Association Between HbA1c Variability and Risk of Microvascular Complications in Adolescents With Type 1 Diabetes

CONTEXT

There is a paucity of data regarding the association between glycosylated hemoglobin (HbA1c) variability and risk of microvascular complications in adolescents with type 1 diabetes (T1D).

OBJECTIVE

To investigate the association between HbA1c variability and risk of microvascular complications in adolescents with T1D.

DESIGN

Prospective cohort study from 1990 to 2014 (median follow-up, 8.1 y).

SETTING

Tertiary pediatric hospital.

PARTICIPANTS

A total of 1706 adolescents (aged 12-20 minimum diabetes duration 5 y) with median age of 15.9 years (interquartile range, 14.3-17.5) and diabetes duration of 8.1 years (6.3-10.8).

MAIN OUTCOME MEASURES

Glycemic variability was computed as the SD of all HbA1c measurements (SD-HbA1c) after diagnosis. Retinopathy was detected using 7-field fundal photography, renal function assessed using albumin excretion rate, peripheral neuropathy detected using thermal and vibration threshold testing, and cardiac autonomic neuropathy (CAN) detected using time- and frequency-domain analyses of electrocardiogram recordings. Generalized estimating equations were used to examine the relationship between complications outcomes and HbA1c variability, after adjusting for known risk factors, including HbA1c, diabetes duration, blood pressure, and lipids.

RESULTS

In multivariable analysis, SD-HbA1c was associated with early retinopathy (odds ratio [OR] 1.32; 95% confidence interval, 1.00-1.73), albuminuria (OR 1.81; 1.04-3.14), increased log10 albumin excretion rate (OR 1.10; 1.05-1.15) and CAN (OR 2.28; 1.23-4.21) but not peripheral neuropathy.

CONCLUSIONS

Greater HbA1c variability predicts retinopathy, early nephropathy, and CAN, in addition to established risk factors, in adolescents with T1D. Minimizing long term fluctuations in glycemia may provide additional protection against the development of microvascular complications.

Insulin Pump Therapy Is Associated with Lower Rates of Retinopathy and Peripheral Nerve Abnormality

OBJECTIVE

To compare rates of microvascular complications in adolescents with type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI).

RESEARCH DESIGN AND METHODS

Prospective cohort of 989 patients (aged 12-20 years; diabetes duration >5 years) treated with CSII or MDI for >12 months. Microvascular complications were assessed from 2000-14: early retinopathy (seven-field fundal photography), peripheral nerve function (thermal and vibration threshold testing), autonomic nerve abnormality (heart rate variability analysis of electrocardiogram recordings) and albuminuria (albumin creatinine ratio/timed overnight albumin excretion). Generalized estimating equations (GEE) were used to examine the relationship between treatment and complications rates, adjusting for socio-economic status (SES) and known risk factors including HbA1c and diabetes duration.

RESULTS

Comparing CSII with MDI: HbA1C was 8.6% [70mmol/mol] vs. 8.7% [72 mmol/mol]) (p = 0.7), retinopathy 17% vs. 22% (p = 0.06); microalbuminuria 1% vs. 4% (p = 0.07), peripheral nerve abnormality 27% vs. 33% (p = 0.108) and autonomic nerve abnormality 24% vs. 28% (p = 0.401). In multivariable GEE, CSII use was associated with lower rates of retinopathy (OR 0.66, 95% CI 0.45-0.95, p = 0.029) and peripheral nerve abnormality (OR 0.63, 95% CI 0.42-0.95, p = 0.026), but not albuminuria (OR 0.46, 95% CI 0.10-2.17, p = 0.33). SES was not associated with any of the complication outcomes.

CONCLUSIONS

In adolescents, CSII use is associated with lower rates of retinopathy and peripheral nerve abnormality, suggesting an apparent benefit of CSII over MDI independent of glycemic control or SES.

A pilot randomized controlled trial of a post-discharge program to support emerging adults with type 1 diabetes mellitus transition from pediatric to adult care

AIMS

There is a paucity of randomized controlled trials (RCT) examining transition from pediatric to adult care in type 1 diabetes mellitus (T1DM). This study aimed to determine if transition in T1DM is more effective with a comprehensive transition program (CTP) compared with standard clinical practice (SCP).

METHODS

This RCT recruited as young people left pediatric diabetes services. The trial co-ordinator provided CTP participants with standardized telephone communication support at week 1, and 3, 6, and 12 months post-discharge from pediatric care. SCP participants were briefly contacted at 6 and 12 months post-discharge to confirm transfer status; they received no other post-discharge contact as per usual practice. At 12 months, the primary outcomes were engagement and retention in the adult service and secondary outcomes included hemoglobin A1c (HbA1c), diabetes-related hospitalizations, microvascular complication appearance, and global self-worth.

RESULTS

Most CTP participants (11/14) and all SCP (12/12) participants (P = 0.2) transferred to an adult diabetes service; the median time to transfer was 14-15 wk. Overall, participants' frequency of adult diabetes service visits was sub-optimal but their retention in adult care was high. The only group difference was a higher HbA1c at baseline and follow-up in the CTP group. However, a general linear model found that follow-up HbA1c increased by 1.2% for each percentage increase in baseline HbA1c [95% confidence interval (0.4, 1.9; P = 0.01)], independent of treatment group.

CONCLUSIONS

Despite the challenges in recruiting adequate numbers, these findings provide valuable insights for future T1DM transition RCTs that are needed to build a more solid evidence-base in this field.

Interventions for Diabetic Retinopathy in Type 1 Diabetes: Systematic Review and Meta-Analysis

PURPOSE

To systematically review the effectiveness of systemic interventions for diabetic retinopathy (DR) in type 1 diabetes.

DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE and Cochrane Library were searched for studies published from January 1990 to December 2014. Randomized controlled trials and controlled cohort studies reporting incidence or progression of DR following systemic intervention were included. Two reviewers selected studies, extracted data, and assessed risk of bias. For each intervention, pooled outcomes were reported as relative risk (RR) estimates with 95% confidence intervals (CI).

RESULTS

Twenty-four studies involving 9302 patients met inclusion criteria. Incident DR was reduced by intensive vs conventional insulin therapy (RR 0.43; 95% CI 0.23-0.83), insulin pumps vs multiple daily injections (RR 0.45; 95% CI 0.24-0.83), and angiotensin receptor blockade vs placebo (RR 0.65; 95% CI 0.49-0.85). The benefit of insulin pumps over multiple daily infections was independent of HbA1c. DR progression was reduced by intensive vs conventional insulin therapy (RR 0.63; 95% CI 0.43-0.92), angiotensin-converting enzyme inhibition vs placebo (RR 0.60; 95% CI 0.41-0.86), and islet cell transplantation vs medical therapy (RR 0.25; 95% CI 0.08-0.71).

CONCLUSIONS

Intensive insulin therapy, and specifically insulin pump therapy vs multiple daily injections, prevents DR in both adults and adolescents with type 1 diabetes. Antihypertensive agents provide protection in normotensive, normoalbuminuric adults. In patients with type 1 diabetes of longer duration, islet cell transplantation may be more effective than medical therapy. There is insufficient evidence for antilipid therapy or other systemic interventions.

Screening for Celiac Disease in Type 1 Diabetes: A Systematic Review

BACKGROUND AND OBJECTIVES

Prevalence rates of type 1 diabetes (T1D) and celiac disease (CD) vary from 1.6% to 16.4% worldwide. Screening guidelines are variable and not evidence based. Our aim was to conduct a systematic review of CD in T1D.

METHODS

Medline, Embase, and the Cochrane Library were searched. Studies were limited to those in English and in humans. We selected longitudinal cohort studies screening for CD in T1D with at least 5 years of follow-up. Screening rates, characteristics, and prevalence of biopsy-proven CD in people with T1D were extracted.

RESULTS

We identified 457 nonduplicate citations; 48 were selected for full-text review. Nine longitudinal cohort studies in 11,157 children and adolescents with 587 cases of biopsy-proven CD met the inclusion criteria. Median follow-up was 10 years (range: 5-18 years). The weighted pooled prevalence of CD was 5.1% (95% confidence interval: 3.1-7.4%). After excluding 41 cases with CD onset before T1D, CD was diagnosed in 218 of 546 (40%) subjects within 1 year, in 55% within 2 years, and in 79% within 5 years of diabetes duration. Two studies (478 cases) reported higher rates of CD in children aged <5 years at T1D diagnosis. The duration of follow-up varied across the included studies. CD screening frequency progressively decreased with increased T1D duration.

CONCLUSIONS

Because most cases of CD are diagnosed within 5 years of T1D diagnosis, screening should be considered at T1D diagnosis and within 2 and 5 years thereafter. CD screening should be considered at other times in patients with symptoms suggestive of CD. More research is required to determine the screening frequency beyond 5 years of diabetes duration.

Cardiac autonomic dysfunction is associated with high-risk albumin-to-creatinine ratio in young adolescents with type 1 diabetes in AdDIT (adolescent type 1 diabetes cardio-renal interventional trial)

OBJECTIVE

This study examined the association between cardiac autonomic dysfunction and high albumin-to-creatinine ratio (ACR) in adolescents with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Adolescents recruited as part of a multicenter screening study (n = 445, 49% female, aged 10-17 years, mean duration 6.9 years; mean HbA1c 8.4%, 68 mmol/mol) underwent a 10-min continuous electrocardiogram recording for heart rate variability analysis. Time-domain heart rate variability measures included baseline heart rate, SD of the R-R interval (SDNN), and root mean squared difference of successive R-R intervals (RMSSD). Spectral analysis included sympathetic (low-frequency) and parasympathetic (high-frequency) components. Standardized ACR were calculated from six early morning urine collections using an established algorithm, reflecting age, sex, and duration, and stratified into ACR tertiles, where the upper tertile reflects higher nephropathy risk.

RESULTS

The upper-tertile ACR group had a faster heart rate (76 vs. 73 bpm; P < 0.01) and less heart rate variability (SDNN 68 vs. 76 ms, P = 0.02; RMSSD 63 vs. 71 ms, P = 0.04). HbA1c was 8.5% (69 mmol/mmol) in the upper tertile vs. 8.3% (67 mmol/mol) in the lower tertiles (P = 0.07). In multivariable analysis, upper-tertile ACR was associated with faster heart rate (β = 2.5, 95% CI 0.2-4.8, P = 0.03) and lower RMSSD (β = -9.5, 95% CI -18.2 to -0.8, P = 0.03), independent of age and HbA1c.

CONCLUSIONS

Adolescents at potentially higher risk for nephropathy show an adverse cardiac autonomic profile, indicating sympathetic overdrive, compared with the lower-risk group. Longitudinal follow-up of this cohort will further characterize the relationship between autonomic and renal dysfunction and the effect of interventions in this population.

Arterial elasticity in obese adolescents with clinical features of insulin resistance

OBJECTIVE

To determine whether arterial elasticity differs between obese adolescents with clinical insulin resistance (IR), type 1 diabetes (T1D) and healthy non-obese controls.

METHODS

This cross-sectional study evaluated 69 adolescents with clinical IR, 91 with T1D and 63 age-matched (10- to 18-year-old) controls. Arterial elasticity was measured using radial tonometry pulse-wave analysis. Stepwise multiple regression analyses were performed to assess the determinants of the small and large arterial elasticity indices (SAEI and LAEI).

RESULTS

SAEI and LAEI raw values were higher in the IR group than the controls, and these did not differ between the T1D and control groups. Weight and diastolic blood pressure (DBP) were significant predictors of SAEI. After adjustment for weight and DBP, SAEI decreased by 0.65 mL/mmHg × 100 for each 1-year increase in age in the IR group. SAEI was not different across the groups after controlling for weight and DBP. Height was the strongest predictor of LAEI which remained higher in the IR group after controlling for height and blood pressure.

CONCLUSION

Obese adolescents with clinical IR have a higher SAEI, which declines with age; this may reflect a pathway to an increased risk of premature cardiovascular disease.

Early atherosclerosis relates to urinary albumin excretion and cardiovascular risk factors in adolescents with type 1 diabetes: Adolescent type 1 Diabetes cardio-renal Intervention Trial (AdDIT)

OBJECTIVE

The origins of cardiovascular and renal disease in type 1 diabetes begin during childhood. We aimed to evaluate carotid (cIMT) and aortic intima-media thickness (aIMT) and their relationship with cardiovascular risk factors and urinary albumin excretion in adolescents with type 1 diabetes in the Adolescent Type 1 Diabetes cardio-renal Intervention Trial (AdDIT).

RESEARCH DESIGN AND METHODS

A total of 406 adolescents with type 1 diabetes, who were 14.1 ± 1.9 years old with type 1 diabetes duration of 6.7 ± 3.7 years, and 57 age-matched control subjects provided clinical and biochemical data and ultrasound measurements of vascular structure (cIMT and aIMT). Vascular endothelial and smooth muscle function was also measured in 123 of 406 with type 1 diabetes and all control subjects.

RESULTS

In type 1 diabetic subjects, mean/maximal aIMT (P < 0.006; <0.008), but not mean/maximal cIMT, was greater than in control subjects. Mean/maximal aIMT related to urinary albumin-to-creatinine ratio (multiple regression coefficient [SE], 0.013 [0.006], P = 0.03; 0.023 [0.007], P = 0.002), LDL cholesterol (0.019 [0.008], P = 0.02; 0.025 [0.011], P = 0.02), and age (0.010 [0.004], P = 0.004; 0.012 [0.005], P = 0.01), independent of other variables. Mean/maximal cIMT was greater in males (0.023 [0.006], P = 0.02; 0.029 [0.007], P < 0.0001), and mean cIMT related independently to systolic blood pressure (0.001 [0.001], P = 0.04). Vascular smooth muscle function related to aIMT and cIMT but not to urinary albumin excretion.

CONCLUSIONS

aIMT may be a more sensitive marker of atherosclerosis than cIMT in type 1 diabetes during mid-adolescence. Higher urinary albumin excretion, even within the normal range, is associated with early atherosclerosis and should direct clinical attention to modifiable cardiovascular risk factors.

Effect of fat loss on arterial elasticity in obese adolescents with clinical insulin resistance: RESIST study

CONTEXT

Reduced arterial elasticity contributes to an obesity-related increase in cardiovascular risk in adults.

OBJECTIVE

To evaluate the effect of fat loss on arterial elasticity in obese adolescents at risk of type 2 diabetes.

DESIGN

A secondary data analysis of the RESIST study was performed in two hospitals in Sydney, Australia.

PARTICIPANTS

The study included 56 subjects (ages, 10 to 17 y; 25 males) with prediabetes and/or clinical features of insulin resistance.

INTERVENTION

A 12-month lifestyle plus metformin intervention.

OUTCOMES

Arterial elasticity and systemic vascular resistance were measured using radial tonometry pulse contour analysis, percentage body fat (%BF) was measured by dual-energy x-ray absorptiometry, and insulin sensitivity index was derived from an oral glucose tolerance test and lipids.

RESULTS

Adolescents (n = 31) with decreased %BF (mean change [range], -4.4% [-18.3 to -0.01%]) after the intervention had significant increases in the mean large arterial elasticity index (mean change [95%CI], 5.1 [1.9 to 8.2] mL/mm Hg * 10; P = .003) and insulin sensitivity index (0.5 [0.1 to 0.9]; P = .010) and a decrease in systemic vascular resistance (-82 [-129 to -35] dyne * s * cm(-5); P = .001). There were no significant changes in these parameters in adolescents who increased their %BF. Nor was there any significant change in the mean small arterial elasticity index in either group.

CONCLUSION

Long-term follow-up of these adolescents is warranted to assess whether the observed changes in vascular elasticity will lead to a clinical benefit including reduced cardiovascular morbidity and mortality.

Insulin pump-associated adverse events in children and adolescents--a prospective study

BACKGROUND

Intensive insulin regimens are now the mainstay of modern, type 1 diabetes mellitus management. Insulin pumps (CSII) are a key technique used. Although there has been considerable study of outcomes, there are few recent data on CSII-associated adverse events (AEs) and their incidence and characteristics.

SUBJECTS AND METHODS

Phone calls to our 24-h diabetes support service were screened for CSII-associated AEs. Phone interviews were conducted with the parent/patient, within 96 h of the event. Interviews explored AE characteristics and the role of the user, as well as questions relating to outcome and the impact to the family and patient. Comparisons were made with clinic CSII patients not reporting an AE.

RESULTS

Over a 16-week study period, 50 confirmed AEs occurred in 45 of 405 (11.1%) patients. This was annualized to an AE incidence of 40 AEs/100 person-years. Pump malfunction and infusion set/site failures were the most common events reported, occurring in 27 (54.0%) and 18 (36.0%) AEs, respectively. A user- or education-related issue was implicated in 22 (44.0%) events. Pump replacement occurred in 19 of 50 occurrences (38.0%). Additionally, 16 (32.0%) reported a hospital admission or emergency department attendance as a consequence. When compared with those on CSII not reporting an AE, AEs were associated with age <10 years (odds ratio=3.2 [95% confidence interval, 1.7-6.1]) but not with gender, glycosylated hemoglobin, diabetes duration, or pumping duration.

CONCLUSIONS

This is the first prospective study to look at AEs in modern-generation insulin pumps. AEs appear common and should be anticipated. Their origin is multifactorial, with the pump, associated consumables, and the user all being important factors. Ongoing support and anticipatory education are essential to minimize pump-associated AEs and their impact.

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, β=-0.40, 95% CI -0.51 to -0.28, P < 0.001), later time period (T2 to T4 vs T1, β=0.30, 95% CI 0.16-0.45, P < 0.001) and male gender (β=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.

Heart rate variability in pubertal girls with type 1 diabetes: its relationship with glycaemic control, insulin resistance and hyperandrogenism

OBJECTIVE

To examine the association between glycaemic control, insulin resistance and hyperandrogenism on cardiac autonomic function in peripubertal girls with type 1 diabetes.

DESIGN

Prospective, clinic-based study of 125 girls with diabetes and 46 age-matched nondiabetic girls.

MEASUREMENTS

Heart rate variability (HRV) parameters derived from a 10-min ECG recording using LabChart Pro were as follows: standard deviation of mean NN intervals (SDNN), where NN = adjacent QRS complexes; root mean squared difference of successive NN intervals (RMSSD) - estimates of overall HRV; and low-/high-frequency (LF:HF) ratio - an estimate of the sympathovagal balance. Androgens and sex hormone binding globulin (SHBG) were measured in girls with diabetes, and free androgen index (FAI) calculated. HRV and anthropometry were measured in nondiabetic controls.

RESULTS

Adolescents with diabetes (median age 15·1 years [13·3-16·0], diabetes duration 7·0 years [4·6-10·0] and median HbA1c 8·4% [7·5-9·3]) had higher HR and lower HRV compared with controls. Using multivariate models in the diabetes group, higher HR was associated with higher HbA1c, total daily dose insulin/kg body weight and systolic BP standard deviation scores (SDS), whilst reduced HRV was associated with higher HbA1c (SDNN, RMSSD and LF:HF ratio), lower SHBG (SDNN and RMSSD) and higher weight SDS (LF:HF ratio). Higher FAI was associated with higher HR and reduced HRV measures in the univariate analyses only.

CONCLUSIONS

In adolescent girls with diabetes, reduced HRV parameters are associated with worse glycaemic control, lower SHBG and higher weight SDS. SHBG should be considered in the cardiac risk models for this population.

Family perceptions of insulin pump adverse events in children and adolescents

BACKGROUND

Insulin pumps (for continuous subcutaneous insulin infusion [CSII]) are used widely in type 1 diabetes mellitus. Although there has been considerable study of outcomes, there are few recent data on CSII-associated adverse events and no data on family perceptions of adverse events and their confidence in dealing with them.

SUBJECTS AND METHODS

We approached all families of children and adolescents ≤ 19 years of age on CSII attending the diabetes clinic over a 16-week clinic cycle. Participants completed a retrospective questionnaire examining issues over the previous 12 months. Data on pump adverse events as well as answers to questions pertaining to education and confidence were collected.

RESULTS

Our survey received a response rate of 99%, with 235 of the 238 families approached participating. In the preceding 12 months, 104 of 230 (45%) had reported at least one pump-related adverse event (either mechanical or set-related), with an associated 52 of 229 (23%) resulting in pump replacement. This equated to a minimum incidence density of 53 adverse events/100 person-years. Additionally, 18 of 230 (8%) reported a hospital admission or emergency department attendance as a consequence. Pump malfunction and infusion set/site failures were the most common events reported, with one or more events in 58 of 104 (56%) and 47 of 104 (45%), respectively. Adverse events, excluding set/site failures, were associated with older age (13.1 ± 3.4 years vs. 11.9 ± 4 years; P = 0.02).

CONCLUSIONS

This is the first study to look at family perceptions of adverse events while using modern CSII. It highlights a high self-reported rate of CSII-related adverse events, pump replacement, and subsequent presentation to the hospital. Potential areas for additional targeted education are identified. Further prospective study examining pump adverse event characteristics and incidence is warranted.

Puberty as an accelerator for diabetes complications

Much is written about how difficult it is to deal with diabetes during adolescence, and rightly so. Less is understood as to how puberty may be an accelerator of vascular complications. With the increase in childhood diabetes, complication risks need to be revisited in relation to puberty and the secular increase in adiposity. Recent data suggest greater risk for severe vascular complications in those with diabetes during puberty, compared with young people who develop diabetes after puberty. It is also widely recognized that higher hemoglobin A1c (HbA1c) results are often seen during the pubertal period. This article will review complication outcomes in relation to puberty and examine mechanisms by which puberty may modify risk above glycemic exposure, and possible gender disparities in the risk of complications in the adolescent period.

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.

Early elevation of albumin excretion rate is associated with poor gluten-free diet adherence in young people with coeliac disease and diabetes

AIMS

There are conflicting data on microvascular complications in coexisting Type 1 diabetes and coeliac disease. We compared complications rates in youth with or without coeliac disease and examined the association between gluten-free diet adherence and complications.

METHODS

This was a comparative study of adolescents (2510 without coeliac disease, 129 with coeliac disease); 60 (47%) did not adhere to a gluten-free diet--defined as elevated anti-tissue transglutaminase or endomysial immunoglobulin A titres. Retinopathy was detected using 7-field fundal photography and albumin excretion rate by timed overnight urine collections, with early elevation defined as albumin excretion rate ≥ 7.5 μg/min. Logistic regression was used to examine the association between complications and explanatory variables, including coeliac disease vs. no coeliac disease, gluten-free diet adherence vs. non-adherence, diabetes duration and HbA1c .

RESULTS

Median age at last assessment was 16.5 years. Those with coeliac disease vs. those without were younger at diabetes diagnosis (7.1 vs. 8.6 years, P < 0.001) and had longer diabetes duration (9.3 vs. 7.2 years, P < 0.001). HbA1c was lower in those with coeliac disease vs. those without (67 vs. 70 mmol/mol, 8.3 vs. 8.6%, P = 0.04) and adherence to a gluten-free diet vs. non-adherence (66 vs. 72 mmol/mol, 8.2 vs. 8.7%, P = 0.003). There were no differences in complication rates between those with coeliac disease vs. those without (retinopathy 22 vs. 23%, elevated albumin excretion rate 31 vs. 28%). Non-adherence to a gluten-free diet was associated with elevated albumin excretion rate (40 vs. 23%, P = 0.04). In multivariable logistic regression, elevated albumin excretion rate was associated with non-adherence to a gluten-free diet (odds ratio 2.37, 95% CI 1.04-5.40, P = 0.04) and diabetes duration (odds ratio 1.13, 95% CI 1.02-1.25, P = 0.03), but not HbA1c .

CONCLUSIONS

While glycaemic control is better in patients with coeliac disease, non-adherence to a gluten-free diet is associated with elevated albumin excretion rate. The possible protection of a gluten-free diet on complications warrants further investigation.

Autonomic neuropathy in young people with type 1 diabetes: a systematic review

Autonomic neuropathy is an under-recognized complication of diabetes, although it affects multiple organ systems and has widespread clinical manifestations including orthostatic hypotension, exercise intolerance, gastroparesis, diarrhea, constipation, and urinary incontinence. The most severe consequences include hypoglycemia unawareness and cardiovascular dysfunction. Autonomic neuropathy is also implicated in sudden unexplained deaths in otherwise healthy young people--the ‘dead in bed syndrome’. In adults, cardiovascular autonomic neuropathy is an independent predictor of mortality, predominantly due to cardiovascular disease, nephropathy, and hypoglycemia. While overt autonomic neuropathy is rare in childhood and adolescence, subclinical signs of autonomic dysfunction are common, and can be found soon after diabetes diagnosis. Risk factors for autonomic neuropathy in young people include diabetes duration, poor glycemic control, and presence of aldose reductase gene (AKR1B1) polymorphisms, specifically the Z-2/Z-2 genotype. Autonomic dysfunction is accelerated by puberty.

Vitamin D deficiency is not associated with changes in retinal geometric parameters in young people with type 1 diabetes

Changes in retinal geometric parameters predict risk and progression of diabetic retinopathy (DR). We have shown that vitamin D deficiency (VDD) is associated with DR. We hypothesized that VDD mediates changes in retinal geometric parameters. Retinal vascular geometric parameters were assessed using a semiautomated computer program in photographs from young people with type 1 diabetes (T1D) (n = 481) and summarized as central retinal arteriolar and venular equivalents (CRAE, CRVE), fractal dimension, length-diameter ratio, branching angle and curvature tortuosity. Parameters were compared between those with and without DR and VDD (25-hydroxyvitamin D concentration ≤ 50 nmol/L). Retinal vascular geometric parameters were also compared across quartiles of vitamin D levels. Median CRVE was higher in patients with DR compared with those without (median (IQR) CRVE 247.3  μ m (31.3) versus 238.8  μ m (23.5), P = 0.01). Fractal dimension was marginally greater in patients without VDD (1.49 (0.06) versus 1.47 (0.07) P = 0.03). There was no difference in CRAE, CRVE, length-diameter ratio, branching angle, and curvature tortuosity between those with and without VDD and across quartiles of 25OHD. In conclusion, DR is associated with higher CRVE in young people with T1D; however, VDD is not associated with changes in retinal vascular geometric measures, suggesting an earlier role in the time course of DR pathogenesis.

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.

Plantar fascia thickness is longitudinally associated with retinopathy and renal dysfunction: a prospective study from adolescence to adulthood

AIM

The aim was to study the longitudinal relationship between plantar fascia thickness (PFT) as a measure of tissue glycation and microvascular (MV) complications in young persons with type 1 diabetes (T1DM).

METHODS

We conducted a prospective longitudinal cohort study of 152 (69 male) adolescents with T1DM who underwent repeated MV complications assessments and ultrasound measurements of PFT from baseline (1997-2002) until 2008. Retinopathy was assessed by 7-field stereoscopic fundal photography and nephropathy by albumin excretion rate (AER) from three timed overnight urine specimens. Longitudinal analysis was performed using generalized estimating equations (GEE).

RESULTS

Median (interquartile range) age at baseline was 15.1 (13.4-16.8) years, and median follow-up was 8.3 (7.0-9.5) years, with 4 (3-6) visits per patient. Glycemic control improved from baseline to final visit [glycated hemoglobin (HbA1c) 8.5% to 8.0%, respectively; p = .004]. Prevalence of retinopathy increased from 20% to 51% (p < .001) and early elevation of AER (>7.5 μg/min) increased from 26% to 29% (p = .2). A greater increase in PFT (mm/year) was associated with retinopathy at the final assessment (ΔPFT 1st vs. 2nd-4th quartiles, χ(2) = 9.87, p = .02). In multivariate GEE, greater PFT was longitudinally associated with retinopathy [odds ratio (OR) 4.6, 95% confidence interval (CI) 2.0-10.3] and early renal dysfunction (OR 3.2, CI 1.3-8.0) after adjusting for gender, blood pressure standard deviation scores, HbA1c, and total cholesterol.

CONCLUSIONS

In young people with T1DM, PFT was longitudinally associated with retinopathy and early renal dysfunction, highlighting the importance of early glycemic control and supporting the role of metabolic memory in MV complications. Measurement of PFT by ultrasound offers a noninvasive estimate of glycemic burden and tissue glycation.

Retinal vascular geometry predicts incident renal dysfunction in young people with type 1 diabetes

OBJECTIVE

To examine the relationship between retinal vascular geometry parameters and development of incident renal dysfunction in young people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective cohort study of 511 adolescents with type 1 diabetes of at least 2 years duration, with normal albumin excretion rate (AER) and no retinopathy at baseline while attending an Australian tertiary-care hospital. AER was quantified using three overnight, timed urine specimen collections and early renal dysfunction was defined as AER >7.5 μg/min. Retinal vascular geometry (including length-to-diameter ratio [LDR] and simple tortuosity [ST]) was quantified from baseline retinal photographs. Generalized estimating equations were used to examine the relationship between incident renal dysfunction and baseline venular LDR and ST, adjusting for age, diabetes duration, glycated hemoglobin (A1C), blood pressure (BP), BMI, and cholesterol.

RESULTS

Diabetes duration at baseline was 4.8 (IQR 3.3-7.5) years. After a median 3.7 (2.3-5.7) years follow-up, 34% of participants developed incident renal dysfunction. In multivariate analysis, higher retinal venular LDR (odds ratio 1.7, 95% CI 1.2-2.4; quartile 4 vs. 1-3) and lower venular ST (1.6, 1.1-2.2; quartile 1 vs. 2-4) predicted incident renal dysfunction.

CONCLUSIONS

Retinal venular geometry independently predicted incident renal dysfunction in young people with type 1 diabetes. These noninvasive retinal measures may help to elucidate early mechanistic pathways for microvascular complications. Retinal venular geometry may be a useful tool to identify individuals at high risk of renal disease early in the course of diabetes.

Retinal arteriolar tortuosity is associated with retinopathy and early kidney dysfunction in type 1 diabetes

PURPOSE

To examine the association of retinal vessel tortuosity with diabetic retinopathy and early nephropathy in type 1 diabetes.

DESIGN

Cross-sectional.

METHODS

A total of 1159 participants with type 1 diabetes aged 12 to 20 years, attending diabetes clinics in Children's Hospital at Westmead, Sydney, Australia between 1990 and 2002, were included. Retinal photography and clinical examinations were performed during the baseline visit to assess diabetic retinopathy and albumin excretion rate (AER). Retinal vessel tortuosity was measured from digitized retinal photographs using a semi-automated computer program by a single grader masked to participants' characteristics. Diabetic retinopathy was defined as ETDRS level ≥21 (mild nonproliferative retinopathy) and early kidney dysfunction was defined as AER ≥7.5 μg/min.

RESULTS

Of 944 patients (81.4%), 85 (9.0%) had signs of retinopathy only, 250 (26.5%) had early kidney dysfunction only, and 85 (9.0%) had both retinopathy and early kidney dysfunction. In multivariate analysis, higher arteriolar tortuosity was associated with retinopathy (odds ratio [OR] 2.01, 95% confidence interval [CI] 1.23-3.29, the highest quartile vs the remaining 3 quartiles), early kidney dysfunction (OR 1.56, 95% CI 1.06-2.28, per standard deviation [SD] increase), or coexistence of both complications (OR 1.96, 95% CI 1.21-3.24, the highest quartile vs the remaining 3 quartiles).

CONCLUSIONS

Greater retinal arteriolar tortuosity was independently associated with retinopathy and early stage of nephropathy in type 1 diabetes. These findings may offer the potential of quantitative measurement of retinal vessel tortuosity for diabetic complication risk assessment.

Microvascular complications assessment in adolescents with 2- to 5-yr duration of type 1 diabetes from 1990 to 2006

OBJECTIVE

Microvascular complications occur in adolescents with type 1 diabetes, although guidelines vary as to when screening should commence and prevalence data for those with ≤5-yr duration are limited. We therefore investigated trends in prevalence of early microvascular complications over 17 yr.

RESEARCH DESIGN AND METHODS

819 adolescents (54% female) aged 11-17 yr with 2- to 5-yr diabetes duration were assessed for complications at a tertiary pediatric diabetes clinic between 1990 and 2006. Early retinopathy was detected using seven-field fundal photography, albumin excretion rate (AER) by timed overnight urine collections and peripheral nerve function by thermal/vibration threshold at the foot. Results were analyzed by age, time period of assessment, and duration.

RESULTS

Early retinopathy declined from 1990 to 2002 (16-7%, p < 0.01), then remained unchanged until 2006. Early elevation of AER (≥7.5 µg/min) and microalbuminuria (≥20 µg/min) did not change over time, whereas peripheral nerve abnormalities increased (14-28%, p < 0.01). Median hemoglobin A1c improved (8.7-8.2%, p < 0.01), in parallel with increased total daily insulin dose and injections per day (p < 0.01). Body mass index standard deviation score increased over time (0.55-0.79, p < 0.01). In multivariate logistic regression, early retinopathy was associated with earlier time period [odds ratio (OR) 0.68, confidence interval (CI) 0.55-0.85, p < 0.01] and older age (OR 1.19, CI 1.02-1.39, p = 0.03). AER ≥ 7.5 µg/min was associated with older age (1.19, 1.06-1.34, p < 0.01) and longer diabetes duration (OR 1.28, CI 1.02-1.62, p = 0.04) and height-adjusted peripheral nerve abnormalities with later time period (OR 1.26, CI 1.05-1.50, p = 0.01).

CONCLUSIONS

Early complications are not uncommon in adolescents with 2- to 5-yr diabetes duration, despite more intensive management in recent years.

Continued reduction in the prevalence of retinopathy in adolescents with type 1 diabetes: role of insulin therapy and glycemic control

OBJECTIVE

To examine trends in microvascular complications in adolescents with type 1 diabetes between 1990 and 2009 in Sydney, Australia.

RESEARCH DESIGN AND METHODS

We used analysis of complications in 1,604 adolescents (54% female, aged 12-20 years, median duration 8.6 years), stratified by four time periods using Generalized Estimation Equations as follows: T1 (1990-1994), T2 (1995-1999), T3 (2000-2004), and T4 (2005-2009). Early retinopathy was detected using seven-field fundal photography, albumin excretion rate (AER) using timed overnight urine collections, and albumin-to-creatinine ratio (ACR) and peripheral nerve function using thermal and vibration threshold.

RESULTS

Retinopathy declined (53, 38, 23, and 12%; P < 0.001), as did borderline elevation of AER/ACR (45, 30, 26, and 30%; P < 0.001) and microalbuminuria (8, 4, 3, and 3%; P = 0.006). Multiple daily injections (MDI)/continuous subcutaneous insulin infusion (CSII) use increased (17, 54, 75, and 88%; P < 0.001), median HbA(1c) decreased (9.1, 8.9, 8.5, and 8.5%; P < 0.001), and severe hypoglycemia was unchanged (6, 8, 10, and 7%; P = 0.272). Retinopathy was associated with diabetes duration (odds ratio [OR] 1.12 [95% CI 1.08-1.17]), age (1.13 [1.06-1.20]), HbA(1c) (1.16 [1.08-1.25]), systolic blood pressure (BP) SDS (1.31 [1.16-1.48]), socioeconomic disadvantage (1.42 [1.04-1.95]), and 1 to 2 injections per day (vs. MDI/CSII; 1.35 [1.05-1.73]); borderline AER/ACR with male sex (1.32 [1.02-1.70]), age (1.19 [1.12-1.26]), HbA(1c) (1.18 [1.08-1.29]), weight SDS (1.31 [1.21-1.53]), insulin dose per kilograms (1.64 [1.13-2.39]), 1 to 2 injections per day (1.41 [1.08-1.84]), and socioeconomic disadvantage (1.68 [1.23-2.31]); and microalbuminuria with age (1.14 [1.01-1.29]), HbA(1c) (1.20 [1.05-1.37]), diastolic BP SDS (1.76 [1.26-2.46]), and 1 to 2 injections per day (1.95 [1.11-3.41]).

CONCLUSIONS

The decline in retinopathy supports contemporary guidelines that recommend lower glycemic targets and use of MDI/CSII in children and adolescents with type 1 diabetes.

Managing ethically questionable parental requests: growth suppression and manipulation of puberty

Doctors sometimes struggle with ethically challenging requests for treatment from children's parents. For instance, we have recently had two requests by parents of children, a girl and a boy, each with a severe developmental disability, for hormonal therapy to suppress growth and puberty: the girl's parents requested, in addition, hysterectomy and mastectomy. We propose a reliable approach to assessing the ethical and legal aspects of these and other requests for 'non-therapeutic' treatment of a minor who lacks the capacity to give informed consent. We argue that a doctor should first assess whether the request is one that he or she can, in conscience, accede to, and then, if it is, seek the authorisation of a court. We outline considerations relevant to the doctor's assessment of both the ethical issues and to the need for court authorisation.

Retinal vascular geometry predicts incident retinopathy in young people with type 1 diabetes: a prospective cohort study from adolescence

OBJECTIVE

To examine the association between retinal vascular geometry and subsequent development of incident retinopathy in young patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

A prospective cohort study of 736 people with type 1 diabetes aged 12 to 20 years, retinopathy-free at baseline, attending an Australian tertiary care hospital. Retinopathy was determined from seven-field retinal photographs according to the modified Airlie House Classification. Retinal vascular geometry, including length/diameter ratio (LDR) and simple tortuosity (ST), was quantified in baseline retinal photographs. Generalized estimating equations were used to determine risk of retinopathy associated with baseline LDR and ST, adjusting for other factors.

RESULTS

After a median 3.8 (interquartile range 2.4-6.1) years of follow-up, incident retinopathy developed in 287 of 736 (39%). In multivariate analysis, lower arteriolar LDR (odds ratio 1.8 [95% CI 1.2-2.6]; 1st vs. 4th quartile) and greater arteriolar ST (1.5 [1.0-2.2]; 4th vs. 1st quartile) predicted incident retinopathy after adjusting for diabetes duration, sex, A1C, blood pressure, total cholesterol, and BMI. In subgroup analysis by sex, LDR predicted incident retinopathy in male and female participants (2.1 [1.1-4.0] and 1.7 [1.1-2.7]; 1st vs. 4th quartiles, respectively) and greater arteriolar ST predicted incident retinopathy in male participants (2.4 [1.1-4.4]; 4th vs. 1st quartile) only.

CONCLUSIONS

Lower arteriolar LDR and greater ST were independently associated with incident retinopathy in young people with type 1 diabetes. These vascular geometry measures may serve as risk markers for diabetic retinopathy and provide insights into the early structural changes in diabetic microvascular complications.

Vitamin D deficiency is associated with retinopathy in children and adolescents with type 1 diabetes

OBJECTIVE

To examine the hypothesis that vitamin D deficiency (VDD) is associated with an increased prevalence of microvascular complications in young people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

In a cross-sectional study of 517 patients, 25-hydroxyvitamin D was measured. Retinopathy was assessed by 7-field stereoscopic retinal photography, peripheral neuropathy by thermal and vibration threshold testing, and microalbuminuria by albumin excretion rate or albumin-to-creatinine ratio.

RESULTS

Retinopathy prevalence was higher in cases with VDD versus sufficiency (18 vs. 9%, P = 0.02); deficiency was not associated with microalbuminuria or neuropathy. In logistic regression, retinopathy was associated with VDD (odds ratio 2.12 [95% CI 1.03-4.33]), diabetes duration (1.13, 1.05-1.23), and HbA(1c) (1.24, 1.02-1.50).

CONCLUSIONS

VDD is associated with an increased prevalence of retinopathy in young people with type 1 diabetes. The inflammatory and angiogenic effects of VDD may contribute to early retinal vascular damage; however, further investigations are warranted.

Complications of childhood diabetes and the role of technology

Technology for detecting vascular complications of childhood diabetes has already helped many children and youth by allowing for the early detection and intervention of impending or present problems as the result of the diabetes state. Prior to the advent of screening, young people developed clinical disease, in particular visual loss and renal impairment that often rapidly progressed to end-stage disease. With the advent of laser photocoagulation, which dramatically reduced visual loss from diabetic retinopathy, the importance of early detection and treatment of micro and macrovascular complications prior to clinical symptoms became apparent. Many technological advances are now being applied to the pediatric diabetes population, in either clinical care or the research setting. For example, retinal photography makes screening more accessible and more meaningful to adolescents with diabetes and can be used in large screening programs, for teleophthalmology, clinical trials and in geographically remote areas. Quantitative measures used to assess microvascular structure may be useful in monitoring interventions in the future. Quantitative sensory tests can monitor nerve dysfunction, but evaluations such as intraepidermal nerve fibre pathology and cornea confocal microscopy may be more sensitive to diagnose neuropathic complications in youth. B-mode ultrasonography can assess vascular function by measuring endothelium-dependent flow mediated dilatation and changes in the intima-media thickness of the carotid and aorta. It is the purpose of this manuscript to explore the role of present and future technological advances (Table 1) in young people with diabetes.

Cystic fibrosis-related diabetes in children--gaps in the evidence?

As the life span of patients with cystic fibrosis has increased, so has the prevalence of cystic fibrosis-related diabetes mellitus. However, screening practices for cystic fibrosis-related diabetes mellitus vary widely, which affects accurate estimates of the health burden of this comorbidity. The management of prediabetes and hyperglycemia is an increasingly important aspect of care in patients with cystic fibrosis, but few studies have specifically addressed the management of cystic fibrosis-related diabetes mellitus. Previous studies support the use of insulin for the treatment of patients with this disorder, but the evidence for its use in patients with cystic fibrosis and impaired glucose tolerance is poor. Nutritional management is currently guided by dietary recommendations for individuals with cystic fibrosis, with little evidence specific to the dietary management of patients with cystic fibrosis-related diabetes mellitus. Additionally, microvascular complications have become more frequent as a result of the rise in life expectancy of these patients, yet to date no intervention studies have addressed prevention or management of diabetic complications in patients with cystic fibrosis. A strong evidence base is needed to guide the management of patients with cystic fibrosis-related diabetes mellitus and its complications.

Alterations in retinal microvascular geometry in young type 1 diabetes

OBJECTIVE

To describe retinal microvascular geometric parameters in young patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes (aged 12-20 years) had clinical assessments and retinal photography following standardized protocol at a tertiary-care hospital in Sydney. Retinal microvascular geometry, including arteriolar and venular tortuosity, branching angles, optimality deviation, and length-to-diameter ratio (LDR), were measured from digitized photographs. Associations of these geometric characteristics with diabetes duration, A1C level, systolic blood pressure (SBP), and other risk factors were assessed.

RESULTS

Of 1,159 patients enrolled, 944 (81.4%) had gradable photographs and 170 (14.7%) had retinopathy. Older age was associated with decreased arteriolar (P = 0.024) and venular (P = 0.002) tortuosity, and female subjects had larger arteriolar branching angle than male subjects (P = 0.03). After adjusting for age and sex, longer diabetes duration was associated with larger arteriolar branching angle (P <or= 0.001) and increased arteriolar optimality deviation (P = 0.018), higher A1C was associated with increased arteriolar tortuosity (>8.5 vs. <or=8.5%, P = 0.008), higher SBP was associated with decreased arteriolar LDR (P = 0.002), and higher total cholesterol levels were associated with increased arteriolar LDR (P = 0.044) and decreased venular optimality deviation (P = 0.044). These associations remained after controlling for A1C, retinal vessel caliber, and retinopathy status and were seen in subjects without retinopathy.

CONCLUSIONS

Key diabetes-related factors affect retinal microvascular geometry in young type 1 diabetes, even in those without evidence of retinopathy. These early retinal alterations may be markers of diabetes microvascular complications.

Cortisol response to general anaesthesia for medical imaging in children

OBJECTIVE

The cortisol response to surgical stress has been frequently studied, and recommendations developed for steroid replacement in adrenally insufficient patients. There are currently no guidelines, however, for adrenal hormone replacement during anaesthesia alone. The objective of this study was to characterize the normal cortisol response to general anaesthesia in the absence of a surgical procedure in children.

DESIGN

Prospective observational study.

PATIENTS

Thirty-seven children (aged 0.5-7 years) without known endocrine disease or cranial neoplasms undergoing outpatient magnetic resonance imaging, under general anaesthesia for investigation of nonacute problems in a tertiary referral paediatric hospital.

MEASUREMENTS

Serum cortisol and salivary cortisol were measured before and after anaesthesia and during recovery.

RESULTS

The mean cortisol level was 303 (± 117) nmol/l at induction, 396 (± 241) nmol/l at emergence from anaesthesia and 584 (± 218) nmol/l during recovery. A stress response (increase in serum cortisol >550 nmol/l) occurred in 23% of children at emergence and in 52% of children at recovery. Eight children (31%) actually demonstrated a decrease in cortisol levels during anaesthesia, without an increase in complications. Mean salivary cortisol levels were 6.5 ± 4.8 nmol/l before induction, 23.5 ± 13.8 nmol/l at emergence from anaesthesia and 26.9 ± 21.6 nmol/l during recovery. A stress response (an increase in salivary cortisol greater than seven-fold) occurred in 26% of children during the study.

CONCLUSIONS

While some children demonstrated a rise in their cortisol levels in response to anaesthesia without surgery, the response was variable and often more pronounced during recovery. There was consistently no classic stress response.

Retinal vascular fractal dimension and risk of early diabetic retinopathy: A prospective study of children and adolescents with type 1 diabetes

OBJECTIVE

To examine the prospective association of retinal vascular fractal dimension with diabetic retinopathy risk in young people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a hospital-based prospective study of 590 patients aged 12-20 years with type 1 diabetes free of retinopathy at baseline. All patients had seven-field retinal photographs taken of both eyes. Incident retinopathy was ascertained from retinal photographs taken at follow-up visits. Fractal dimension was measured from baseline photographs using a computer-based program following a standardized protocol.

RESULTS

Over a mean +/- SD follow-up period of 2.9 +/- 2.0 years, 262 participants developed mild nonproliferative diabetic retinopathy (15.0 per 100 person-years). After adjusting for age, sex, diabetes duration, A1C, and other risk factors, we found no association between retinal vascular fractal dimension and incident retinopathy.

CONCLUSIONS

Retinal vascular fractal dimension was not associated with incident early diabetic retinopathy in this sample of children and adolescents with type 1 diabetes.

Quantitative assessment of early diabetic retinopathy using fractal analysis

OBJECTIVE

Fractal analysis can quantify the geometric complexity of the retinal vascular branching pattern and may therefore offer a new method to quantify early diabetic microvascular damage. In this study, we examined the relationship between retinal fractal dimension and retinopathy in young individuals with type 1 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional study of 729 patients with type 1 diabetes (aged 12-20 years) who had seven-field stereoscopic retinal photographs taken of both eyes. From these photographs, retinopathy was graded according to the modified Airlie House classification, and fractal dimension was quantified using a computer-based program following a standardized protocol.

RESULTS

In this study, 137 patients (18.8%) had diabetic retinopathy signs; of these, 105 had mild retinopathy. Median (interquartile range) retinal fractal dimension was 1.46214 (1.45023-1.47217). After adjustment for age, sex, diabetes duration, A1C, blood pressure, and total cholesterol, increasing retinal vascular fractal dimension was significantly associated with increasing odds of retinopathy (odds ratio 3.92 [95% CI 2.02-7.61] for fourth versus first quartile of fractal dimension). In multivariate analysis, each 0.01 increase in retinal vascular fractal dimension was associated with a nearly 40% increased odds of retinopathy (1.37 [1.21-1.56]). This association remained after additional adjustment for retinal vascular caliber.

CONCLUSIONS

Greater retinal fractal dimension, representing increased geometric complexity of the retinal vasculature, is independently associated with early diabetic retinopathy signs in type 1 diabetes. Fractal analysis of fundus photographs may allow quantitative measurement of early diabetic microvascular damage.

Retinal arteriolar dilation predicts retinopathy in adolescents with type 1 diabetes

OBJECTIVE

Alterations in retinal vascular caliber may reflect early subclinical microvascular dysfunction. In this study, we examined the association of retinal vascular caliber to incident retinopathy in young patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective cohort study of 645 initially retinopathy-free type 1 diabetic patients, aged 12-20 years. Participants had seven-field stereoscopic retinal photographs taken of both eyes at baseline and follow-up. Retinal vascular caliber was measured from baseline photographs using a computer-based program following a standardized protocol. Incident retinopathy was graded according to the modified Airlie House classification from follow-up photographs.

RESULTS

Over a median follow-up of 2.5 years, 274 participants developed retinopathy (14.8 per 100 person-years). After adjustments for age, sex, diabetes duration, glycemia, mean arterial blood pressure, BMI, and cholesterol levels, larger retinal arteriolar caliber (fourth versus first quartile) was associated with a more than threefold higher risk of retinopathy (hazard rate ratio 3.44 [95% CI 2.08-5.66]). Each SD increase in retinal arteriolar caliber was associated with a 46% increase in retinopathy risk (1.46 [1.22-1.74]). This association was stronger in female than in male participants. After similar adjustments, retinal venular caliber was not consistently associated with incident retinopathy.

CONCLUSIONS

Retinal arteriolar dilatation predicts retinopathy development in young patients with type 1 diabetes. Our data suggest that arteriolar dysfunction may play a critical role in the pathogenesis of early diabetic retinopathy and that computer-based retinal vascular caliber measurements may provide additional prognostic information regarding risk of diabetes microvascular complications.

Role of blood pressure in development of early retinopathy in adolescents with type 1 diabetes: prospective cohort study

OBJECTIVE

To examine the relation between blood pressure and the development of early retinopathy in adolescents with childhood onset type 1 diabetes.

DESIGN

Prospective cohort study.

SETTING

Diabetes Complications Assessment Service at the Children's Hospital at Westmead, Sydney, Australia.

PARTICIPANTS

1869 patients with type 1 diabetes (54% female) screened for retinopathy with baseline median age 13.4 (interquartile range 12.0-15.2) years, duration 4.9 (3.1-7.0) years, and albumin excretion rate of 4.4 (3.1-6.8) microg/min plus a subgroup of 1093 patients retinopathy-free at baseline and followed for a median 4.1 (2.4-6.6) years.

MAIN OUTCOME MEASURES

Early background retinopathy; blood pressure.

RESULTS

Overall, retinopathy developed in 673 (36%) participants at any time point. In the retinopathy-free group, higher systolic blood pressure (odds ratio 1.01, 95% confidence interval 1.003 to 1.02) and diastolic blood pressure (1.01, 1.002 to 1.03) were predictors of retinopathy, after adjustment for albumin excretion rate (1.27, 1.13 to 1.42), haemoglobin A(1c) (1.08, 1.02 to 1.15), duration of diabetes (1.16, 1.13 to 1.19), age (1.13, 1.08 to 1.17), and height (0.98, 0.97 to 0.99). In a subgroup of 1025 patients with albumin excretion rate below 7.5 microg/min, the cumulative risk of retinopathy at 10 years' duration of diabetes was higher for those with systolic blood pressure on or above the 90th centile compared with those below the 90th centile (58% v 35%, P=0.03). The risk was also higher for patients with diastolic blood pressure on or above the 90th centile compared with those below the 90th centile (57% v 35%, P=0.005).

CONCLUSIONS

Both systolic and diastolic blood pressure are predictors of retinopathy and increase the probability of early retinopathy independently of incipient nephropathy in young patients with type 1 diabetes.

Methylenetetrahydrofolate reductase and methionine synthase reductase gene polymorphisms and protection from microvascular complications in adolescents with type 1 diabetes

Folate status has been associated with endothelial dysfunction in adolescents with type 1 diabetes, and elevated total plasma homoocyst(e)ine (tHcy) is a risk for vascular disease in the non-diabetic population. Polymorphisms in genes involved in folate and homocysteine metabolism are implicated in vascular disease. We aimed to determine whether polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) genes are risk factors for early microvascular disease in a large group of adolescents with type 1 diabetes. Four hundred and eighty adolescents were screened annually for retinopathy and microalbuminuria for a median of 4 yr. Molecular analysis for the polymorphisms 677C-->T, 1298A-->C in MTHFR, and 66A-->G in MTRR was performed. The MTRR 66GG genotype reduced the risk for elevated albumin excretion rate (AER) (OR 0.47, CI 0.25, 0.88, p = 0.018) and showed a trend to reduced risk for microalbuminuria (OR 0.27, CI 0.06-1.21, p = 0.09). Survival without elevated AER was increased with the MTRR 66GG genotype (12.4 vs. 9.7 yr, p = 0.04) and with the MTHFR 1298CC genotype (15.2 vs. 10.2 yr, p = 0.007). Conversely, survival without retinopathy was reduced with the MTHFR 677TT and MTRR 66GG combined genotype (6.2 vs. 10.2 yr, p = 0.015). The MTRR 66GG and MTHFR 1298 CC genotypes may confer protection against early nephropathy, possibly because they are associated with lower tHcy. The MTHFR 677 TT was only related to earlier onset retinopathy in combination with MTRR 66GG.

Association between p.Leu54Met polymorphism at the paraoxonase-1 gene and plantar fascia thickness in young subjects with type 1 diabetes

OBJECTIVE

In type 1 diabetes, plantar fascia, a collagen-rich tissue, is susceptible to glycation and oxidation. Paraoxonase-1 (PON1) is an HDL-bound antioxidant enzyme. PON1 polymorphisms have been associated with susceptibility to macro- and microvascular complications. We investigated the relationship between plantar fascia thickness (PFT) and PON1 gene variants, p.Leu54Met, p.Gln192Arg, and c.-107C>T, in type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a cross-sectional study of 331 adolescents with type 1 diabetes (162 male and 169 female). PFT was assessed by ultrasound, PON1 was assessed by genotyping with PCR and restriction fragment-length polymorphism, and serum PON1 activity was assessed by rates of hydrolysis of paraoxon and phenylacetate.

RESULTS

Median (interquartile range) age was 15.4 (13.5-17.3) years, and diabetes duration was 7.6 (4.9-10.6) years. The distribution of p.Leu54Met genotypes was LL 135 (40.8%), ML 149 (45%), and MM 47 (14.2%). PFT was abnormal (>1.7 mm) in 159 adolescents (48%). In multivariate analysis, predictors of abnormal PFT were ML/LL versus MM p.Leu54Met polymorphism (odds ratio 3.84 [95% CI 1.49-9.82], P = 0.005); BMI (percentile) (1.02 [1.01-1.03], P = 0.007); systolic blood pressure (percentile) (1.01 [1.00-1.02], P = 0.03); and male sex (3.29 [1.98-5.46], P < 0.001).

CONCLUSIONS

Thickening of the plantar aponeurosis occurs predominantly in overweight and male adolescents with type 1 diabetes. The MM genotype at PON1 p.Leu54Met is associated with a reduced risk of abnormal PFT.

The addition of rosiglitazone to insulin in adolescents with type 1 diabetes and poor glycaemic control: a randomized-controlled trial

OBJECTIVE

To evaluate the effect of rosiglitazone, an insulin sensitizer, on glycaemic control and insulin resistance in adolescents with type 1 diabetes mellitus (T1DM) RESEARCH DESIGN AND METHODS: Randomized, double-blind, placebo-controlled crossover trial of rosiglitazone (4 mg twice daily) vs. placebo (24 wk each, with a 4 wk washout period). Entry criteria were diabetes duration >1 yr, age 10-18 yr, puberty (>or=Tanner breast stage 2 or testicular volume >4 mL), insulin dose >or=1.1 units/kg/day, and haemoglobin A1c (HbA1c) >8%. Responses to rosiglitazone were compared with placebo using paired t-tests.

RESULTS

Of 36 adolescents recruited (17 males), 28 completed the trial. At baseline, age was 13.6 +/- 1.8 yr, HbA1c 8.9 +/- 0.96%, body mass index standard deviation scores (BMI-SDS) 0.94 +/- 0.74 and insulin dose 1.5 +/- 0.3 units/kg/day. Compared with placebo, rosiglitazone resulted in decreased insulin dose (5.8% decrease vs. 9.4% increase, p = 0.02), increased serum adiponectin (84.8% increase vs. 26.0% decrease, p < 0.01), increased cholesterol (+0.5 mmol/L vs. no change, p = 0.02), but no significant change in HbA1c (-0.3 vs. -0.1, p = 0.57) or BMI-SDS (0.08 vs. 0.04, p = 0.31). Insulin sensitivity was highly variable in the seven subjects who consented to euglycaemic hyperinsulinaemic clamps. There were no major adverse effects attributable to rosiglitazone.

CONCLUSION

The addition of rosiglitazone to insulin did not improve HbA1c in this group of normal weight adolescents with T1DM.