Skin autofluorescence in people with type 1 diabetes and people without diabetes: An eight-decade cross-sectional study with evidence of accelerated aging and associations with complications.

AIM: To measure skin autofluorescence in youth (<18 y.o.) and adults (≥18 y.o.) and to assess its relationship with type 1 diabetes, chronic complications and smoking. METHODS: In a cross-sectional study (n = 383) skin autofluorescence was measured in 269 people with type 1 diabetes (67 with vascular complications) and 114 people without diabetes, covering eight decades of age. Associations of skin autofluorescence with demographics and traditional risk factors were assessed. RESULTS: Skin autofluorescence increased with age in people with diabetes: for those with complications it increased by a mean ± se of 0.029 ± 0.003 arbitrary units per year (r = 0.76) and, for those without complications, it increased by 0.028 ± 0.002 arbitrary units (r = 0.77). These increases were higher than for people without diabetes, whose skin autofluorescence increased by 0.022 ± 0.002 arbitrary units (r = 0.78) per year (p = 0.004). Mean ±se age-adjusted skin autofluorescence was higher in people with diabetes complications vs people without diabetes complications (1.85 ± 0.04 vs 1.66 ± 0.02 arbitrary units) and people without diabetes (1.48 ± 0.03 arbitrary units; all P < 0.0001). Age-adjusted skin autofluorescence was higher in current smokers and recent ex-smokers vs non-smokers and longer-term ex-smokers (1.86 ± 0.06 vs 1.63 ± 0.02 arbitrary units; P = 0.0005). Skin autofluorescence area under the receiver-operating characteristic curve was 0.89 (95% CI 0.85-0.94) for retinopathy and 0.56 (95% CI 0.47-0.65) for nephropathy. CONCLUSIONS: Skin autofluorescence increases with age, but faster in people with diabetes, particularly in those with complications and in smokers, consistent with accelerated aging. Skin autofluorescence may facilitate complication screening and prediction. Longitudinal studies are merited.

Early changes of arterial elasticity in Type 1 diabetes with microvascular complications - A cross-sectional study from childhood to adulthood.

AIM: To examine the trajectory of small artery elasticity (SAE) and pulse pressure (PP) in people with Type 1 diabetes and non-diabetic controls across the lifespan, and explore associations with microvascular complications (CX+). METHODS: This cross-sectional study included 477 Type 1 diabetes patients (188 with CX+, 289 without CX-) and 515 controls. Relationships between SAE and PP and age were evaluated using segmented linear regression. Logistic regression was used to assess the associations between microvascular complications (retinopathy and/or nephropathy) and SAE and PP. RESULTS: SAE peaked significantly later among controls than diabetic patients CX- vs. CX+ (21.2 vs. 20.4 vs. 17.6 years respectively, p < 0.001). In adults, mean SAE was significantly lower in CX+ vs. CX- vs. controls (6.8 vs. 7.8 vs. 8.0 ml/mm Hg × 10; p < 0.0001), and mean PP was significantly higher in CX+ vs CX- and controls (60 vs. 55 vs. 53 mm Hg; p < 0.0001). CONCLUSION: Type 1 diabetes CX+ subjects have an earlier peak and decline in SAE relative to CX- and controls, who did not differ. Lower SAE and higher PP were associated with increased odds of Type 1 diabetes complications in adults. These clinically applicable techniques demonstrate an association between accelerated vascular aging and vascular complications in diabetes.

Higher skin autofluorescence in young people with Type 1 diabetes and microvascular complications.

AIM: To test the hypothesis that non-invasive skin autofluorescence, a measure of advanced glycation end products, would provide a surrogate measure of long-term glycaemia and be associated with early markers of microvascular complications in adolescents with Type 1 diabetes. METHODS: Forearm skin autofluorescence (arbitrary units) was measured in a cross-sectional study of 135 adolescents with Type 1 diabetes [mean ± sd age 15.6 ± 2.1 years, diabetes duration 8.7 ± 3.5 years, HbA1c 72 ± 16 mmol/mol (8.7 ± 1.5%)]. Retinopathy, assessed using seven-field stereoscopic fundal photography, was defined as ≥1 microaneurysm or haemorrhage. Cardiac autonomic function was measured by standard deviation of consecutive RR intervals on a 10-min continuous electrocardiogram recording, as a measure of heart rate variability. RESULTS: Skin autofluorescence was significantly associated with age (R2 = 0.15; P < 0.001). Age- and gender-adjusted skin autofluorescence was associated with concurrent HbA1c (R2 = 0.32; P < 0.001) and HbA1c over the previous 2.5-10 years (R2 = 0.34-0.43; P < 0.002). Age- and gender-adjusted mean skin autofluorescence was higher in adolescents with retinopathy vs those without retinopathy [mean 1.38 (95% CI 1.29, 1.48) vs 1.22 (95% CI 1.17, 1.26) arbitrary units; P = 0.002]. In multivariable analysis, retinopathy was significantly associated with skin autofluorescence, adjusted for duration (R2 = 0.19; P = 0.03). Cardiac autonomic dysfunction was also independently associated with skin autofluorescence (R2 = 0.11; P = 0.006). CONCLUSIONS: Higher skin autofluorescence is associated with retinopathy and cardiac autonomic dysfunction in adolescents with Type 1 diabetes. The relationship between skin autofluorescence and previous glycaemia may provide insight into metabolic memory. Longitudinal studies will determine the utility of skin autofluorescence as a non-invasive screening tool to predict future microvascular complications.

QT interval, corrected for heart rate, is associated with HbA1c concentration and autonomic function in diabetes.

AIMS: To examine QT intervals corrected for heart rate (QTc) in adolescents with Type 1 diabetes compared with control subjects, and to determine associations with metabolic control and autonomic function. METHODS: Resting electrocardiogram recordings of 142 adolescents with Type 1 diabetes [mean (sd) age 15.3 (2.0) years, diabetes duration 9.0 (3.5) years, HbA1c 71 (17) mmol/mol or 8.7 (1.6)%] and 125 control subjects [mean (sd) age 15.7 (2.5) years] were used to calculate QTc duration and derive mean heart rate and heart rate variability (HRV) values. Linear and logistic regression models were used to examine the associations between QTc, metabolic control and autonomic function (HRV and pupillary function). RESULTS: QTc duration was not significantly different between subjects with Type 1 diabetes and control subjects (mean duration 392 vs 391 ms; P = 0.65). In the Type 1 diabetes group, QTc was positively associated with HbA1c [ß = 4 (95% CI 2, 6); P < 0.001] and inversely associated with severe hypoglycaemic events [ß = -10 (95% CI -20,-2); P = 0.01], less insulin/kg [ß = -12 (95% CI -22, -2); P = 0.024] and less HRV. In the Type 1 diabetes group, QTc in the highest quintile (≥409 ms) vs quintiles 1-4 had more pupillary abnormalities (83 vs 56%; P = 0.03), lower pupillary maximum constriction velocity (4.8 vs 5.3 mm/s; P = 0.04), higher heart rate (78 vs 72 beats per min; P = 0.02) and lower HRV (standard deviation of mean NN intervals 4.0 vs 4.3 ms, P = 0.004 and root-mean-square difference of successive NN intervals 3.7 vs 4.1 ms; P = 0.004). CONCLUSIONS: Although there are concerns about hypoglycaemia in general in people with Type 1 diabetes, chronic hyperglycaemia, rather than intermittent hypoglycaemia, appears to be more deleterious to autonomic cardiac function, even in adolescence. Longer QTc was associated with higher HbA1c concentration, lower risk of hypoglycaemia and autonomic dysfunction. Longitudinal studies are warranted.