Reducing Sitting Time in Type 1 Diabetes: Considerations and Implications

Explanatory variables of objectively measured physical activity, sedentary behaviour and sleep in adults with type 1 diabetes: A systematic review

AIMS

This systematic review aimed to summarize knowledge on explanatory variables of PA, SB and sleep in adults with T1D to support the development of healthy lifestyle interventions.

METHODS

A systematic search of four databases (PubMed, Web of Science, Scopus and Embase) was performed. Only objective measurements of PA, SB and sleep were included and all explanatory variables were classified according to the socio-ecological model (i.e. intrapersonal, interpersonal, environmental and policy level). Risk of bias (ROB) (Joanna Briggs Institute appraisal checklists) and level of evidence (Evidence-Based Guideline Development) were assessed.

RESULTS

Twenty-one studies were included (66.7% low ROB). Most explanatory variables were situated at the intrapersonal level. A favourable body composition was associated with more time spent in total PA and moderate-to-vigorous PA (MVPA). Men with T1D spent more time in MVPA than women and a younger age was associated with increased MVPA. Barriers to PA were indeterminately associated with MVPA and HbA1c showed an indeterminate association with sleep. Explanatory variables of SB and light PA were not studied in at least two independent studies.

CONCLUSION

This review underscores the focus on the individual level to identify explanatory variables of movement behaviours in adults with T1D, despite the necessity for a socio-ecological approach to develop effective interventions. More evidence on psychological, interpersonal and environmental variables is needed as these are modifiable.

Insulin Resistance in Type 1 Diabetes: Pathophysiological, Clinical, and Therapeutic Relevance

People with type 1 diabetes (T1D) are usually considered to exclusively exhibit β-cell failure, but they frequently also feature insulin resistance. This review discusses the mechanisms, clinical features, and therapeutic relevance of insulin resistance by focusing mainly on human studies using gold-standard techniques (euglycemic-hyperinsulinemic clamp). In T1D, tissue-specific insulin resistance can develop early and sustain throughout disease progression. The underlying pathophysiology is complex, involving both metabolic- and autoimmune-related factors operating synergistically. Insulin treatment may play an important pathogenic role in predisposing individuals with T1D to insulin resistance. However, the established lifestyle-related risk factors and peripheral insulin administration inducing glucolipotoxicity, hyperinsulinemia, hyperglucagonemia, inflammation, mitochondrial abnormalities, and oxidative stress cannot always fully explain insulin resistance in T1D, suggesting a phenotype distinct from type 2 diabetes. The mutual interaction between insulin resistance and impaired endothelial function further contributes to diabetes-related complications. Insulin resistance should therefore be considered a treatment target in T1D. Aside from lifestyle modifications, continuous subcutaneous insulin infusion can ameliorate insulin resistance and hyperinsulinemia, thereby improving glucose toxicity compared with multiple injection insulin treatment. Among other concepts, metformin, pioglitazone, incretin-based drugs such as GLP-1 receptor agonists, sodium-glucose cotransporter inhibitors, and pramlintide can improve insulin resistance, either directly or indirectly. However, considering the current issues of high cost, side effects, limited efficacy, and their off-label status, these agents in people with T1D are not widely used in routine clinical care at present.

Physical activity and sedentary behaviour in relation to body composition, estimated insulin sensitivity and arterial stiffness in adults with type 1 diabetes

AIMS

To examine the association of daily PA levels and sedentary behaviour with body composition, estimated insulin sensitivity, and arterial stiffness in adults with type 1 diabetes (T1D).

METHODS

Cross-sectional study in adults with T1D (n = 54). PA levels (daily steps, and time in moderate-to-vigorous intensity PA (MVPA)) and sedentary behaviour were measured using accelerometry for 7 days (McRoberts® DynaPort MoveMonitor). Cardiopulmonary exercise test for VO2max. Anthropometrics were collected, and body composition (total and % of fat mass (FMtot, FM%), total and % of lean mass (LMtot, LM%), and estimated visceral adipose tissue (VAT)) volume was assessed with dual energy X-ray-absorptiometry (DXA). Estimates of insulin sensitivity were determined (estimated glucose disposal rate (eGDR) and total daily insulin dose). Arterial stiffness was assessed with carotid-femoral pulse wave velocity (cf-PWV (m/s); SphygmoCor®).

RESULTS

Lower 10-years HbA1c associated moderately with all PA measures. Favourable moderate associations were also found between PA measures and BMI, waist, VAT but not FM and LM. PA measures were favourably associated with a lower total daily insulin dose and higher eGDR. All PA parameters associated moderately with cf-PWV however not independent from traditional risk factors. VO2max was inversely associated with cf-PWV independent of age, T1D duration and 24-hour mean blood pressure.

CONCLUSIONS

Higher levels of PA, lower sedentary behaviour and greater exercise capacity are favourably associated with long-term glycaemic control, body composition, insulin dosage, estimated insulin sensitivity and arterial stiffness in adults with T1D. Therefore, regular PA and limiting sedentary time should be encouraged to improve metabolic and cardiovascular health in this population. Future longitudinal studies should explore mutual interactions and synergistic effects of PA on these outcomes.

Short, frequent, light-intensity walking activity improves postprandial vascular-inflammatory biomarkers in people with type 1 diabetes: The SIT-LESS randomized controlled trial

AIM

To examine the effect of interrupting prolonged sitting with short, frequent, light-intensity activity on postprandial cardiovascular markers in people with type 1 diabetes (T1D).

MATERIALS AND METHODS

In a randomized crossover trial, 32 adults with T1D (mean ± SD age 28 ± 5 years, glycated haemoglobin 67.9 ± 12.6 mmol/mol, 17 women) completed two 7-h laboratory visits separated by >7 days. Participants either remained seated for 7 h (SIT) or interrupted sitting with 3-min bouts of self-paced walking at 30-min intervals commencing 1 h after each meal (SIT-LESS). Physical activity, insulin regimen, experimental start times, and meal consumption were standardized during each arm. Plasma levels of interleukin (IL)-1β, tumour necrosis factor (TNF)-α, plasminogen activator inhibitor (PAI)-1 and fibrinogen were sampled at baseline, 3.5 and 7 h, and assessed for within- and between-group effects using a repeated measures ANOVA. The estimated glucose disposal rate was used to determine the insulin resistance status.

RESULTS

Vascular-inflammatory parameters were comparable between SIT and SIT-LESS at baseline (p > .05). TNF-α, IL-1β, PAI-1 and fibrinogen increased over time under SIT, whereas these rises were attenuated under SIT-LESS (p < .001). Specifically, over the 7 h under SIT, postprandial increases were detected in TNF-α, IL-1β, PAI-1 and fibrinogen (+67%, +49%, +49% and +62%, respectively; p < .001 for all). Conversely, the SIT-LESS group showed no change in IL-1β (-9%; p > .50), whereas reductions were observed in TNF-α, PAI-1 and fibrinogen (-22%, -42% and -44%, respectively; p < .001 for all). The intervention showed enhanced effects in insulin-resistant individuals with T1D.

CONCLUSIONS

Interrupting prolonged sitting with light-intensity activity ameliorates postprandial increases in vascular-inflammatory markers in T1D.

TRIAL REGISTRATION

The trial was prospectively registered (ISRCTN13641847).

Lifestyle in Emerging Adults with Type 1 Diabetes Mellitus: A Qualitative Systematic Review

Emerging adulthood is a transitional stage with significant lifestyle changes, making it especially challenging for those living with type 1 diabetes mellitus. This systematic review synthesizes qualitative research to explore how emerging adulthood (18-29 years) influences lifestyle behaviors in individuals with type 1 diabetes mellitus. CINAHL, Cochrane Library, Global Health, Nursing & Allied Health Premium, PsycINFO, PubMed, Scopus, and WOS were searched for original qualitative studies addressing the lifestyle of 18-31-year-olds with type 1 diabetes mellitus, published between January 2010 and March 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Thirty-five studies met the inclusion criteria and their findings were categorized into eight topics (emotions and feelings, nutrition, perceptions, risky behaviors, self-care, sleep, social relationships, and stigma) using meta-aggregation, as outlined in the Joanna Briggs Institute Manual for Evidence Synthesis. The spontaneity characteristic of emerging adulthood can undermine self-care. This is because new environments, schedules, and relationships encountered during this life stage often lead to the neglect of diabetes management, owing to the various social, academic, and occupational demands. This review highlights the necessity of creating health promotion strategies tailored to the unique lifestyle aspects of emerging adults with type 1 diabetes mellitus.