Low-density lipoprotein cholesterol in adolescents and young adults with type 1 diabetes: Data from the Australasian Diabetes Data Network registry.

AIM: To determine low-density lipoprotein cholesterol (LDL-C) screening frequency and levels, and factors associated with elevated LDL-C, in Australasian youth with type 1 diabetes (T1D). METHODS: Data were extracted from the Australasian Diabetes Data Network (ADDN), a prospective clinical quality registry, on all T1D healthcare visits attended by young people aged 16-25 years (with T1D duration of >1 year) between January 2011 and December 2020. The primary outcomes were elevated LDL-C > 2.6 mmol/L (100 mg/dL) and threshold for treatment: >3.4 mmol/L (130 mg/dL), according to consensus guidelines. Multivariable Generalised Estimated Equations (GEE) were used to examine factors associated with elevated LDL-C across all visits. RESULTS: A cohort of 6338 young people (52.6% men) were identified, of whom 1603 (25.3%) had ≥1 LDL-C measurement documented. At last measurement, mean age, age at T1D diagnosis and T1D duration were 18.3 ± 2.4, 8.8 ± 4.5 and 8.9 ± 4.8 years, respectively. LDL-C was elevated in 737 (46.0%) and at the treatment threshold in 250 (15.6%). In multivariable GEE elevated LDL-C continuously was associated with older age (OR = 0.07; 0.01-0.13, p = 0.02), female sex (OR = 0.31; 0.18-0.43; p < 0.001), higher HbA1c (OR = 0.04; 0.01-0.08; p = 0.01) and having an elevated BMI (OR = 0.17, 0.06-0.39, p < 0.001). CONCLUSIONS: LDL-C screening and levels are suboptimal in this cohort, increasing future cardiovascular complication risk. There is an urgent need to understand how healthcare services can support improved screening and management of dyslipidaemia in this population.

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.

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.

Thyroid autoimmunity in Type 1 diabetes: systematic review and meta-analysis.

AIMS: To review the incidence and evidence for screening for thyroid autoimmunity and thyroid dysfunction in Type 1 diabetes. METHODS: Systematic review and meta-analysis. Inclusion criteria were prospective cohort studies screening for thyroid autoimmunity and/or dysfunction (defined as an abnormal thyroid-stimulating hormone level) in Type 1 diabetes. Exclusion criteria included pregnancy and thyroid dysfunction before diabetes onset. Outcomes examined were: incidence of thyroid autoimmunity and/or dysfunction; association between thyroid autoimmunity and dysfunction; and cost-effectiveness. Data sources were MEDLINE, EMBASE, the Cochrane Library, manual searching and contact with authors, with limitations to English language and human studies. Meta-analysis was performed using random effects models. RESULTS: We identified 14 eligible studies, involving 2972 young people and 789 adults with Type 1 diabetes. Follow-up ranged from 1-18 years. None of the studies were of good methodological quality (Newcastle Ottowa Scale score > 7). The incidence of thyroid dysfunction (11 studies) ranged from 27 (95% CI 15-45) to 246 (95% CI 118-453) per 10 000 patient-years and thyroid autoimmunity (four studies) from 13 (95% CI 0.3-71) to 326 (95% CI 194-510). The risk of thyroid dysfunction was higher in those with thyroid autoimmunity: summary risk ratio 25 (95% CI 9-71) and was higher in children (49, 95% CI 16-150) compared with adults (7, 95% CI 3-13). No studies examined cost-effectiveness of screening. CONCLUSIONS: There is a markedly increased risk of thyroid dysfunction in people with Type 1 diabetes and thyroid autoimmunity. The optimal method or frequency of screening could not be determined from available data. Future studies should examine whether screening improves clinical outcomes in this population.

Plateau of adiposity in Australian children diagnosed with Type 1 diabetes: a 20-year study.

AIMS: To examine temporal trends in anthropometry in children with Type 1 diabetes from Sydney, Australia. METHODS: We conducted a retrospective study in a total of 1975 children with Type 1 diabetes, aged <16 years, between 1990 and 2009. Trends in height, weight and BMI standard deviation score after initial stabilization were examined by age group (<5 years, 5 to <10 years, 10 to 16 years) and time period of diagnosis (T1: 1990-1994, T2: 1995-1999; T3: 2000-2004 and T4: 2005-2009). Factors associated with BMI standard deviation score (time period, age group, gender and socio-economic status) were examined using multivariable linear regression. RESULTS: The mean BMI standard deviation score (±sd) increased between T1 and T2 (0.54 ± 1.14 vs 0.81 ± 1.14, P = 0.002), but remained steady thereafter (T3: 0.85 ± 1.11, T4: 0.87 ± 1.09; T2 to T4: P = 0.40). Similarly, the prevalence of overweight and obesity increased from T1 to T2 (26 to 35%, P = 0.01), but was unchanged thereafter (T3: 34%, T4: 34%; T2 to T4: P = 0.90). On multivariable regression analysis, a higher BMI standard deviation score was associated with younger age (≥5 years vs <5 years, ß=-0.40, 95% CI -0.51 to -0.28, P < 0.001), later time period (T2 to T4 vs T1, ß=0.30, 95% CI 0.16-0.45, P < 0.001) and male gender (ß=0.25, 95% CI 0.15-0.34, P < 0.001). CONCLUSION: The prevalence of overweight and obesity has remained unchanged in children at diagnosis of Type 1 diabetes over 15 years. These findings suggest that higher adiposity alone cannot account for the continued rising incidence of Type 1 diabetes in recent years.

Coeliac disease in Type 1 diabetes from 1990 to 2009: higher incidence in young children after longer diabetes duration.

AIMS: To determine the incidence of coeliac disease in young people with Type 1 diabetes and to examine the effect of age at diabetes onset and disease duration. METHODS: This was a clinic-based observational cohort study of 4379 people aged ≤ 18 years (49% male) between 1990 and 2009 from Sydney, Australia. Screening for coeliac disease was performed at diagnosis and 1-2 yearly using anti-endomysial and/or anti-tissue transglutaminase immunoglobulin A (IgA) antibodies. Coeliac disease was diagnosed by small bowel biopsy based on Marsh score ≥ III. RESULTS: Coeliac disease was confirmed by biopsy in 185; of these, 61 (33%) were endomysial or tissue transglutaminase IgA antibody-positive at diabetes diagnosis. Mean age at diabetes onset was 6.6 ± 4.0 vs. 8.4 ± 4.1 years in those without coeliac disease (P < 0.001). Mean incidence was 7.7 per 1000 person years (95% CI 6.6-8.9) over 20 years. Incidence was higher in children aged < 5 years at diabetes diagnosis (10.4 per 1000 person years) vs. ≥ 5 years (6.4 per 1000), incidence rate ratio 1.6 (95% CI 1.2-2.2, P = 0.002). Coeliac disease was diagnosed after 2, 5 and 10 years of diabetes in 45, 78 and 94% of cases, respectively. Median time to coeliac disease diagnosis was longer in children aged < 5 years at diabetes onset (3.3 years) compared with older children (0.7 years, P < 0.001). CONCLUSIONS: Coeliac disease is common in young people with Type 1 diabetes; the risk is greatest with diabetes onset < 5 years, but after longer diabetes duration. Screening for coeliac disease should be performed at diabetes diagnosis and for at least 10 years in young children.

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.

The effect of prepubertal diabetes duration on diabetes. Microvascular complications in early and late adolescence.

OBJECTIVE: To define the significance of prepubertal diabetes duration in the development of diabetic microvascular complications in adolescents. RESEARCH DESIGN AND METHODS: Study A compares complications in 38 prepubertal (PreP) and 140 pubertal (Pub) subjects of the same age (10-14 years) and diabetes duration (3-12 years) to determine if the absence of puberty itself confers a lower risk of complications. Study B examines the importance of prepubertal and pubertal diabetes duration in 193 older adolescents (ages 15-22 years) with prepubertal onset of diabetes. Retinopathy status was assessed using stereoscopic fundus photography of seven fields per eye. Albumin excretion rate (AER) was assessed by three consecutive overnight urine collections, using a polyclonal radioimmunoassay. RESULTS: In study A, there were no significant differences between the PreP and Pub groups for retinopathy (27 vs. 29%, P = 0.8) or differences in elevated AER (17 vs. 31%, P = 0.1). In study B, longer prepubertal diabetes duration improved the prediction for retinopathy over postpubertal duration alone (P < 0.0005). No relationship with duration was found for elevated AER (> 7.5, > 15, and > 30 micrograms/min). CONCLUSIONS: Prepubertal subjects with diabetes did not have less retinopathy or elevated albumin excretion compared with pubertal subjects of the same age. Prepubertal diabetes duration is significantly related to the presence of retinopathy in adolescents.

CCR5 genotyping in an Australian and New Zealand type 1 diabetes cohort.

Infiltration of pancreatic tissue by autoreactive T-cells involves secretion of multiple cytokines and chemokine receptor expression. Genetically determined variation in cell surface expression of the chemokine receptor CCR5 may result in differences in inflammatory cell migration in response to relevant chemokines. Adolescents with type 1 diabetes (T1D) from Australia and New Zealand were genotyped for CCR5-delta32 (n = 626). The allele frequency was compared with that of 253 non-diabetic Australian adolescents and with that of 92 adults with systemic lupus erythematosus. A reduced allele frequency was seen in T1D compared with controls (0.092 vs. 0.123, p = 0.05). This difference was not seen for the cohort of patients with SLE (freq = 0.114). A reduction in the number of CCR5-delta32/delta32 homozygotes, who lack CCR5, in the T1D cohort was also seen and while not statistically significant (2 observed compared to 5.25 expected; p = 0.12) is interesting. These results suggest a partial protection from T1D for CCR5-delta32 homozygous individuals is possible and that CCR5 has a potential role in the pathogenesis of T1D.