The impact of family history of diabetes and lifestyle factors on abnormal glucose regulation in middle-aged Swedish men and women

Aims/hypothesis We investigated associations between abnormal glucose regulation and family history of diabetes, separately and in combination with lifestyle risk factors.Subjects and methods This cross-sectional study comprised 3,128 men and 4,821 women, aged 35–56 years, half with a family history of diabetes. Oral glucose tolerance testing identified subjects with previously undiagnosed prediabetes (IFG, IGT) and type 2 diabetes. Information on lifestyle factors was obtained by questionnaire. Biological interaction was measured with the synergy index.Results A family history of diabetes conferred a higher odds ratio (OR) for type 2 diabetes in men (OR=3.1, 95% CI 1.7–5.6) than in women (OR=1.7, 95% CI 1.0–3.0), and the synergy index was 2.8 (95% CI 0.9–9.0), suggesting interaction between a family history of diabetes and sex. For prediabetes and diabetes combined, the synergy index was 1.7 (1.0–2.8). Exposure to only one lifestyle risk factor (obesity, physical inactivity, smoking or low sense of coherence [a psychosocial index]) increased the risk to a similar extent in men and women. Combined exposure to a family history of diabetes and lifestyle-related risk factors had a greater effect on type 2 diabetes than any of these factors alone, especially in men. However, analysis of interaction between a family history of diabetes and the lifestyle factors did not indicate any interaction for diabetes, but did indicate interaction for a family history of diabetes and obesity in women with prediabetes.Conclusions/interpretation Our data suggest a more pronounced effect of a family history of diabetes on the risk of type 2 diabetes in men than in women. While both a family history of diabetes and lifestyle risk factors had effects on type 2 diabetes, irrespective of sex, these effects did not appear to interact.     

Oral contraceptive use and abnormal glucose regulation in Swedish middle aged women

Aim

To investigate the association between oral contraceptive (OC) use and abnormal glucose regulation in Swedish middle aged women.

Methods

A prospective population-based study including 4794 women, aged 36-56 at baseline. None had previously diagnosed diabetes. At both baseline and follow-up 8 years later, the women were examined by oral glucose tolerance test. Information regarding lifestyle factors and anthropometric measurements were collected.

Results

At baseline, current use of OCs was associated with pre (Odds ratio, OR 4.1, 95%CI 2.2-7.8) but not with type 2 diabetes. The association to prediabetes was entirely linked to IGT (OR 7.1, 3.3-15.8) in current users of OCs and in former users (OR 2.1, 1.1-3.9). Women who used OC at baseline had a better cardiovascular disease risk profile; lower body mass index (BMI), more physically active and less smoking. At follow-up, the increased risk did not persist.

Conclusion

Current use of OC was associated with a four times increased risk of having prediabetes and seven times of having impaired glucose tolerance. No increased risk persisted at the follow-up, suggesting that the risk due to prior use of OC is decreasing with time. The healthier lifestyle in women who used OCs may have contributed to reduced long-term risk of prediabetes.     

Report from an effort to prevent type 2 diabetes development in primary care

BackgroundIn a clinical trial 2009–2012, individuals with prediabetes were randomised to a lifestyle intervention (LI) focused on physical activity or care as usual (CAU), with the aim of reducing development of type 2 diabetes (T2DM). At study termination after three years, there was a significantly less of an increase in insulin resistance in LI compared with the CAU group. The aim of this extended follow-up was to investigate whether positive results concerning metabolic variables remained five years after study termination.MethodAll participants from the original study were contacted for a new follow-up with an oral glucose tolerance test, anthropometric measurements, blood pressure and blood samples. Questionnaires about lifestyle were completed.ResultsA total of 69 of the original 123 participants were examined, and personal data for another five participants were collected from the medical charts (n = 74). The LI group showed a decrease in diastolic blood pressure (?4 mmHg, CI 95% 0.8–6.8, p = 0.014) and body weight (?3 kg, CI 95% 1.2–4.9, p = 0.002) since base-line. Weight loss in the LI group was significantly greater compared with weight loss in the CAU group (?3 kg, CI 0.1–5.9, p = 0.044). Insulin resistance markers and incident T2DM were similar among the groups.ConclusionAlthough without modifying the incidence of diabetes or the level of insulin resistance, a physical activity intervention may be used to induce sustainable weight change in subjects with prediabetes at the primary care level.     

Retinol-binding protein 4 is associated with impaired glucose regulation and microalbuminuria in a Chinese population

Aims/hypothesis  Increased retinol-binding protein 4 (RBP4) has been reported in association with insulin resistance and type 2 diabetes. We aimed to investigate the association of serum RBP4 with impaired glucose regulation and microalbuminuria in Chinese adults aged 40 years or older. Methods  Serum RBP4 was measured in 763 individuals with normal glucose regulation, 508 with impaired glucose regulation and 524 newly diagnosed diabetic patients. Serum RBP4 was measured using ELISA and urine albumin/creatinine ratio was used to determine the urinary albumin excretion. Results  Serum RBP4 concentrations were significantly higher in participants with isolated impaired fasting glucose, isolated impaired glucose tolerance, combined impaired fasting glucose/impaired glucose tolerance and diabetes than in those with normal glucose regulation, whereas serum RBP4 levels were not different in the four groups with dysregulation of glucose metabolism. RBP4 was associated with a higher risk for impaired glucose regulation (OR 1.011 for each 1 μg/ml increase in RBP4, 95% CI 1.000–1.022, p = 0.04) after adjustment for sex, age, BMI, current smoking and alcohol intake, family history of diabetes, insulin resistance, triacylglycerol, total cholesterol, and HDL- and LDL-cholesterol; the corresponding OR of combined impaired glucose regulation and type 2 diabetes was 1.022 (95% CI 1.009–1.035, p = 0.0009). RBP4 was associated with the risk of microalbuminuria (OR 1.023, 95% CI 1.004–1.042, p = 0.01) after adjustment for sex, age, smoking habit and alcohol intake, BMI, waist/hip ratio, homeostasis model assessment of insulin resistance, GFR, triacylglycerol, total cholesterol, and HDL- and LDL-cholesterol. Conclusions/interpretation  Serum RBP4 level is closely associated with impaired glucose regulation and is an independent risk factor for microalbuminuria. M. Xu and X. Y. Li contributed equally to this study.     

Plasma glucose levels as predictors of diabetes: the Mexico City diabetes study

Aims/hypothesis  The value of diagnostic categories of glucose intolerance for predicting type 2 diabetes is much debated. We therefore sought to estimate relative and population-attributable risk of different definitions based on fasting (impaired fasting glucose [IFG]) or 2 h plasma glucose concentrations (impaired glucose tolerance [IGT]) and to describe the associated clinical phenotypes. Methods  We prospectively observed a population-based cohort of 1,963 non-diabetic participants (mean age 47 years), in whom an OGTT was performed at baseline and 7 years later. Results  IGT was fivefold more prevalent (13.5%) than IFG. In both categories, participants were older, heavier, hyperinsulinaemic, hyperproinsulinaemic and dyslipidaemic compared with participants with normal glucose tolerance. Relative risk of incident diabetes was similar for IFG and IGT categories (3.73 [95% CI: 2.18–6.39] and 4.01 [95% CI: 3.12–5.14], respectively), but the population-attributable risk was fivefold higher for IGT (29% [95% CI: 26–32]) than for IFG (6% [95% CI: 5–7]). Isolated IFG carried no increase in risk. Lowering the threshold to 5.6 mmol/l raised the population-attributable risk of IFG to 23% (95% CI: 20–25); its contribution to diabetes progression, however, was largely due to co-existent IGT. In multivariate analysis adjusting for sex, age, familial diabetes and BMI, fasting and 2 h glucose were independent predictors. Conclusions/interpretation  Fasting and 2 h glucose values are independent predictors of incident diabetes. Isolated IFG is not a high-risk condition; lowering the diagnostic threshold increases the population-attributable risk of IFG fourfold, but performing an OGTT captures additional diabetes progressors compared with the number identified by IFG.     

Ethnic differences in response to lifestyle intervention for the prevention of type 2 diabetes in adults: A systematic review and meta-analysis

The risk of type 2 diabetes mellitus (T2DM) varies by ethnicity, but ethnic differences in response to diabetes prevention interventions remain unclear. This systematic review and meta-analysis assessed ethnic differences in the effects of lifestyle interventions on T2DM incidence, glycemic outcomes (fasting glucose, 2-h glucose, HbA_1c), anthropometric measures (weight, BMI, waist circumference), and lifestyle behaviors (physical activity, energy intake, energy from fat, fiber intake). MEDLINE, EMBASE, and other databases were searched (to June 15, 2020) for randomized and non-randomized controlled trials on lifestyle interventions (diet and/or physical activity) in adults at risk of T2DM. Ethnicity was categorized into European, South Asian, East and Southeast Asian, Middle Eastern, Latin American, and African groups. Forty-four studies were included in meta-analyses. Overall, lifestyle interventions resulted in significant improvement in T2DM incidence, glycemic outcomes, anthropometric measures, physical activity, and energy intake (all P < 0.01). Significant subgroup differences by ethnicity were found for 2-h glucose, weight, BMI, and waist circumference (all P < 0.05) but not for T2DM incidence, fasting glucose, HbA_1c, and physical activity (all P > 0.05). Few studies in non-European groups reported dietary intake. Lifestyle interventions in different ethnic groups may have similar effects in reducing incidence of T2DM although this needs to be confirmed in further studies.     

No excess 12-year mortality in men with impaired glucose tolerance who participated in the Malmö Preventive Trial with diet and exercise

Summary Impaired glucose tolerance (IGT) is associated with increased mortality due to ischaemic heart disease (IHD), but as it is not known whether this excess mortality can be reduced by preventing or delaying the development of non-insulin-dependent diabetes mellitus (NIDDM), a long-term NIDDM prevention trial of dietary counselling and physical exercise was launched at Malm?, Sweden, the 12-year follow-up of which is reported here. At 12-year follow-up of 6956 men who underwent health screening at 48 years of age, an IGT intervention group (n = 288) who participated in a long-term NIDDM prevention programme were compared with an IGT non-randomised routine treatment group (n = 135), a diabetic group (n = 144), and the remainder, the normal glucose tolerance (NGT) group (n = 6389). The variables studied included the levels of blood glucose, plasma insulin, blood pressure, blood lipids, lung function and maximum oxygen uptake. Subjects with IGT were characterised by overweight, poor vital capacity, hypertension, hypertriglyceridaemia and hyperinsulinaemia. The mortality rate in the IGT intervention group was similar to that in the NGT group (6.5 vs 6.2 per 1000 person years at risk) and lower than that in the IGT routine treatment group (6.5 vs 14.0, p = 0.009). In the two IGT groups taken together, intervention but not body mass index, systolic blood pressure, smoking, cholesterol or the 2-h glucose level predicted mortality. Systolic blood pressure was a predictor of IHD mortality among IGT subjects; and in the cohort as a whole, body mass index, systolic blood pressure, hypercholesterolaemica, diabetes and smoking were predictors of IHD mortality. The findings suggest that a long-term intervention programme, with an emphasis on lifestyle changes, including dietary counselling and physical exercise, will reduce mortality in subjects with IGT who are at an increased risk of both developing NIDDM and of premature death due to IHD and other causes. [Diabetologia (1998) 41: 1010–1016] Received: 20 June 1997 and in revised form: 24 April 1998     

空腹血糖受损、糖耐量受损人群3年自然转归及其影响因素的研究

目的 探讨空腹血糖受损(IFG)、糖耐量受损(IGT)人群发生糖尿病的危险性及其影响因素. 方法对2003年4～6月朝阳市市区居民1 062人糖尿病普查中IFG、IGT患者79人于2006年4～6月进行随访调查.测量身高、体重、腰围、血压,做过夜空腹75g葡萄糖耐量试验,同时测定血总胆固醇(TC),甘油三酯(TG),高密度脂蛋白胆固醇(HDL-C).结果 随访的65人中22人发生糖尿病.其中孤立性IFG(I-IFG)糖尿病转变率为10.8%,孤立性IGT(I-IGT)为9.2%, IFG/IGT为10.4%.在不同的年龄组,随着年龄增长糖代谢异常、高血压、肥胖、脂代谢异常有增加趋势,在40岁以上人群糖代谢异常的患病率有明显增加趋势.进行单因素相关分析结果发现血糖升高可能与增龄、糖尿病(DM)家族史、劳动强度、腰围指数(WC)增加、收缩压(SBP)增加、血脂异常等相关.进行Logistic回归分析,高龄、血压升高、中心性肥胖、体力活动强度减弱均为糖尿病危险因素.结论 I-IGT、IGT/IFG人群糖尿病累计发病率明显高于I-IFG人群.增龄、向心性肥胖、高血压、体力活动减少是糖代谢异常的重要危险因素,因此控制血压、体重,增加体力活动,对糖尿病预防具有重要意义.     

2型糖尿病预防的药物与非药物干预循证医学研究进展

糖耐量减低(IGT)、空腹血糖受损(IFG)是正常糖代谢发展到糖尿病的一个过渡阶段,与糖尿病的发牛密切相关.研究表明,对此类人群给予药物、非药物干预可以明显减少2型糖尿病的发生,具有重要的临床意义.本文就2型糖尿病的药物与非药物干预的相关研究作一综述.     

Approach to the patient with prediabetes

Prediabetes consists of impaired fasting glucose and/or impaired glucose tolerance and is a significant risk factor for the development of type 2 diabetes, microvascular, and macrovascular disease. The values used to define prediabetes are arbitrary, because prediabetes represents an intermediary category along the continuum from normal glucose levels and tolerance to overt hyperglycemia. The progression from prediabetes to type 2 diabetes occurs over many years, strong evidence to support intervention to delay the progression from prediabetes to diabetes. Large, randomized prospective studies with lifestyle intervention and/or various modes of pharmacotherapy have demonstrated successful delay of diabetes. Several issues in the management of prediabetes remain controversial, such as the role of pharmacotherapy and when to escalate treatment. This article will review some of the issues surrounding the identification and treatment of prediabetes, with an interpretation of the available data to help guide management.     

大庆糖尿病前期人群糖耐量改善对心血管事件和死亡率的影响——一项20年随访研究

目的 探讨糖尿病前期人群中改善或减缓糖耐量恶化是否可能降低心血管事件和死亡率.方法 1986年大庆市577例糖耐量受损者被随机分到对照组和3个干预组(饮食、运动和饮食加运动组)进行6年(1986～1992)生活方式干预后又随访14年.本研究将全部受试者按1992年生活干预结束时糖负荷后2 h血糖(2hPG)分为4组(Quartiles,2hPG均值分别为6.17、9.00、12.07和16.96 mmol/L),分析血糖水平高低与随访期间心血管事件及死亡率有无相关.结果 20年随访中共有142例死亡,68例死于心血管疾病(CVD).有首次CVD事件211次(145次脑卒中、66次心梗).从血糖水平最高到血糖最低的4组中全因死亡(17.8、12.7、10.9和9.7/1 0130人年)、CVD死亡(9.1、5.9、6.1和4.9/1 000人年)、CVD事件(30.4、24.0、18.8和19.7/1000人年)和脑卒中(26.6、18.5、16.3和18.1/1 000人年)发生率明显依次递减.多因素分析调整基线年龄、性别、体重指数、血压、吸烟和干预分组的影响后,强化生活方式干预结束时(1992年)2hPG升高5 mmol/L可使全因死亡(HR 1.335,P=0.005)、CVD事件(HR 1.227,P=0.012)和脑卒中(HR1.213.P=0.026)发生率显著升高.结论 在糖尿病前期人群,如果生活干预的强度足以改善或减缓该人群糖耐量的恶化,就可能降低心血管事件和死亡率.     

Determinants of progression from impaired fasting glucose and impaired glucose tolerance to diabetes in a high-risk screened population: 3 year follow-up in the ADDITION study,Denmark

Aims/hypothesis We sought to identify determinants of progression from impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) to diabetes in high-risk screened individuals. Methods In general practices in Denmark, stepwise screening for type 2 diabetes mellitus in persons aged 40 to 69 years included a risk questionnaire, random blood glucose, HbA_1c, fasting blood glucose and an OGTT. The 1,821 individuals with IGT or isolated IFG (WHO 1999) were re-invited after 1 and 3 years. Follow-up data on glucose measurements were available in 1,510 individuals and additional clinical data in 1,002 collected at the 3-year visits. Regression models using interval censoring were used. Results Progression rates from IFG and IGT to diabetes over 3.5 years were 11.8 and 17.0 per 100 person-years, respectively and were particularly high in the first year. Baseline determinants of progression were: IFG: glucose measures, BMI [per kg/m², rate ratio (RR) 1.04 (95% CI, 1.01–1.08)] and triacylglycerol [per twofold increase, RR 2.19 (1.49–3.22)]; and IGT: glucose measures and known hypertension [RR 1.46 (1.11–1.93)]. Weight reduction and decreased triacylglycerol were inversely associated with development of diabetes in IFG individuals [per 1 kg/year, RR 0.81 (0.66–0.98) and per 1 mmol l⁻¹ year⁻¹, RR 0.08 (0.01–0.51), respectively], whereas in IGT participants only weight reduction was inversely associated [per 1 kg/year, RR 0.80 (0.67–0.96)]. Conclusions/interpretation Higher levels of glucose measures, larger BMI, known hypertension and hypertriacylglycerolaemia are significant determinants of progression in high-risk screened individuals. Weight loss of 1 kg/year or reduction of hypertriacylglycerolaemia markedly reduced the risk of diabetes.     

A report on the diagnosis of intermediate hyperglycemia in Korea: A pooled analysis of four community-based cohort studies

Many studies show poor agreement between fasting plasma glucose (FPG)-based and 2-h postchallenge glucose (2-h PG)-based criteria to assess glucose metabolism. We examined the rate of agreement between FPG- and 2-h PG-based criteria in the diagnosis of intermediate hyperglycemia in four representative cohort studies in South Korea and compared the clinical characteristics and biochemical parameters in subjects with impaired fasting glucose (IFG) according to their FPG values.

Of 6234 subjects from four population-based studies performed from 1993 to 2000, 4610 individuals with data from a 75 g oral glucose tolerance test (OGTT) and no previous history of diabetes were selected. We examined the concordance rate between the FPG and 2-h PG-based criteria. We also investigated the differences in the clinical characteristics and biochemical parameters between individuals with IFG according to their FPG values.

The fasting and 2-h PG criteria had large discordance rates in the diagnosis of diabetes and impaired glucose tolerance (IGT) in Korean adults. When individuals with IFG were classified into stage 1 [5.6–6.1 mmol/L (100–109 mg/dL)] and stage 2 [6.1–7.0 mmol/L (110–125 mg/dL)] IFG, individuals with stage 2 IFG are more obese and had higher blood pressure and total cholesterol and triglycerides concentrations compared with those with stage 1 IFG. In addition, more individuals with stage 2 IFG were with diabetes as determined by a 2-h PG ≥ 11.1 mmol/L (14.1% vs. 1.9%) (P < 0.05).

Considering the poorer metabolic profile and higher percentage of people with diabetes by OGTT, these data indicate that, in the Korean population, individuals with stage 2 IFG should be treated differently from those with stage 1 IFG. To detect more cases of diabetes, the OGTT is recommended for all individuals with stage 2 IFG and cases with stage 1 IFG with some additional risk factors for diabetes.     

Improvements in glucose tolerance and insulin sensitivity after lifestyle intervention are related to changes in serum fatty acid profile and desaturase activities: the SLIM study

Aims/hypothesis The aim of this study was to investigate whether lifestyle intervention-induced changes in serum fatty acid profile of cholesteryl esters and estimated desaturase activities are related to improvements in insulin sensitivity in subjects at risk of type 2 diabetes. Materials and methods In the Study on Lifestyle Intervention and Impaired Glucose Tolerance Maastricht (SLIM), 97 men and women with IGT were randomised to a combined diet and exercise programme (47 intervention) or a control group (50 control subjects). At baseline and after 1 year the following assessments were made: an OGTT, an exercise test to determine maximal aerobic capacity, anthropometry, and analysis of the serum fatty acid profile of cholesteryl esters. Results The lifestyle programme was effective in reducing the intake of total and saturated fat, increasing physical activity, reducing obesity and improving insulin sensitivity and glucose tolerance. Regression analysis of the total population showed that an increase in the C20:4 n-6/C20:3 n-6 ratio (estimated Δ5-desaturase activity) and reductions in the C18:3 n-6/C18:2 n-6 ratio (estimated Δ6-desaturase activity) and the C16:1 n-7/C16:0 ratio (estimated Δ9-desaturase activity or stearoyl-CoA desaturase-1) were significantly associated with a decrease in homeostasis model assessment for insulin resistance. After adjustment for lifestyle changes (change in percentage body fat, aerobic capacity and saturated fat intake), these associations were partly reduced, but remained statistically significant. Conclusions/interpretation Lifestyle-induced changes in fatty acid profile of cholesteryl esters and desaturase activities were independently related to changes in insulin sensitivity in subjects at risk of type 2 diabetes.     

Changes in insulin sensitivity in response to different modalities of exercise: a review of the evidence

Type 2 diabetes is an increasingly prevalent condition with complications including blindness and kidney failure. Evidence suggests that type 2 diabetes is associated with a sedentary lifestyle, with physical activity demonstrated to increase glucose uptake and improve glycaemic control. Proposed mechanisms for these effects include the maintenance and improvement of insulin sensitivity via increased glucose transporter type four production. The optimal mode, frequency, intensity and duration of exercise for the improvement of insulin sensitivity are however yet to be identified. We review the evidence from 34 published studies addressing the effects on glycaemic control and insulin sensitivity of aerobic exercise, resistance training and both combined. Effect sizes and confidence intervals are reported for each intervention and meta‐analysis presented. The quality of the evidence is tentatively graded, and recommendations for best practice proposed. © 2013 The Authors. Diabetes/Metabolism Research and Reviews published by John Wiley & Sons, Ltd.     

The Indian Diabetes Prevention Programme shows that lifestyle modification and metformin prevent type 2 diabetes in Asian Indian subjects with impaired glucose tolerance (IDPP-1)

Aims/hypothesis Lifestyle modification helps in the primary prevention of diabetes in multiethnic American, Finnish and Chinese populations. In a prospective community-based study, we tested whether the progression to diabetes could be influenced by interventions in native Asian Indians with IGT who were younger, leaner and more insulin resistant than the above populations. Methods We randomised 531 (421 men 110 women) subjects with IGT (mean age 45.9±5.7 years, BMI 25.8±3.5 kg/m²) into four groups. Group 1 was the control, Group 2 was given advice on lifestyle modification (LSM), Group 3 was treated with metformin (MET) and Group 4 was given LSM plus MET. The primary outcome measure was type 2 diabetes as diagnosed using World Health Organization criteria. Results The median follow-up period was 30 months, and the 3-year cumulative incidences of diabetes were 55.0%, 39.3%, 40.5% and 39.5% in Groups 1–4, respectively. The relative risk reduction was 28.5% with LSM (95% CI 20.5–37.3, p=0.018), 26.4% with MET (95% CI 19.1–35.1, p=0.029) and 28.2% with LSM + MET (95% CI 20.3–37.0, p=0.022), as compared with the control group. The number needed to treat to prevent one incident case of diabetes was 6.4 for LSM, 6.9 for MET and 6.5 for LSM + MET. Conclusions/interpretation Progression of IGT to diabetes is high in native Asian Indians. Both LSM and MET significantly reduced the incidence of diabetes in Asian Indians with IGT; there was no added benefit from combining them. Electronic Supplementary Material Supplementary material is available for this article at     

Design and cohort description of the InterAct Project: an examination of the interaction of genetic and lifestyle factors on the incidence of type 2 diabetes in the EPIC Study

Aims/hypothesis  

Studying gene–lifestyle interaction may help to identify lifestyle factors that modify genetic susceptibility and uncover genetic loci exerting important subgroup effects. Adequately powered studies with prospective, unbiased, standardised assessment of key behavioural factors for gene–lifestyle studies are lacking. This case–cohort study aims to investigate how genetic and potentially modifiable lifestyle and behavioural factors, particularly diet and physical activity, interact in their influence on the risk of developing type 2 diabetes.     

Physical exercise for the prevention and treatment of type 2 diabetes

The prevalence of type 2 diabetes is rapidly increasing worldwide, yet its primary prevention and treatment are still a challenge. The objectives of this review are to assess the effects of exercise on the prevention of type 2 diabetes in high-risk individuals and on glycaemic control in type 2 diabetic patients. Considering the available reports, there is unequivocal and strong evidence that physical exercise can prevent or delay progression to type 2 diabetes in subjects with impaired glucose tolerance. Also, lifestyle interventions, including diet and physical exercise, can result in a reduction of around 50% in diabetes incidence that persists even after the individual lifestyle counselling has stopped. In addition, short-term randomized studies have confirmed that physical training based on endurance and/or resistance exercises can also improve blood glucose control in type 2 diabetics with a mean glycated haemoglobin decrease of 0.6%. Thus, physical exercise should be part of any therapeutic strategy to slow the development of type 2 diabetes in high-risk individuals and to improve glucose control in type 2 diabetes.     

Impaired glucose metabolism and health related quality of life

AimsWe aimed at investigating whether different categories of glucose tolerance have any effect on a person's HRQoL.MethodsPopulation-based cross-sectional study conducted as a community sample of apparently healthy middle-aged individuals living in Western Finland. The subjects of the study, 1383 individuals, aged 45–70 years, had at least one cardiovascular risk factor but no previous diagnoses of either diabetes or cardiovascular disease. They completed health related quality of life (HRQoL) questionnaire before the oral glucose tolerance test (OGTT) was performed to diagnose the gategories of glucose tolerance.ResultsPersons with newly diagnosed type 2 diabetes (NDM) had lower scores for physical functioning, general health and emotional role than subjects with normal glucose tolerance.ConclusionThe results of the HRQoL questionnaire demonstrated that NDM is negatively associated with HRQoL, but prediabetes – IFG or IGT – does not.     

Exercise as a therapeutic intervention for the prevention and treatment of insulin resistance

During the past half-century, there has been a dramatic increase in the incidence of obesity, insulin resistance and type 2 diabetes. A hallmark feature of these conditions is impaired glucose tolerance (IGT). Cross-sectional and retrospective epidemiological studies have provided direct evidence that a lack of physical activity is strongly associated with IGT. Indeed, physical inactivity is an independent risk factor for insulin resistance and type 2 diabetes. The primary defect(s) in the development of whole-body insulin resistance remain unclear. However, during the past decade significant progress has been made towards an understanding of the molecular basis underlying the beneficial effects of exercise training in stimulating the entry of glucose into insulin-sensitive tissues. Accordingly, it is now well accepted that regular physical exercise offers an effective therapeutic intervention to improve insulin action in skeletal muscle in insulin-resistant individuals. This review provides evidence that physical inactivity is significantly associated with IGT and directly contributes to the cascade of events that lead to the expression of the 'exercise-deficient phenotype' associated with insulin resistance and type 2 diabetes. In contrast, exercise training will be shown to significantly reduce the risk of developing insulin resistance by improving glucose tolerance and insulin action in individuals predisposed to develop type 2 diabetes. Several putative mechanisms for enhanced glucose uptake after exercise training will be discussed. A determination of the underlying biological mechanisms that result from exercise training is essential in order to define the precise variations in physical activity that result in the most desired effects on targeted risk factors, and to aid in the development of such interventions.