Oxygen (O2) kinetics during early recovery from peak exercise in patients with type 2 diabetes

Aims To examine the oxygen (O₂) kinetics during early recovery from peak exercise in patients with Type 2 diabetes and to examine whether oxygen O₂ recovery is associated with fasting glucose and HbA_1c in this population.

Methods Eighty-nine participants (52 men) aged 51.8 ± 7.1 years (mean ± sd) were divided into three groups: normal weight (BMI ≤ 25.0 kg/m²), overweight/obese without diabetes (BMI ≥ 26 kg/m²) and overweight/obese with Type 2 diabetes. Participants were assessed for their aerobic power (VO_2peak) on a cycle ergometer, provided a fasting blood sample and underwent a series of anthropometric measurements. Early recovery period was measured for 60 s from cessation of exercise and expressed as percentage of VO_2peak (higher percentage represents slower recovery).

Results No significant differences were observed for age between the three study groups. Both the overweight/obese groups without diabetes and with Type 2 diabetes had higher BMI than the normal weight group, with no significant differences between overweight/obese participants without diabetes and those with diabetes. Participants with Type 2 diabetes had lower VO_2peak than overweight/obese participants without diabetes and normal weight individuals (19.6 ± 4.8, 22.6 ± 5.4 and 25.7 ± 5.3 ml kg⁻¹ min⁻¹, respectively, P < 0.004 for overall trends). Participants with Type 2 diabetes also had slower recovery in oxygen O₂ kinetics after exercise, compared with both normal weight and overweight/obese individuals without diabetes (56.5 ± 7.7, 49.2 ± 7.2, 47.7 ± 7.4%, P < 0.004 for overall trends). Multiple regression analysis revealed that percentage of oxygen O₂ recovery was a stronger predictor than VO_2peak, BMI or age for fasting glucose and HbA_1c.

Conclusions Patients with Type 2 diabetes have lower VO_2peak and prolonged oxygen O₂ recovery from peak exercise. However, only prolonged oxygen O₂ recovery was associated with fasting glucose and HbA_1c.

The impact of hypoglycaemia on quality of life and related patient-reported outcomes in Type 2 diabetes : a narrative review

As a common side effect of insulin treatment for diabetes, hypoglycaemia is a constant threat and can have far-reaching and potentially devastating consequences, including immediate physical injury as well as more pervasive cognitive, behavioural and emotional effects. Moreover, as a significant limiting factor in achieving optimal glycaemic control, exposure to hypoglycaemia can influence diabetes self-management.

Although hypoglycaemia is known to occur in Type 2 diabetes, its morbidity and impact on the individual are not well recognized. The aim of the current review is to examine published evidence to achieve a synthesis of the scope and significance of the potential detriment caused by hypoglycaemia to individuals with Type 2 diabetes. The implications of these observations for treatment and research have also been considered.

A narrative review was performed of empirical papers published in English since 1966, reporting the effect of hypoglycaemia on quality of life and related outcomes (including generic and diabetes specificquality of life, emotional well-being and health utilities) in Type 2 diabetes.

Research demonstrates the potential impact of hypoglycaemia on the lives of people with Type 2 diabetes, from an association with depressive symptoms and heightened anxiety, to impairment of the ability to drive, work and function in ways that are important for quality of life. Few studies consider hypoglycaemia as an explanatory variable in combination with quality of life or related primary endpoints. As a consequence, there is a pressing need for high-quality research into the overall impact of hypoglycaemia on the lives of people with Type 2 diabetes.

The impact of hypoglycemia on quality of life in type 2 diabetes : a systematic review.

Hypoglycemia is the commonest and most serious side-effect of insulin treatment for Type 1 diabetes (T1DM). The prevalence of hypoglycemia is lower in insulin-treated Type 2 diabetes (T2DM) than in T1DM but the prevalence increases with duration of insulin therapy and increasingly resembles T1DM. As hypoglycemia has not been widely recognised to affect people with T2DM, its impact on quality of life (QoL) has received little attention.

A systematic literature review was performed to identify empirical papers published in English since 1966 reporting the effect of hypoglycemia on any patient-reported outcomes (PROs), including QoL, in T2DM. Despite our specific interest in QoL, the inclusion criteria were defined broadly to encompass a range of self-assessed psychosocial outcomes, including generic and diabetes-specific QoL, emotional well-being and health utilities. Studies were excluded in which the impact of hypoglycemia was confounded by treatment effects. Our search included: MEDLINE, PsycINFO, CINAHL. Abstracts were screened independently by two investigators.

Of 2,469 abstracts, Thirty-one met the inclusion criteria and were subjected to data extraction and analysis. These comprised four controlled trials and twenty-seven others (including cross-sectional and health utility studies). The results indicate associations between the experience of hypoglycemia and a range of adverse PROs, including impaired QoL and well-being, higher levels of anxiety, depression and anger and loss of health utility. Fear of hypoglycemia was also associated with compensatory lifestyle limitations and changes.

Publications suggest that QoL and other psychosocial outcomes are impaired by the experience and/or fear of hypoglycemia in T2DM, however, very few studies have directly investigated this phenomenon to date. Interpretation of the evidence is hampered by inconsistent or inadequate definitions and measurement of both hypoglycemia and QoL outcomes, by confounding of the impact of hypoglycemia and by treatment factors. Targeted research using appropriate study design is needed to quantify and qualify the true impact of hypoglycemia on QoL in people with T2DM.

Prevalence of vitamin D insufficiency and risk factors for type 2 diabetes and cardiovascular disease among African migrant and refugee adults in Melbourne

Migration to industrialised countries poses a “double whammy” for type 2 diabetes among sub-Saharan African migrant and refugee adults. This population group has been found to be at an increased risk of obesity and type 2 diabetes, which may be further aggravated by inadequate vitamin D status. Thus, this study aimed to describe the demographics of vitamin D insufficiency, obesity, and risk factors for type 2 diabetes among sub-Saharan African migrants and refugees aged 20 years or older living in Melbourne, Australia (n=49). Data were obtained by a questionnaire, medical assessment, and fasting blood samples. The mean serum 25-hydroxyvitamin D level was 27.3 nmol/L (95% CI: 22.2, 32.4 nmol/L); with 25-hydroxyvitamin D levels <50 nmol/L occurring in 88% of participants. Participants displayed a cluster of risk factors for type 2 diabetes and cardiovascular disease: 62% were overweight or obese, 47% had insulin resistance (HOMA-IR ≥2), 25% had low density lipoprotein cholesterol levels ≥3.5 mmol/L, 24.5% had high density lipoprotein cholesterol levels ≤1.03 mmol/L, 34.6% had borderline or high levels of total cholesterol (≥5.2 mmol/L), 18.2% had borderline or high levels of triglyceride (≥1.7 mmol/L), and 16% had hypertension (systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg). These findings suggest that sub-Saharan African migrants and refugees may be at risk of type 2 diabetes and atherosclerosis-related diseases such as ischemic heart disease, stroke, and peripheral vascular disease. Well-designed vitamin D interventions that incorporate lifestyle changes are urgently needed in this sub-population.

Comparison of automated candidate gene prediction systems using genes implicated in type 2 diabetes by genome-wide association studies

Background
Automated candidate gene prediction systems allow geneticists to hone in on disease genes more rapidly by identifying the most probable candidate genes linked to the disease phenotypes under investigation. Here we assessed the ability of eight different candidate gene prediction systems to predict disease genes in intervals previously associated with type 2 diabetes by benchmarking their performance against genes implicated by recent genome-wide association studies.

Results
Using a search space of 9556 genes, all but one of the systems pruned the genome in favour of genes associated with moderate to highly significant SNPs. Of the 11 genes associated with highly significant SNPs identified by the genome-wide association studies, eight were flagged as likely candidates by at least one of the prediction systems. A list of candidates produced by a previous consensus approach did not match any of the genes implicated by 706 moderate to highly significant SNPs flagged by the genome-wide association studies. We prioritized genes associated with medium significance SNPs.

Conclusion
The study appraises the relative success of several candidate gene prediction systems against independent genetic data. Even when confronted with challengingly large intervals, the candidate gene prediction systems can successfully select likely disease genes. Furthermore, they can be used to filter statistically less-well-supported genetic data to select more likely candidates. We suggest consensus approaches fail because they penalize novel predictions made from independent underlying databases. To realize their full potential further work needs to be done on prioritization and annotation of genes.