The time has come to test the beta cell preserving effects of exercise in patients with new onset type 1 diabetes

Positive Effects of Physical Activity on Insulin Signaling

Physical activity is integral to metabolic health, particularly in addressing insulin resistance and related disorders such as type 2 diabetes mellitus (T2DM). Studies consistently demonstrate a strong association between physical activity levels and insulin sensitivity. Regular exercise interventions were shown to significantly improve glycemic control, highlighting exercise as a recommended therapeutic strategy for reducing insulin resistance. Physical inactivity is closely linked to islet cell insufficiency, exacerbating insulin resistance through various pathways including ER stress, mitochondrial dysfunction, oxidative stress, and inflammation. Conversely, physical training and exercise preserve and restore islet function, enhancing peripheral insulin sensitivity. Exercise interventions stimulate β-cell proliferation through increased circulating levels of growth factors, further emphasizing its role in maintaining pancreatic health and glucose metabolism. Furthermore, sedentary lifestyles contribute to elevated oxidative stress levels and ceramide production, impairing insulin signaling and glucose metabolism. Regular exercise induces anti-inflammatory responses, enhances antioxidant defenses, and promotes mitochondrial function, thereby improving insulin sensitivity and metabolic efficiency. Encouraging individuals to adopt active lifestyles and engage in regular exercise is crucial for preventing and managing insulin resistance and related metabolic disorders, ultimately promoting overall health and well-being.

Global trends in burden of type 2 diabetes attributable to physical inactivity across 204 countries and territories, 1990-2019

Background

To promote a comprehensive understanding of global trends and burden of type 2 diabetes attributable to physical inactivity.

Methods

We utilized data regarding mortality, disability-adjusted life years (DALYs), as well as age-standardized mortality rates (ASMR) and DALYs rates (ASDR) derived from the global burden of disease study 2019 to evaluate the impact of physical inactivity on the prevalence of type 2 diabetes in 204 countries and territories over the period from 1990 to 2019. This method facilitated the analysis of the diabetes burden across different ages, genders, and regions. To determine the long-term progression of type 2 diabetes prevalence, we computed the estimated annual percentage change (EAPC) in burden rates.

Results

Globally, the number of deaths and DALYs from type 2 diabetes due to physical inactivity more than doubled between 1990 and 2019. Concurrently, there was an increase in the ASMR and ASDR, with EAPC of 0.26 (95% CI: 0.13-0.39) and 0.84 (95% CI: 0.78-0.89), respectively. As of 2019, the global ASMR and ASDR for physical inactivity stood at 1.6 (95% UI: 0.8-2.7) per 100 000 and 55.9 (95% UI: 27.2-97.6) per 100 000, respectively. Notable disparities were observed in the type 2 diabetes burden associated with physical inactivity worldwide, with higher sociodemographic index (SDI) countries experiencing lower ASDR and ASMR compared to lower SDI countries. Initially, females exhibited higher ASMR and ASDR than males, but this gender disparity in ASMR and ASDR has lessened in recent years. The mortality and DALYs rates associated with physical inactivity exhibit an inverted V-shaped pattern across various age groups, predominantly affecting the elderly population.

Conclusion

Between 1990 and 2019, there was a marked rise in the worldwide burden of type 2 diabetes associated with physical inactivity, underscoring the role of physical inactivity as a key changeable risk factor in the global landscape of this disease. This necessitates additional research to explore the variables contributing to the varying levels of disease burden across different countries and between sexes. Furthermore, it calls for the formulation of public health policies aimed at guiding prevention tactics, promoting early detection, and enhancing the management of type 2 diabetes.

The association between type 1 diabetes and exercise/physical activity and prolongation of the honeymoon phase in patients

In type 1 diabetes (T1D), pancreatic beta cells are destroyed by the immune system, causing chronic hyperglycemia and micro and macrovascular complications. However, some people experience a 'honeymoon' phase (or partial remission) after being diagnosed with type 1 diabetes. During this phase, a substantial amount of insulin is still produced by the pancreas, helping to reduce blood sugar levels and the requirement for external insulin. The clinical significance of this phase lies in the potential for pharmacological and non-pharmacological interventions during this time frame to either slow down or arrest beta-cell destruction. Clearly, we need to continue researching novel therapies like immunomodulatory agents, but we also need to look at potentially effective therapies with acceptable side effects that can serve as a complement to the medicines currently being studied. Physical activity and exercise, regardless of its type, is one of the factors its impact on the control of diabetes is being investigated and promising results have been achieved. Although there are still limited reports in this regard, there is some evidence to suggest that regular physical exercise could prolong the honeymoon period in both adults and children. In this review, having described the immune base of type 1 diabetes, we outline the benefits of exercise on the general health of individuals with T1D. Moreover, we centered on the honeymoon and current evidence suggesting the effects of physical activity and exercise on this phase duration.

Physical Activity and the Development of Islet Autoimmunity and Type 1 Diabetes in 5- to 15-Year-Old Children Followed in the TEDDY Study

OBJECTIVE

This study investigated physical activity and its association with the development of islet autoimmunity and type 1 diabetes in genetically at-risk children aged 5-15 years.

RESEARCH DESIGN AND METHODS

As part of the longitudinal Environmental Determinants of Diabetes in the Young (TEDDY) study, annual assessment of activity using accelerometry was conducted from age 5 years. Time-to-event analyses using Cox proportional hazard models were used to assess the association between time spent in moderate to vigorous physical activity per day and the appearance of one or several autoantibodies and progression to type 1 diabetes in three risk groups: 1) 3,869 islet autoantibody (IA)-negative children, of whom 157 became single IA positive; 2) 302 single IA-positive children, of whom 73 became multiple IA positive; and 3) 294 multiple IA-positive children, of whom 148 developed type 1 diabetes.

RESULTS

No significant association was found in risk group 1 or risk group 2. A significant association was seen in risk group 3 (hazard ratio 0.920 [95% CI 0.856, 0.988] per 10-min increase; P = 0.021), particularly when glutamate decarboxylase autoantibody was the first autoantibody (hazard ratio 0.883 [95% CI 0.783, 0.996] per 10-min increase; P = 0.043).

CONCLUSIONS

More daily minutes spent in moderate to vigorous physical activity was associated with a reduced risk of progression to type 1 diabetes in children aged 5-15 years who had developed multiple IAs.

Six-Year Complete Remission of Type-1 Diabetes Mellitus in an Adult Treated With Sitagliptin

A "honeymoon" phase is a transient period of type 1 diabetes (T1D) remission, characterized by a significant reduction in insulin requirements and good glycemic control due to a temporary restoration of pancreatic β-cell function. This phenomenon occurs in about 60% of adults with this disease, is usually partial, and lasts for up to 1 year. We present a case of a 6-year complete remission of T1D in a 33-year-old man, the longest remission ever described in the literature to our knowledge. He was referred for presenting a 6-month history of polydipsia, polyuria, and weight loss of 5 kg. Laboratory studies confirmed the diagnosis of T1D (fasting blood glucose of 270 mg/dL; HbA1c of 10.6%, and positive antiglutamic acid decarboxylase), and the patient started intensive insulin therapy. After 3 months, a complete remission of the disease was assumed, he suspended insulin administration and since then, he has been under treatment with sitagliptin 100 mg daily, a low-carbohydrate diet, and regular aerobic physical activity. This work aims to highlight the potential role of these factors in delaying disease progression and preserving pancreatic β-cells when introduced at the time of presentation. More robust, prospective, and randomized studies will be needed to confirm its protective effect on the natural course of the disease and support its indication in adults with newly diagnosed T1D.

Association of HbA1c with VO2max in Individuals with Type 1 Diabetes: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to evaluate the association between glycemic control (HbA1c) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until July 2020. Randomized and observational controlled trials with a minimum number of three participants were included if cardio-pulmonary exercise tests to determine VO2max and HbA1c measurement has been performed. Pooled mean values were estimated for VO2max and HbA1c and weighted Pearson correlation and meta-regression were performed to assess the association between these parameters. We included 187 studies with a total of 3278 individuals with T1DM. The pooled mean HbA1c value was 8.1% (95%CI; 7.9−8.3%), and relative VO2max was 38.5 mL/min/kg (37.3−39.6). The pooled mean VO2max was significantly lower (36.9 vs. 40.7, p = 0.001) in studies reporting a mean HbA1c > 7.5% compared to studies with a mean HbA1c ≤ 7.5%. Weighted Pearson correlation coefficient was r = −0.19 (p < 0.001) between VO2max and HbA1c. Meta-regression adjusted for age and sex showed a significant decrease of −0.94 mL/min/kg in VO2max per HbA1c increase of 1% (p = 0.024). In conclusion, we were able to determine a statistically significant correlation between HbA1c and VO2max in individuals with T1DM. However, as the correlation was only weak, the association of HbA1c and VO2max might not be of clinical relevance in individuals with T1DM.

Association between physical activity before diagnosis and the presence of clinical remission in type 1 diabetes - InlipoDiab1 study

AIM

To investigate whether physical activity is associated with the occurrence of remission in adults with type 1 diabetes.

METHODS

Ninety nine adult participants with newly diagnosed type 1 diabetes were enroled into a prospective, observational study. The participants were advised to exercise 2-3 times a week with moderate intensity for a one-year period. Physical activity was assessed by a self-administrated questionnaire on every fourth visit. We counted the months in which participants fulfiled a partial-remission criteria: HbA1c < 6.5%, C-peptide > 0.5 ng/ml, and daily dose of insulin <0.3 U/kg/day. We assigned the participants to two groups: MORE EFFORT and LESS EFFORT, depending on the median value of physical activity in the studied population.

RESULTS

The occurrence of the remission achieved statistical significance at 6th month with a greater prevalence in MORE EFFORT group (55% vs. 35% p = 0.047). In multivariate logistic regression analysis for the occurrence of remission at 12th month, physical activity before the diagnosis was the only variable that influences the occurrence of the remission (adjusted odds ratios = 3.32 [95% confidence intervals 1.25-8.80]; p = 0.02).

CONCLUSION

In adults with newly diagnosed type 1 diabetes physical activity before the diagnosis is associated with higher occurrence of remission.

Pathophysiology of Physical Inactivity-Dependent Insulin Resistance: A Theoretical Mechanistic Review Emphasizing Clinical Evidence

The modern lifestyle has a negative impact on health. It is usually accompanied by increased stress levels and lower physical activity, which interferes with body homeostasis. Diabetes mellitus is a relatively common metabolic disorder with increasing prevalence globally, associated with various risk factors, including lower physical activity and a sedentary lifestyle. It has been shown that sedentary behavior increases the risk of insulin resistance, but the intermediate molecular mechanisms are not fully understood. In this mechanistic review, we explore the possible interactions between physical inactivity and insulin resistance to help better understand the pathophysiology of physical inactivity-dependent insulin resistance and finding novel interventions against these deleterious pathways.

From Pancreatic β-Cell Gene Networks to Novel Therapies for Type 1 Diabetes

Completion of the Human Genome Project enabled a novel systems- and network-level understanding of biology, but this remains to be applied for understanding the pathogenesis of type 1 diabetes (T1D). We propose that defining the key gene regulatory networks that drive β-cell dysfunction and death in T1D might enable the design of therapies that target the core disease mechanism, namely, the progressive loss of pancreatic β-cells. Indeed, many successful drugs do not directly target individual disease genes but, rather, modulate the consequences of defective steps, targeting proteins located one or two steps downstream. If we transpose this to the T1D situation, it makes sense to target the pathways that modulate the β-cell responses to the immune assault-in relation to signals that may stimulate the immune response (e.g., HLA class I and chemokine overexpression and/or neoantigen expression) or inhibit the invading immune cells (e.g., PDL1 and HLA-E expression)-instead of targeting only the immune system, as it is usually proposed. Here we discuss the importance of a focus on β-cells in T1D, lessons learned from other autoimmune diseases, the "alternative splicing connection," data mining, and drug repurposing to protect β-cells in T1D and then some of the initial candidates under testing for β-cell protection.

Beneficial effects of physical exercise for β-cell maintenance in a type 1 diabetes mellitus animal model

NEW FINDINGS

What is the central question of this study? Type 1 diabetes mellitus (T1D) leads to hyperglycaemia owing to pancreatic β-cell destruction by the immune system. Physical exercise has been shown to have potentially beneficial protective roles against cytokine-induced pancreatic β-cell death, but its benefits are yet to be proved and should be understood better, especially in the islet environment. What is the main finding and its importance? Physical exercise protects against β-cell loss in a well-described animal model for T1D, induced by multiple low doses of streptozotocin. This seems to be related to reduced cytokine-induced β-cell death and increased islet cell proliferation. Contributions of islet neogenesis and/or transdifferentiation of pancreatic non-β-cells into β-cells cannot be excluded.

ABSTRACT

Physical exercise has beneficial effects on pancreatic β-cell function and survival in a pro-inflammatory environment. Although these effects have been linked to decreased islet inflammation and modulation of pro-apoptotic pathways, little is known about the islet microenvironment. Our aim was to evaluate the effects of physical exercise in islet histomorphology in a mouse model of type 1 diabetes mellitus induced by multiple low doses of streptozotocin. As expected, induction of type 1 diabetes mellitus led to β-cell loss and, consequently, decreased islet area. Interestingly, although the decrease in islet area was not prevented by physical exercise, this was not the case for the decrease in β-cell mass. This was probably related to induction of β-cell regeneration, because we observed increased proliferation and regeneration markers, such as Ki67 and Pcna, in islets of trained mice. These were found in the central and peripheral regions of the islets. An increase in the percentage of α- and δ-cells in these conditions, combined with an increase in proliferation and Pax4 labelling in peripheral regions, suggest that β-cell regeneration might also occur by transdifferentiation. This agrees with the presence of cells double stained for insulin and glucagon only in islets of diabetic trained mice. In addition, this group had more extra-islet insulin-positive cells and islets associated with ducts than diabetic mice. Physical exercise also decreased nuclear factor-κB activation in islet cells of diabetic trained compared with diabetic untrained mice, indicating a decrease in pro-inflammatory cytokine-induced β-cell death. Taken together, these findings indicate that preservation of β-cell mass induced by physical exercise involves an increase in β-cell replication and decrease in β-cell death, together with islet neogenesis and islet cell transdifferentiation.

Regular physical activity as a physiological factor contributing to extend partial remission time in children with new onset diabetes mellitus-Two years observation

BACKGROUND

Beneficial effects of physical activity (PA) are confirmed in patients with all types of long-lasting diabetes. The possibility of PA to be a factor prolonging remission phase in children with new-onset type 1 diabetes (T1D) has not yet been thoroughly studied.

OBJECTIVE

The aim of the study was to elucidate the influence of regular PA on prevalence of partial remission (PR), metabolic control, daily insulin requirement (DIR), and C-peptide secretion in children newly diagnosed with T1D.

METHODS

A total of 125 children diagnosed with T1D were studied prospectively for 2 years. Patients were controlled every 3 months and advised with PA according to ISPAD recommendations. Anthropometric parameters, HbA1c, C-peptide level and DIR were analyzed. Patients' PA level was assessed using a self-designed questionnaire.

RESULTS

We classified 43% of participants as physically-active. In this group, lower HbA1c after 2 years, lower DIR after 3, 6 months, and after 2 years (all P < .05) were found. At discharge from hospital, the prevalence of DIR < 0.5 U/kg/24 h with near normoglycemia was similar in both groups. Then, we observed higher PR prevalence in active group lasting over time and resulting in 44% vs 13% after 2 years (P < .001). C-peptide after 2 years was comparable in both groups, with higher prevalence of clinically significant levels (>0.2 nmoL/L) in active group: 79.6% vs 61.4% (P = .029).

CONCLUSIONS

These data support the view that regular PA may essentially contribute to extending PR time in pediatric diabetes, and may therefore lead to a better long-term metabolic control of the disease.

Exercise improves metabolic function and alters the microbiome in rats with gestational diabetes

Gestational diabetes mellitus (GDM) is a common pregnancy complication, particularly prevalent in obese women. Importantly, exercise has beneficial impacts on maternal glucose control and may prevent GDM in "at-risk" women. We aimed to determine whether a high-fat diet (HFD) exacerbates metabolic dysfunction and alters gut microbiome in GDM and whether endurance exercise prevents these changes. Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham (Control) surgery on E18 in Wistar-Kyoto rats. Female offspring were fed a Chow or HFD (23% fat) from weaning (5 weeks) and at 16 weeks randomly allocated to remain Sedentary or to an exercise protocol of either Exercise prior to and during pregnancy (Exercise); or Exercise during pregnancy only (PregEx). Females were mated (20 weeks) and underwent indirect calorimetry (embryonic day 16; E16), glucose tolerance testing (E18), followed by 24-hr feces collection at E19 (n = 8-10/group). HFD consumption in female rats with GDM exacerbated the adverse metabolic adaptations to pregnancy and altered gut microbial populations. Specifically, the Firmicutes-to-Bacteroidetes ratio was increased, due to an underlying change in abundance of the orders Clostridiales and Bacteroidales. Maternal Exercise, but not PregEx, prevented the development of metabolic dysfunction, increased pancreatic β-cell mass, and prevented the alteration of the gut microbiome in GDM females. Our findings suggest that maternal exercise and diet influence metabolic and microbiome dysfunction in females with GDM, which may impact long-term maternal and offspring health.

Exercise and the dipeptidyl-peptidase IV inhibitor sitagliptin do not improve beta-cell function and glucose homeostasis in long-lasting type 1 diabetes-A randomised open-label study

BACKGROUND

Increasing evidence points to beta-cell regeneration in individuals with type 1 diabetes mellitus (type 1 DM) at all stages of the disease. Exercise and glucagon-like peptide-1 (GLP-1) independently improve beta-cell function and glucose homeostasis in animal studies and in clinical trials in individuals with type 2 diabetes mellitus (type 2 DM). Whether a combination of both, exercise and GLP-1, induces a similar effect in individuals with long-lasting type 1 DM remains to be investigated.

METHODS

In an open-label study, participants with long-standing type 1 DM were randomly assigned to oral sitagliptin 100 mg daily for 12 weeks in combination with or without an exercise intervention. The primary end-point was change in the area under the concentration-time curve of C-peptide during a mixed meal tolerance test before and after 12 weeks of intervention.

RESULTS

A total of 24 participants were included in the study and treated with sitagliptin, 12 participants were allocated to a 12-week exercise intervention. After 12 weeks, there was no difference in the change of AUC C-peptide between groups (exercise: 0 [-1424 to 1870], no exercise: 2091 [283-17 434]; P = 0.09). HDL improved in the exercise intervention group compared to the group with sitagliptin only (exercise: 0.11 [-0.09 to 0.27]; no exercise: -0.18 [-0.24 to 0.01]; P = 0.04). AUC glucose was numerically slightly lower in the exercise intervention group but this did not translate into changes in HbA1c.

CONCLUSION

The combination of exercise and sitagliptin had no effect on beta-cell function in individuals with long-lasting type 1 DM.

[Protective effect of vitamin A on residual pancreatic β cell function in children with type 1 diabetes mellitus]

OBJECTIVE

To study the protective effect of vitamin A on residual pancreatic β cell function in children with type 1 diabetes mellitus (T1DM) and its mechanism.

METHODS

A total of 46 children with T1DM (with a course of disease of 0.5-1 year) were randomly divided into an intervention group and a non-intervention group (n=23 each). The children in both groups were given insulin treatment, and those in the intervention group were also given vitamin A at a daily dose of 1 500-2 000 IU. A total of 25 healthy children were enrolled as the control group. The daily dose of insulin was calculated for the children with T1DM, and the serum levels of glycosylated hemoglobin (HbA1C), stimulated C-peptide, vitamin A, and interleukin-17 (IL-17) were measured before intervention and 3 months after intervention.

RESULTS

Before vitamin A intervention, the intervention group and the non-intervention group had a significantly lower serum level of vitamin A and a significantly higher level of IL-17 than the control group (P<0.01). After 3 months of intervention, the intervention group had significantly lower serum IL-17 level and insulin dose and a significantly higher level of stimulated C-peptide than the non-intervention group (P<0.05).

CONCLUSIONS

Vitamin A may protect residual pancreatic β cell function, possibly by improving the abnormal secretion of IL-17 in children with T1DM.

Qualitative study of barriers to clinical trial retention in adults with recently diagnosed type 1 diabetes

OBJECTIVES

Regular physical exercise may preserve β cell function in newly diagnosed adults with type 1 diabetes (T1D). However, clinical trials to test this theory require the recruitment and retention of adults with new-onset T1D, which can be challenging. We sought to determine the overall experiences of newly diagnosed adults with T1D in an exercise study, to understand issues that influence the retention of trial participants in such studies.

DESIGN

Qualitative methodology using individual face-to-face (n=6) and telephone interviews (n=14). Interview transcripts were thematically analysed using the framework method.

SETTING

The study took place at five participating UK hospitals.

PARTICIPANTS

Twenty participants, aged 19-55 years, in the Exercise for Type 1 Diabetes study were interviewed to explore their study experiences and identify motivators and deterrents towards the study. Participants in control and intervention arms were interviewed, as were people with T1D who had completed (n=16) and withdrawn (n=4).

RESULTS

Participants revealed barriers and facilitators to retention; the majority were generalisable to clinical trials of people with newly diagnosed T1D. Coming to terms with a diagnosis of T1D, lack of time, work pressures, level of health professional support, volume, clarity and consistency of information and feedback and a desire for knowledge about their condition were all cited as influencing factors to trial retention.

CONCLUSIONS

To our knowledge, this is the first qualitative study to examine the experience of being involved in an exercise trial by people with T1D. Findings suggest appointments could be shorter, available outside of working hours and planned longer in advance; study information should be clear, consistent and in electronic and paper formats; questionnaires need minimising; healthcare support and feedback needs providing regularly; thought is required around how to support non-exercising arm participants. These considerations may improve participant retention rates in new-onset T1D studies.

Exercise training protects human and rodent β cells against endoplasmic reticulum stress and apoptosis

Prolonged exercise has positive metabolic effects in obese or diabetic individuals. These effects are usually ascribed to improvements in insulin sensitivity. We evaluated whether exercise also generates circulating signals that protect human and rodent β cells against endoplasmic reticulum (ER) stress and apoptosis. For this purpose, we obtained serum from humans or mice before and after an 8 wk training period. Exposure of human islets or mouse or rat β cells to human or rodent sera, respectively, obtained from trained individuals reduced cytokine (IL-1β+IFN-γ)- or chemical ER stressor-induced β-cell ER stress and apoptosis, at least in part via activation of the transcription factor STAT3. These findings indicate that exercise training improves human and rodent β-cell survival under diabetogenic conditions and support lifestyle interventions as a protective approach for both type 1 and 2 diabetes.-Paula, F. M. M., Leite, N. C., Borck, P. C., Freitas-Dias, R., Cnop, M., Chacon-Mikahil, M. P. T., Cavaglieri, C. R., Marchetti, P., Boschero, A. C., Zoppi, C. C., Eizirik, D. L. Exercise training protects human and rodent β cells against endoplasmic reticulum stress and apoptosis.

Beneficial Effects of Aerobic Exercise Training Combined with Rosiglitazone on Glucose Metabolism in Otsuka Long Evans Tokushima Fatty Rats

BACKGROUND

Regular aerobic exercise is essential for the prevention and management of type 2 diabetes mellitus and may be particularly beneficial for those treated with thiazolidinediones, since it may prevent associated weight gain. This study aimed to evaluate the effect of combined exercise and rosiglitazone treatment on body composition and glucose metabolism in obese diabetes-prone animals.

METHODS

We analyzed metabolic parameters, body composition, and islet profiles in Otsuka Long Evans Tokushima Fatty rats after 28 weeks of aerobic exercise, rosiglitazone treatment, and combined exercise and rosiglitazone treatment.

RESULTS

Combined exercise with rosiglitazone showed significantly less increase in weight and epididymal fat compared to rosiglitazone treatment. Aerobic exercise alone and combined rosiglitazone and exercise treatment led to similar retention of lean body mass. All experimental groups showed a decrease in fasting glucose. However, the combined exercise and rosiglitazone therapy group showed prominent improvement in glucose tolerance compared to the other groups. Rescue of islet destruction was observed in all experimental groups, but was most prominent in the combined therapy group.

CONCLUSION

Regular aerobic exercise combined with rosiglitazone treatment can compensate for the adverse effect of rosiglitazone treatment and has benefit for islet preservation.

Exercise to preserve β-cell function in recent-onset Type 1 diabetes mellitus (EXTOD) - a randomized controlled pilot trial

AIM

Residual β-cell function is present at the time of diagnosis with Type 1 diabetes. Preserving this β-cell function reduces complications. We hypothesized that exercise preserves β-cell function in Type 1 diabetes and undertook a pilot trial to address the key uncertainties in designing a definitive trial to test this hypothesis.

METHODS

A randomized controlled pilot trial in adults aged 16-60 years diagnosed with Type 1 diabetes within the previous 3 months was undertaken. Participants were assigned to control (usual care) or intervention (exercise consultation every month), in a 1 : 1 ratio for 12 months. The primary outcomes were recruitment rate, drop out, exercise adherence [weeks with ≥ 150 min of self-reported moderate to vigorous physical activity (MVPA)], and exercise uptake in the control group. The secondary outcomes were differences in insulin sensitivity and rate of loss of β-cell function between intervention and control at 6 and 12 months.

RESULTS

Of 507 individuals who were approached, 58 (28 control, 30 intervention) entered the study and 41 completed it. Participants were largely white European males, BMI 24.8 ± 3.8 kg/m² , HbA_1c 75 ± 25 mmol/mol (9 ± 2%). Mean level of objectively measured MVPA increased in the intervention group (mean 243 to 273 min/week) and 61% of intervention participants reached the target of ≥ 150 min/week of self-reported MVPA on at least 42 weeks of the year. Physical activity levels fell slightly in the control group (mean 277 to 235 min of MVPA/week). There was exploratory evidence that intervention group became more insulin sensitive and required less insulin. However, the rate of loss of β-cell function appeared similar between the groups, although the change in insulin sensitivity may have affected this.

CONCLUSION

We show that it is possible to recruit and randomize people with newly diagnosed Type 1 diabetes to a trial of an exercise intervention, and increase and maintain their exercise levels for 12 months. Future trials need to incorporate measures of greater adherence to exercise training targets, and include more appropriate measures of β-cell function. (Clinical Trials Registry No; ISRCTN91388505).

Effect of 6-months' vitamin D supplementation on residual beta cell function in children with type 1 diabetes: a case control interventional study

BACKGROUND

The aim of this study was to evaluate the effect of short-term vitamin D supplementation on the decline of residual beta cell function (RBCF) in children with type 1 diabetes (T1D).

METHODS

The study involved an intervention group (cholecalciferol 2000 IU/day and calcium 25 mg/kg/day for 6 months) comprising 15 children aged 6-12 years and within 1-2 years of diagnosis of T1D. Fifteen age-matched T1D patients were followed up as controls. Stimulated C-peptide levels were estimated at baseline and 6 months.

RESULTS

The mean decrease in stimulated C-peptide levels in the intervention group was lower (-0.048±0.15 ng/mL) as compared with the controls (-0.107±0.23 ng/mL) but did not reach statistical significance (p=0.472). The percent decrease in stimulated C-peptide from baseline to endpoint (8.3% vs. 20.3%, p=0.357) and the monthly decrease (0.008 ng/mL vs. 0.017 ng/mL, p=0.22) were non-significantly lower in the intervention group compared with the control group. Three (20%) patients progressed to undetectable stimulated C-peptide (≤0.01 ng/mL) over the study period in the control group as compared with one (6%) in the intervention group (p-value 0.260).

CONCLUSIONS

There was a trend towards lesser decline of RBCF with short term cholecalciferol supplementation in children with T1D. Further larger studies are urgently needed to explore the beneficial effects of the relatively inexpensive vitamin D supplementation on RBCF.

Current perspectives on physical activity and exercise for youth with diabetes

Regular physical activity (PA) for youth with diabetes improves cardiorespiratory fitness, body composition, bone health, insulin sensitivity, and psychosocial well-being. However many youth with diabetes or pre-diabetes fail to meet minimum PA guidelines and a large percentage of youth with diabetes are overweight or obese. Active youth with type 1 diabetes tend to have lower HbA1c levels and reduced insulin needs, whereas activity in adolescents at-risk for type 2 diabetes improves various measures of metabolism and body composition. Insulin and nutrient adjustments for exercise in type 1 diabetes is complex because of varied responses to exercise type and because of the different times of day that exercise is performed. This review highlights the benefits of exercise and the established barriers to exercise participation in the pediatric diabetes population. A new exercise management algorithm for insulin and carbohydrate intake strategies for active youth with type 1 diabetes is presented.

Association between cardiorespiratory fitness and the determinants of glycemic control across the entire glucose tolerance continuum

OBJECTIVE

Cardiorespiratory fitness (VO2max) is associated with glycemic control, yet the relationship between VO2max and the underlying determinants of glycemic control is less clear. Our aim was to determine whether VO2max is associated with insulin sensitivity, insulin secretion, and the disposition index, a measure of compensatory pancreatic β-cell insulin secretion relative to insulin sensitivity, in subjects representing the entire range of the glucose tolerance continuum.

RESEARCH DESIGN AND METHODS

A cohort of subjects (N = 313) with heterogeneous age, sex, BMI, and glycemic control underwent measurements of body composition, HbA1c, fasting glucose, oral glucose tolerance (OGTT), and VO2max. OGTT-derived insulin sensitivity (SiOGTT), glucose-stimulated insulin secretion (GSISOGTT), and the disposition index (DIOGTT) (the product of SiOGTT and GSISOGTT) were measured, and associations between VO2max and these determinants of glycemic control were examined.

RESULTS

A low VO2max was associated with high HbA1c (r = -0.33), high fasting glucose (r = -0.34), high 2-h OGTT glucose (r = -0.33), low SiOGTT (r = 0.73), and high early-phase (r = -0.34) and late-phase (r = -0.36) GSISOGTT. Furthermore, a low VO2max was associated with low early- and late-phase DIOGTT (both r = 0.41). Interestingly, relationships between VO2max and either glycemic control or late-phase GSISOGTT deteriorated across the glucose tolerance continuum.

CONCLUSIONS

The association between poor cardiorespiratory fitness and compromised pancreatic β-cell compensation across the entire glucose tolerance continuum provides additional evidence highlighting the importance of fitness in protection against the onset of a fundamental pathophysiological event that leads to type 2 diabetes.