Dr Sean Lanting

Backgrounds and aims: Obesity and diabetes independently contribute to cutaneous microvascular dysfunction via pathological processes that are not fully understood. We sought to determine if obesity severity is associated with cutaneous microvascular dysfunction and measures of peripheral arterial disease in adults with type 2 diabetes in cross-sectional observational study design. Methods and results: Primary outcomes were post-occlusive reactive hyperaemia as determined by laser-Doppler fluxmetry (peak flux post-occlusion, time to peak flux post-occlusion, peak as a percentage of baseline, and area under the curve [AuC] index post-occlusion to pre-occlusion). Secondary outcomes were ankle- and toe-brachial indices (ABI and TBI) and systolic toe pressure. Thirty-six participants (20 men, 16 women) with mean age 55 ± 8 years, BMI of 36 ± 5 kg/m2 and duration of diabetes 8 ± 6 years underwent measurements. After adjusting for age and duration of diabetes, SAT and total percentage body fat were able to explain 29% (p = 0.001) and 20% (p = 0.01) of variance of AuC index models, as well as 29% (p = 0.02) and 18% (p = 0.02) of peak as a percentage of baseline models, respectively. Though TBI demonstrated moderate, significant correlations with SAT (r:0.37, p = 0.04) and total percentage body fat (r:0.39, p = 0.03), these were not upheld by regression analyses. Neither ABI nor systolic toe pressure significantly correlated with any measure of adiposity or obesity. Conclusion: These findings demonstrate impairment in cutaneous microvascular function related to adiposity and obesity severity in adults with type 2 diabetes, suggesting that obesity may pathologically effect cutaneous microvascular function in the absence of overt macrovascular disease, warranting further investigation.

Background: Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and¿reductions in liver fat¿content. However, there are limited data concerning the relationship between CRF and liver fat¿content in adults with varying degrees of metabolic dysfunction. Methods: The aim of this study was to examine the association between CRF, liver fat¿content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional¿analysis. CRF was determined via a graded exercise test. Liver fat content was assessed via proton magnetic resonance spectroscopy and insulin resistance was assessed via homeostatic model of insulin resistance (HOMA-IR). A¿partial correlation analysis, controlling for age and gender, was performed to determine the association between CRF, demographic, cardiometabolic, and anthropometric variables. Independent t tests were performed to compare¿cardiometabolic outcomes between participants with T2D and participants without T2D. Results: Seventy-two adults (46% male) with a mean age of 49.28 ± 10.8 years, BMI of 34.69 ± 4.87 kg/m2, liver fat content¿of 8.37 ± 6.90%,¿HOMA-IR of 3.07¿± 2.33 and CRF of 21.52 ± 3.77 mL/kg/min participated in this study. CRF was inversely associated with liver fat content (r = - 0.28, p = 0.019) and HOMA-IR (r = - 0.40, p < 0.001). Participants with T2D had significantly higher liver fat content (+ 3.66%, p = 0.024) and HOMA-IR (+ 2.44, p¿< 0.001)¿than participants without T2D. Participants with T2D tended to have lower CRF than participants without T2D (- 1.5 ml/kg/min, p = 0.094). Conclusion: CRF was inversely associated with liver fat¿content and insulin resistance. Participants with T2D had lower CRF than those without T2D, however, the difference was not statistically significant. Further longitudinal studies are required to elucidate the relationship between CRF and the progression of obesity-related diseases such as T2D. Registration: ACTRN12614001220651 (retrospectively registered on the 19th November 2014) and ACTRN12614000723684 (prospectively registered on the 8th July 2014).

Background: A weight bearing ankle equinus has adverse effects on forefoot plantar pressure variables in older adults with diabetes, but it is unclear if this is also the case in older adults without diabetes. Methods: 40 older adults with diabetes (88% type 2, mean diabetes duration 17.6 ± 14.8 years) and 40 older adults without diabetes, matched for age (±3 years), sex and BMI (±2 BMI units) were included (63% female, mean age 72 ± 4 years, BMI 30 ± 4 kg/m2). Primary outcomes were prevalence of a weight bearing equinus and evaluation of barefoot forefoot plantar pressures in older adults with and without diabetes. Findings: A weight bearing equinus was present in 37.5% and 27.5% of the diabetes and non-diabetes group respectively with no significant difference between groups (p = 0.470). People with diabetes and equinus displayed higher peak pressure (808 versus 540 kPa, p = 0.065) and significantly higher pressure-time integral (86 versus 68 kPa/s, p = 0.030) than people with diabetes and no equinus group. The non-diabetes equinus group had significantly higher peak pressure (665 versus 567 kPa, p = 0.035) than those with no diabetes and no equinus, but no difference in pressure-time integral. Interpretation: A high prevalence of a weight bearing equinus was detected in older adults with and without diabetes, with associated increases in plantar pressures. As an equinus has been associated with many foot pathologies this study's findings suggest that clinicians should check for the presence of a weight bearing ankle equinus in all older adults.