolute insulin secretion). Adjusting for these factors in a logistic model, progression was predicted by insulin resistance (bottom M/I quartile, OR 2.52 [95% CI 1.51-4.21]) and beta cell glucose insensitivity (bottom quartile, OR 2.39 [95% CI 1.6-3.93]) independently of waist-to-hip ratio (OR 1.44 [95% CI 1.13-1.84] for one SD). At follow up, insulin sensitivity and beta cell glucose sensitivity were unchanged in the stable NGT and stable non-NGT groups, worsened in progressors and improved in regressors.

CONCLUSIONS/INTERPRETATION

Glucose tolerance deteriorates over time in young, healthy Europids. Progressors, regressors and glucose-intolerant participants share a common baseline phenotype. Insulin sensitivity and beta cell glucose sensitivity predict and track changes in glucose tolerance independently of sex, age and obesity.

Normalization of glucose intolerance in first-degree relatives of patients with type 2 diabetes

AIMS

The aim of this study was to estimate the conversion rate to normal glucose tolerance (NGT) from a state of abnormal glucose metabolism and to identify characteristics predicting the conversion rate in first-degree relatives (FDRs) of patients with type 2 diabetes with glucose intolerance.

METHODS

A total of 2368 (614 men and 1754 women) FDRs of consecutive patients with type 2 diabetes aged 20-70 years in 2003-2005 were followed through 2007. Glucose tolerance classification was based on the criteria of the American Diabetes Association base on standard 75 g 2-h oral glucose tolerance test. The study group consisted of 370 participants with glucose intolerance at baseline.

RESULTS

The conversion rates to normal glucose tolerance from impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) were 16.2% (95% confidence interval (CI) 13.30, 19.10) and 10.9% (95% CI: 5.7, 16.1) per year after an average of 2 years, respectively. Lower baseline fasting plasma glucose (HR 1.02, 95% CI: 1.01, 1.04) and 2-h (HR 1.02, 95% CI: 1.01, 1.04) glucose predicted conversion to NGT, as did changes in body mass index (BMI), waist circumference (WC), and lipids.

CONCLUSIONS

This is the first estimate of conversion rate and predictors from IFG and IGT to NGT in FDRs of people with type 2 diabetes in Iran. Lower baseline fasting, 2-h plasma glucose and changes in BMI, WC, and lipids predicted reversal to NGT at 24 months follow-up.