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.

Plantar fascia thickness, a measure of tissue glycation, predicts the development of complications in adolescents with type 1 diabetes

OBJECTIVE

Direct measurement of collagen glycation requires skin biopsy, which is invasive. We hypothesized that measurement of plantar fascia thickness (PFT) by ultrasound is an alternative index of tissue glycation and a marker of microvascular disease.

RESEARCH DESIGN AND METHODS

This was a prospective longitudinal study of microvascular complications in 344 adolescents with type 1 diabetes, whose PFT was assessed by ultrasound at baseline. Retinopathy was assessed by seven-field fundal photography, albumin excretion rate (AER) measured from three consecutive timed overnight urine specimens, autonomic neuropathy by pupillometry and cardiovascular tests, and peripheral neuropathy by vibration and thermal thresholds. Longitudinal analysis was performed using generalized estimating equations with baseline PFT, duration, and A1C as explanatory variables.

RESULTS

At first assessment, median (interquartile range) age was 15.1 (13.5-17.2) years and diabetes duration was 8.5 (6.0-11.5) years. Median follow up was 3.2 (2.1-4.5) years with a median of 4 (2-13) complications assessments per patient. In multivariate analysis, baseline PFT (abnormal in 132 subjects, 38%) predicted subsequent development of retinopathy (odds ratio 2.4 [95% CI 1.1-5.0]), elevated AER (2.24 [1.05-5.11]), peripheral neuropathy (2.3 [1.2-4.41]), and autonomic neuropathy (4.94 [2.46-9.91]). Limited joint mobility was present in only 4%.

CONCLUSIONS

PFT is a significant predictor of the subsequent development of complications in type 1 diabetes, suggesting that glycation and oxidation of collagen in soft tissues may be independent risk factors for microvascular complications.

Identifying children at particular risk of long-term diabetes complications

Formerly a 'taboo' subject, long-term complications are now being increasingly discussed with the family by the health-care team. Identifying potential predictors and establishing early intervention can change the course of these complications in the young patient with diabetes. Although the most recognized risk factor is glycaemic exposure, the development of diabetes complications is likely to result from an interaction between genetic and environmental factors. Other major environmental risk factors are hypertension, smoking, higher body mass index and lipid disorders. This article will concentrate on specific paediatric aspects, including the impact of puberty; endothelial dysfunction and genetic susceptibility. Endothelial function assessed by flow-mediated dilatation is a non-invasive method that has been suitable for use in children and adolescents. In type 1 diabetes mellitus children, endothelium dysfunction has been documented among patients with short diabetes duration and has been correlated to folate status, triglyceride and low-density lipoprotein cholesterol levels. Studies in the paediatric population have also revealed an association of diabetes complications with genetic variants in the renin-angiotensin system, polyol pathway, lipid oxidation and folate metabolism. Currently, achieving the best glycaemic control remains the gold standard for prevention of long-term diabetes complications in the clinical context. However, recent identification of genetic markers and development of research tools that predict long-term complications might have a potential role as instruments in assessing the effectiveness of intervention in the early course of the disease.

Autonomic nerve testing predicts the development of complications: a 12-year follow-up study

OBJECTIVE

Cardiac autonomic nerve tests have predicted increased mortality in adults with diabetes, predominantly due to nephropathy, cardiac disease, and hypoglycemia. The significance of subclinical autonomic nerve test abnormalities has not been systematically studied in adolescents. We aimed to reassess an adolescent cohort, whose autonomic nervous system had been tested 12 years earlier by both pupillometry and cardiovascular tests.

RESEARCH DESIGN AND METHODS

From 1990 to 1993, adolescents with type 1 diabetes (n = 335) were assessed for autonomic neuropathy (median age 14.7 years [interquartile range 13.0-16.8], duration of diabetes 6.3 years [4.0-9.6], and A1C 8.3% [7.5-9.4]). Between 2003 and 2005, contact was made with 59% of the original group. Individual assessment 12 years later included completion of a validated hypoglycemia unawareness questionnaire (n = 123) and urinary albumin-to-creatinine ratio (n = 99) and retinal (n = 102) screening, as well as analysis of reports from external doctors (n = 35).

RESULTS

At baseline, there was no difference in age, duration of diabetes, or complications between those who participated in the follow-up phase (n = 137) and those who did not participate (n = 196). However, baseline A1C was lower in the follow-up participants (8.2 vs. 8.5% for participants vs. nonparticipants, respectively, P = 0.031). At 12 years of follow-up, 93% were aware and 7% were unaware that they had hypoglycemia; 32 (31%) had no retinopathy, but 10% required laser therapy, and 80 (81%) had no microalbuminuria. Small pupil size at baseline was independently associated with the development of microalbuminuria (odds ratio 4.36 [95% CI 1.32-14.42], P = 0.016) and retinopathy (4.83 [1.3-17.98], P = 0.019) but not with the development of hypoglycemia unawareness. There was no association with baseline cardiovascular tests and the development of complications 12 years later.

CONCLUSIONS

In this study, we found an association between baseline pupillometry tests and the presence of microalbuminuria and retinopathy at 12 years of follow-up. This suggests that pupillometry abnormalities may be early indicators of patients who are at high risk of future microvascular disease.

Decline in neurophysiological function after 7 years in an adolescent diabetic cohort and the role of aldose reductase gene polymorphisms

OBJECTIVE

This 7-year longitudinal study examines the potential impact of aldose reductase gene (AKR1B1) polymorphisms on the decline of nerve function in an adolescent diabetic cohort.

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes (n = 262) were assessed with three cardiovascular autonomic tests (heart rate variation during deep breathing, Valsalva maneuver, and during standing from a lying position) and pupillometry (resting pupil diameter, constriction velocity, and reflex amplitude), thermal, and vibration thresholds on the foot. Genotyping was performed for promoters (C-106T and C-12G), (CA)(n) dinucleotide repeats, and intragenic BamH1 polymorphism.

RESULTS

Median time between first and last assessment was 7.0 years (interquartile range 5.1-11.1), with a median of five assessments (four to seven) per individual. At first assessment, median age was 12.7 years (11.7-13.9), median duration was 5.3 years (3.4-8.0), and median HbA(1c) was 8.5% (7.8-9.3). All tests declined over time except for two cardiovascular autonomic tests and vibration discrimination. Faster decline in maximum constriction velocity was found to associate with the Z-2 allele (P = 0.045), Z-2/Z-2 (P = 0.026). Slower decline in hot thermal threshold discrimination associated with Z+2 (P = 0.044), Z+2/Z+2 (P < 0.0005), Z+2/T (P = 0.038), and bb (P = 0.0001).

CONCLUSIONS

Most autonomic and quantitative sensory nerve testings declined over time. AKR1B1 polymorphisms were strongly associated with the rate of decline of these complications.

Natural history and risk factors for microalbuminuria in adolescents with type 1 diabetes: a longitudinal study

OBJECTIVE

To describe the natural history and risk factors for persistent microalbuminuria in children and adolescents with type 1 diabetes followed for up to 15 years.

RESEARCH DESIGN AND METHODS

This study contained a longitudinal cohort of 972 patients; analysis of baseline risk factors was performed using logistic regression and predictors over time using survival analysis. Albumin excretion rate was measured on three consecutive timed overnight urine collections on at least two occasions. Normoalbuminuria was defined as a median albumin excretion rate < 7.5 microg/min, borderline microalbuminuria as 7.5-20 microg/min, and microalbuminuria as 20-200 microg/min. Microalbuminuria was further classified as persistent if its duration was >12 months. Median age was 12.7 years (interquartile range 11.5-14.4) and diabetes duration 6.5 years (4.1-9.3) at first assessment, and median follow-up was 6.2 years (range 1-15.3).

RESULTS

The incidence of persistent microalbuminuria was 4.6 (95% CI 3.3-6.1) per 1,000 patient-years. Predictors of persistent microalbuminuria from the first assessment using multiple logistic regression were high cholesterol (odds ratio 2.2 [95% CI 1.2-4.0]) and borderline microalbuminuria (2.5 [1.2-5.2]). Predictors using Cox regression were HbA(1c) (hazard ratio 1.4 [95% CI 1.1-1.7]), age at diagnosis (1.2 [1.1-1.3]), obesity (3.6 [0.8-15.5]), and insulin dose (2.7 [1.0-7.5]).

CONCLUSIONS

Children and adolescents with type 1 diabetes who have borderline microalbuminuria are more than twice as likely to develop persistent microalbuminuria. In addition to poor glycemic control, clinical markers of insulin resistance were associated with an increased risk of microalbuminuria.

Retinal vascular caliber and risk of retinopathy in young patients with type 1 diabetes

OBJECTIVE

To examine the relationship between retinal vascular caliber and incident retinopathy in children and adolescents with type 1 diabetes mellitus.

DESIGN

Hospital-based case-control study with prospective outcomes.

PARTICIPANTS

Cases and controls were selected from a cohort of children and adolescents 12 to 20 years old with type 1 diabetes followed up at a tertiary diabetes clinic. Cases were patients who developed incident diabetic retinopathy (n = 166) after at least 1 year of follow-up (> or =2 clinic visits), and controls were patients who had not developed retinopathy (n = 165) after > or =2 years of follow-up (> or =3 clinic visits). Baseline retinal photographs of cases and controls were digitized, and retinal vascular calibers were measured using a computer-assisted program by a grader masked to case-control status. These measurements were combined into summary indices reflecting the average arteriolar and venular calibers.

MAIN OUTCOME MEASURE

Development of diabetic retinopathy.

RESULTS

Incident retinopathy cases had retinal arteriolar calibers (mean +/- standard deviation [SD], 206.5+/-18.4 microm) significantly larger than those of controls (200.2+/-16.5 microm) (P = 0.004) but similar retinal venular calibers (329.1+/-14.7 microm in cases vs. 326.4+/-15.1 microm in controls, P = 0.312). After adjusting for age, gender, diabetes duration, glycated hemoglobin levels, blood pressure, body mass index, and pubertal stage, larger arteriolar caliber was predictive of risk of diabetic retinopathy (odds ratio, 1.44 per SD increase in arteriolar caliber; 95% confidence interval, 1.11-1.86).

CONCLUSION

Larger retinal arteriolar caliber predicts incident retinopathy in children and adolescents with type 1 diabetes, independent of conventional risk factors for retinopathy. Measurement of retinal vascular caliber may provide prognostic information regarding the subsequent risk of diabetic retinopathy.

Prevalence of diabetes complications in adolescents with type 2 compared with type 1 diabetes

OBJECTIVE

To compare the prevalence of diabetes complications and their risk factors in youth with type 1 versus type 2 diabetes.

RESEARCH DESIGN AND METHODS

We performed a comparative clinic-based study of 1,433 patients with type 1 diabetes and 68 patients with type 2 diabetes aged <18 years from New South Wales, Australia. Retinopathy was assessed by seven-field stereoscopic retinal photography; albumin excretion rate from three consecutive, timed, overnight urine collections; peripheral neuropathy by thermal and vibration threshold; and autonomic neuropathy by pupillometry. HbA(1c) (A1C) and lipids were measured in all patients and C-peptide in patients with type 2 diabetes.

RESULTS

In patients with type 1 versus type 2 diabetes, median (interquartile range) age was 15.7 years (13.9-17.0) and 15.3 years (13.6-16.4), respectively (P = 0.2), whereas median diabetes duration was 6.8 years (4.7-9.6) and 1.3 years (0.6-3.1), respectively (P < 0.0001). Retinopathy was significantly more common in patients with type 1 diabetes (20 vs. 4%, P = 0.04), while microalbuminuria and hypertension were significantly less common (6 and 16% in type 1 diabetes vs. 28 and 36% in type 2 diabetes). Rates of peripheral and autonomic neuropathy were similar (27 and 61% in type 1 diabetes vs. 21 and 57% in type 2 diabetes). In multivariate analyses, microalbuminuria was significantly associated with older age (odds ratio 1.3 [95% CI 1.2-1.5], P < 0.001) and systolic hypertension (3.63 [2.0-6.3], P < 0.001) in type 1 diabetes, while only higher A1C (1.7 [1.3-2.9], P = 0.002) was significant in patients with type 2 diabetes.

CONCLUSIONS

Youth with type 2 diabetes have significantly higher rates of microalbuminuria and hypertension than their peers with type 1 diabetes, despite shorter diabetes duration and lower A1C. The results of this study support recommendations for early complications screening and aggressive targeting of glycemic control in patients with type 2 diabetes.

Complications of diabetes mellitus in childhood

Complications of diabetes include retinopathy, nephropathy, neuropathy, macrovascular disease, and associated autoimmune diseases. Clinical manifestations of complications uncommonly present in childhood and adolescence. Screening during the early years can identify subclinical disease and it offers an opportunity for early intervention. The Diabetes and Complications Control Trial has provided evidence for the long-term benefits of good glycemic control in preventing and delaying the onset of microvascular complications. Complications begin to manifest during adolescence, during which time all efforts should be made to educate and support young persons in achieving optimal diabetes control.

The association of aldose reductase gene (AKR1B1) polymorphisms with diabetic neuropathy in adolescents

AIMS

Variants in the aldose reductase gene (AKR1B1) have been implicated in the development of diabetic retinopathy and nephropathy, with the most convincing data identifying a (CA)(n) repeat microsatellite allele (Z-2), which has a functional role in gene expression. In this study the association between polymorphisms in the AKR1B1 gene and diabetic neuropathy was investigated.

METHODS

The pupillary response to light was used as the major outcome in this study along with abnormal hot thermal threshold. Three hundred and sixty-three adolescents underwent genotyping of the AKR1B1 gene. The microsatellite (CA)(n) repeat was sequenced and two single nucleotide polymorphisms, -106C-->T and -12C-->G, were investigated by restriction fragment length polymorphism.

RESULTS

Seventy-six percent of participants had pupillary abnormalities (45% with two, 15% with three abnormalities). Presence of the Z-2/Z-2 genotype increased the risk nearly three-fold for pupillary abnormalities [odds ratio (OR) 3.02, 95% confidence interval (CI) 1.14, 7.98). The susceptibility genotypes (Z-2/Z-2 with -106C/-106C, Z-2/Z with -106C/-106C or Z/Z with -106C/-106C) were associated with resting pupil diameter abnormalities when compared with the protective genotypes (Z+2/Z+2 or -106T/-106T) (OR 2.83, 95% CI 1.25, 6.41). The combination of Z+2/-106T reduced the risk of abnormal heat discrimination (OR 0.48, 95% CI 0.23, 0.99).

CONCLUSIONS

In this study we have shown that Z-2/Z-2 genotype is significantly associated with the development of pupillary abnormality, an early indicator of diabetic autonomic neuropathy, in adolescent Australian patients with Type 1 diabetes.

The role of autoimmunity at diagnosis of type 1 diabetes in the development of thyroid and celiac disease and microvascular complications

OBJECTIVE

The purpose of this study was to explore whether the presence of thyroid and endomysial autoantibodies at diagnosis of type 1 diabetes in children predicts development of thyroid and celiac disease, respectively, and whether diabetes-associated autoantibodies at diagnosis predict development of microvascular complications up to 13 years later.

RESEARCH DESIGN AND METHODS

Autoantibodies were measured at diagnosis of type 1 diabetes in 173 children aged 0-15 years and included thyroperoxidase antibody (TPOA), endomysial antibody (EMA), islet cell autoantibody, GAD antibody (GADA), and insulin autoantibody. Thyroid disease was defined as thyroid stimulating hormone level > or = 5 microU/ml. Celiac disease was confirmed by small-bowel biopsy. Assessment of microvascular complications included stereoscopic fundal photography, pupillometry, thermal threshold, and albumin excretion rate (AER).

RESULTS

The incidence rates for thyroid and celiac disease were 0.9 and 0.7 per 100 patient-years, respectively. Within 13 years, 6 of 13 children with positive TPOA tests at diagnosis developed thyroid disease compared with 5 of 139 children with negative TPOA tests (P < 0.001). All four patients with positive EMA titers at diagnosis had biopsy-proven celiac disease. Five of 11 patients who developed thyroid disease and 4 of 8 who developed celiac disease had negative TPOA and EMA tests at diagnosis, respectively. Retinopathy was detected in 39% and elevated AER in 36%. The presence of diabetes-associated autoantibodies at diagnosis did not predict microvascular complications though GADA titer levels predicted pupillary abnormality.

CONCLUSIONS

Elevated TPOA and EMA levels at diagnosis of type 1 diabetes predict the development of thyroid and celiac disease, respectively. In children with negative antibody titers at diagnosis, screening at 2-year intervals is recommended.

Discordant trends in microvascular complications in adolescents with type 1 diabetes from 1990 to 2002

OBJECTIVE

Since the Diabetes Control and Complications Trial, diabetes management goals have changed. The aims of the present study were to assess complication rates, including nerve abnormalities, in adolescents from 1990 to 2002 and to investigate associated risk factors.

RESEARCH DESIGN AND METHODS

Cross-sectional analysis of complications was assessed in three study periods (1990-1994 [T1], 1995-1998 [T2], and 1999-2002 [T3]) in adolescents matched for age and diabetes duration (n = 878, median age 14.6 years, median duration 7.5 years). Retinopathy was assessed by seven-field stereoscopic fundal photography, albumin excretion rate (AER) from three consecutive timed overnight urine collections, peripheral nerve function by thermal and vibration thresholds, and autonomic nerve function by cardiovascular reflexes.

RESULTS

Retinopathy declined significantly (T1, 49%; T2, 31%; and T3, 24%; P < 0.0001), early elevation of AER (> or = 7.5 microg/min) declined (38, 30, and 25%, respectively, P = 0.022), and microalbuminuria (AER > or = 20 microg/min) declined (7, 3, and 3%, respectively; P = 0.017, T1 vs. T2 and T3). Autonomic nerve abnormalities were unchanged (18, 21, and 18%, respectively; P = 0.60), but peripheral nerve abnormalities increased (12, 19, and 24%, respectively; P = 0.0017). More patients were treated with three or more injections per day (12, 46, and 67%, respectively; P < 0.0001) and insulin dose increased (1.08, 1.17, and 1.22 units x kg(-1) x day(-1), respectively; P < 0.0001), but median HbA(1c) (A1C) was unchanged (8.5, 8.5, and 8.4%, respectively). BMI and height SD score increased: BMI 0.46, 0.67, and 0.79, respectively (P < 0.0001), and height -0.09, 0.05, and 0.27, respectively (P < 0.0001).

CONCLUSIONS

Retinopathy and microalbuminuria declined over time in this cohort, but the increased rate of peripheral nerve abnormalities is of concern. Despite intensified management (higher insulin dose and more injections), A1C has not changed and remains well above the recommended targets for adolescents.

Prevalence of diabetes complications 6 years after diagnosis in an incident cohort of childhood diabetes

AIMS

To examine the prevalence of early diabetes complications 6 years after diagnosis of diabetes. The hypothesis that initial contact with a multidisciplinary team would be associated with a reduced risk of microvascular complications was tested in this cohort.

METHODS

Participants were recruited from an incident cohort of children aged < 15 years diagnosed between 1990 and 1992 in NSW, Australia. Initial management at a teaching hospital was documented at case notification. At 6 years, health care questionnaires and complications were assessed: retinopathy by 7-field stereoscopic retinal photography and elevated albumin excretion rate (AER) defined as the median of three overnight urine collections > or = 7.5 microg/min. Case attainment was 58% (209/361) with participants younger than non-participants and more likely living in an urban than rural location.

RESULTS

Retinopathy was present in 24%, median AER > or = 7.5 microg/min in 18%, and median AER > or = 20 microg/min in 2%. In multivariate analysis, initial management at a teaching hospital or consultation with all three allied health professionals combined with pubertal staging and cholesterol or HbA1c were all determinants of risk for retinopathy.

CONCLUSIONS

Early retinopathy and elevated AER are common in children 6 years after diagnosis. Initial allied health contact and management at a teaching hospital were associated with a reduced risk of microvascular complications in this cohort.

An ambulatory stabilisation program for children with newly diagnosed type 1 diabetes

OBJECTIVES

(i) To evaluate the benefits and adverse effects of a Diabetes Day Care Program (DDCP); and (ii) to compare outcomes in two cohorts diagnosed before and after implementing the DDCP ("pre-DDCP" and "post-DDCP").

DESIGN

Outcomes from the pre-DDCP cohort were compared with those of the post-DDCP cohort.

SETTING

The study was conducted from March 2001 to October 2002 at the Children's Hospital at Westmead.

PARTICIPANTS

The pre-DDCP cohort comprised all children newly diagnosed with type 1 diabetes from March 2000 to November 2000 (n = 49). The post-DDCP cohort were those diagnosed from November 2000 to August 2001 (n = 61).

MAIN OUTCOME MEASURES

Length of stay, adverse events, insulin requirement and glycohaemoglobin (HbA(1c)) level over the first year after diagnosis were ascertained from medical records. Questionnaires to measure parents' knowledge of diabetes, emotional adjustment to diabetes, and responsibility for and conflict over specific diabetes management tasks were completed by parents at 6-monthly intervals.

RESULTS

Median length of hospital stay decreased from 5.14 days (range, 2-10) to 1.70 days (range, 0-10) (P < 0.001). There were no differences between the two cohorts in insulin requirement at 12 months (pre-DDCP: 0.9 U/kg [95% CI, 0.8-1.0]; post-DDCP: 0.8 U/kg [95% CI, 0.7-0.9]; P = 0.22), HbA(1c) level at 12 months (pre-DDCP: 8.4% [95% CI, 8.0%-8.9%]; post-DDCP: 8.2% [95% CI, 7.9%-8.5%]; P = 0.37) and adverse events over the first year after diagnosis. Both groups reported similar scores for the parental questionnaires.

CONCLUSIONS

Ambulatory stabilisation of children with type 1 diabetes provides similar metabolic outcomes for the child, and comparable levels of diabetes knowledge and similar psychosocial outcomes for the family, to inpatient stabilisation programs.

Safety of the newer inhaled corticosteroids in childhood asthma

Inhaled corticosteroids (ICS) remain a vital part of the management of persistent asthma, but concerns have been raised about their potential adverse effects in children. This review examines the safety data on three new ICS - fluticasone propionate, mometasone, and extrafine beclomethasone in hydrofluoroalkane (HFA-134a) propellant (QVAR The use of tradenames is for product identification purposes only and does not imply endorsement. formulation) in relation to the older corticosteroids. Topical adverse effects such as thrush and dysphonia are rare, but dental erosion is a possibility with powder forms of ICS because of their low pH. Thus, it is important to stress mouth rinsing after administration and maintaining good dental hygiene to minimize this risk. Biochemical adrenal suppression can be readily demonstrated, particularly with high doses of all ICS. The clinical relevance of this was uncertain in the past, but there have now been >50 reported cases of acute adrenal crises in children receiving ICS, most of whom were on fluticasone propionate. In order to minimize the risk of symptomatic adrenal suppression, it is important to back-titrate the ICS dose and alert families of children receiving high-dose ICS of this potential adverse effect. A pediatric endocrine opinion should be sought if adrenal suppression is suspected. The older ICS cause temporary slowing of growth velocity, but the limited data available do not show any significant compromise of final adult height. The effect on growth of fluticasone propionate may not be as great as with the older ICS, but the studies have been short term and only used low doses of fluticasone propionate. There have been case reports of growth suppression in children receiving high doses of fluticasone propionate. The limited studies performed on the effect of ICS on bone mineral density in children did not show any adverse effects, but there may be an increased risk of fractures. Hydrofluoroalkane beclomethasone (QVAR) is essentially the same drug as chlorofluorocarbon beclomethasone, but with double the lung deposition owing to the smaller particle size. Thus, it could be expected that any adverse effects seen with chlorofluorocarbon beclomethasone would be the same with hydrofluoroalkane beclomethasone. However, some of the published data, particularly in adults, suggest that hydrofluoroalkane beclomethasone may be less systemically active than chlorofluorocarbon beclomethasone, even at equipotent doses. As yet, there are no long-term data on mometasone, but initial studies in adults suggest there may be less suppression of the hypothalamic-pituitary-adrenal axis, although further studies are required, particularly in children.ICS will remain a cornerstone in the management of persistent pediatric asthma, provided that the diagnosis of asthma is secure. It is very important to use ICS appropriately and to ensure the lowest possible doses are used to achieve symptom control, thus minimizing the risk of serious adverse effects.

Intramyocellular lipid, adiposity, and muscle oxygen supply in prepubertal type 1 diabetes

BACKGROUND

In the non-diabetic population, intramyocellular lipid (IMCL) accumulation is associated with obesity and poor muscle oxygen supply. IMCL levels are increased in type 1 diabetes, but their significance is less clear.

METHODS

We studied a group of 16 prepubertal boys (age 6.4-9.9 yr) with type 1 diabetes and a range of glycemic control [hemoglobin A1c (HbA1c) 6.4-10.2%]. Children's adiposity was assessed by anthropometry, muscle oxygen supply by near-infrared spectroscopy (NIRS), abdominal and IMCL content by magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS).

RESULTS

IMCL content did not associate with muscle reoxygenation rate, abdominal adiposity, duration of diabetes, or recent glycemic control. Muscle reoxygenation rate correlated with percentage body fatness (r2 = 0.46, p = 0.004), visceral (r2 = 0.45, p = 0.007) and abdominal subcutaneous fat volume (r2 = 0.63, p = 0.0004), and dietary fat intake (r2 = 0.27, p = 0.03) but not with the duration of diabetes nor HbA1c. HbA1c was significantly related to dietary fat intake only (r2 = 0.28, p = 0.03).

CONCLUSION

While causality cannot be inferred, interventions aimed at improving muscle oxygen supply, or preventing its deterioration, might reduce the development of adiposity in children with type 1 diabetes.

High plantar pressure and callus in diabetic adolescents. Incidence and treatment

This study examined the incidence of high peak plantar pressure and plantar callus in 211 adolescents with diabetes mellitus and 57 nondiabetic controls. The percentage of subjects with these anomalies was the same in both groups. Although diabetic subjects were no more likely than nondiabetic controls to have high peak plantar pressure and callus, these anomalies place individuals with diabetes at greater risk of future foot problems. The effects of orthoses, cushioning, and both in combination were monitored in 17 diabetic subjects with high peak plantar pressure and in 17 diabetic subjects with plantar callus; reductions of up to 63% were achieved. Twelve-month follow-up of diabetic subjects fitted with orthoses showed a significant reduction in peak plantar pressure even when the orthoses were removed. The diabetic subjects who had not received any interventions during the same 12-month period showed no significant change in peak plantar pressure.

Do all prepubertal years of diabetes duration contribute equally to diabetes complications?

OBJECTIVE

This study was designed to explore the timeline of protection against complications in prepubertal children with diabetes, in particular the effects of diabetes duration before age 5 years.

RESEARCH DESIGN AND METHODS

In this study, 193 adolescents with prepubertal diabetes onset were followed longitudinally for retinopathy (early background and clinical) and microalbuminuria (albumin excretion rate >7.5 micro g/min and >20 micro g/min). Multiple logistic regression analysis was used to compare the effect of pre- and postpubertal diabetes duration on the risk of each complication in 90 subjects reassessed as young adults. For the entire cohort, Kaplan-Meier estimates were used to determine time free of each complication, and survival was compared in those diagnosed before and after age 5 years. Accelerated failure time modeling was used to estimate the effect of covariates, including diabetes duration before puberty, on the risk of complications.

RESULTS

Prepubertal duration improved the prediction for retinopathy over postpubertal duration alone in the young adults. The survival-free period of retinopathy and microalbuminuria was significantly longer (2-4 years) for those diagnosed before age 5 years compared with those diagnosed after age 5 years. Time to onset of all complications increased progressively with longer diabetes duration before gonadarche. Higher HbA(1c) during adolescence had an independent effect on the risk of retinopathy and microalbuminuria.

CONCLUSIONS

Prepubertal diabetes duration remains a significant predictor of retinopathy in young adults. The effect of time on the risk of retinopathy and microalbuminuria is nonuniform, with an increasing delay in the onset of complications in those with longer prepubertal duration. These findings are of major clinical importance when setting targets of glycemic control in young children who are at greatest risk of hypoglycemia.

Adrenal crises in children treated with high-dose inhaled corticosteroids for asthma

Three children presented with adrenal crises, manifested by vomiting and hypoglycaemia, after protracted courses of high-dose inhaled corticosteroids for asthma. Significant dose reduction was possible in all three without loss of asthma control, emphasising the importance of back-titration to minimise dose. Parents of children taking high doses of inhaled corticosteroids should be alerted to the clinical features of adrenal insufficiency. If suspected, prompt medical assessment should be arranged, including serum glucose and cortisol measurement.

Secular trends in growth in diabetes: are we winning?

AIM

To determine potential effects of modern treatment on growth in diabetic children.

METHODS

Retrospective analysis of growth in diabetic children stratified by their year of diagnosis between 1974 and 1995. A total of 451 children and adolescents attending the Diabetes Outpatient and Outreach Clinics of Royal Alexandra Hospital for Children in Sydney and rural NSW, Australia were studied. Standard deviation scores (SDS) for height and body mass index (BMI) were assessed at diagnosis, five years later (n = 451), and 10 years later (n = 111).

RESULTS

After five years of diabetes duration height SDS loss correlated with higher HbA(1c) and fewer injections. BMI SDS gain correlated with HbA(1c) and age at diagnosis. Although there was no significant difference in their height SDS or age at diagnosis, children diagnosed 1974-90 were significantly shorter than children diagnosed 1991-95 (height SDS 0.07 v 0.37) after five years diabetes duration. Furthermore, over 5 and 10 years, the 1979-90 group had lost significant height SDS (mean change -0.20 at 5 years, -0.29 at 10 years); this did not occur in the 1991-95 group (-0.01 at 5 years, -0.13 at 10 years). The BMI SDS increased significantly after 10 years in the 1974-90 group (mean change 0.37) but not in the 1991-95 group. There was no significant difference in the 174 females' age of menarche (13.0 v 12.8 years).

CONCLUSIONS

Children with diabetes treated with modern regimens maintain their increased height from diagnosis better, and after five years diabetes duration, were taller than children diagnosed before 1991.

Ultrasonography of plantar soft tissues thickness in young people with diabetes

AIMS

The aims of this study were to examine soft tissue changes in the skin and plantar aponeurosis of young people with Type 1 diabetes mellitus (T1DM) and to evaluate any relationship between any soft tissue changes, arch length, limited joint mobility (LJM) and plantar pressure.

METHODS

The thickness of the skin on the plantar surface of the foot and plantar aponeurosis were examined using ultrasound in 216 young people with diabetes and 57 controls. Foot length, arch length, joint mobility, peak pressure and pressure time integrals were evaluated.

RESULTS

Skin was not significantly thicker in the diabetic subjects. The plantar aponeurosis was significantly thicker in the diabetic subjects and was associated with foot size, male gender and subtalar joint (ST) LJM (P < 0.01). Males were nearly three times more likely to have thickened plantar aponeurosis.

CONCLUSION

Soft tissue thickening in young people with T1DM affects the deeper structures on the plantar surface of the foot rather than the skin. Thickening of the plantar aponeurosis was associated with LJM at the ST joint and male gender, but was not associated with plantar pressure or arch height changes. Plantar aponeurosis thickening does not appear to alter foot mechanics in young people with T1DM.

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.

Predictors of glycaemic control and hypoglycaemia in children and adolescents with type 1 diabetes from NSW and the ACT

OBJECTIVES

To audit glycaemic control and incidence of severe hypoglycaemia in children and adolescents with type 1 diabetes in New South Wales (NSW) and the Australian Capital Territory (ACT).

DESIGN

A multicentre, population-based, cross-sectional study from 1 September to 31 December, 1999.

PARTICIPANTS

1190 children and adolescents aged 1.2-15.8 years with type 1 diabetes, identified from three hospital-based paediatric diabetes units, four private city-based paediatric practices and 18 regional outreach clinics in NSW and the ACT.

MAIN OUTCOME MEASURES

HbA(1c) level and incidence of severe hypoglycaemia (defined by unconsciousness or seizures).

RESULTS

The response rate was 67% (1190 of a target group of 1765). The median HbA(1c) level was 8.2% (interquartile range, 7.6%-9.1%). Significant predictors of HbA1c level in a multiple regression model were duration (b = 0.05; 95% CI, 0.02-0.07) and insulin dose/kg (b = 0.46; 95% CI, 0.27-0.66). At least one episode of severe hypoglycaemia in the previous three months was reported in 6.7%, and the rate of severe hypoglycaemia was 36/100 patient-years. Significant predictors of hypoglycaemia in a Poisson regression model were younger age (P = 0.03), male sex (P = 0.04), longer diabetes duration (P = 0.02), and > 3 daily insulin injections (P = 0.02), but not HbA(1c) level. Children with diabetes had higher BMI standard deviation scores compared with population standards, and those in the highest quartile of BMI standard deviation score were younger, had shorter diabetes duration and had higher HbA(1c) level.

CONCLUSIONS

Many children and adolescents with type 1 diabetes have suboptimal glycaemic control, placing them at high risk of developing microvascular complications. Those with longer diabetes duration are at increased risk of suboptimal glycaemic control and severe hypoglycaemia and should be targeted for interventional strategies.

Metabolic correlates with obstructive sleep apnea in obese subjects

OBJECTIVE

To examine links between obstructive sleep apnea (OSA), insulin resistance, and dyslipidemia.

STUDY DESIGN

Obese (body mass index [BMI] >95th percentile for age and gender) children who snored (n = 62, 46 males, age 10.89 [5-16 years] underwent polysomnography and metabolic studies.

RESULTS

Respiratory disturbance index (RDI) was 9.23 (0-95), with 23 children (39%) recommended for treatment. Fasting insulin levels were 154.6 pmol/L +/- 79.8 (52-486), and fasting glucose levels were high in 7 children (11%). Fasting insulin levels correlated with sleep variables, including log transformed RDI (log(10)RDI) (P =.01), desaturation events (P =.05), arousal index (P =.01), and sleep-time with oxygen saturation in arterial blood <90% (P =.03) (adjusted r (2) = 0.21, F = 3.9, P =.005), but not with age, or BMI Z score. Log(10)RDI correlated with fasting insulin (P =.001) and BMI Z score (P =.03) (adjusted r (2) = 0.12, F = 3.9, P =.005), but not age or other metabolic variables. The correlation between log(10)RDI and fasting insulin persisted in models combining sleep and metabolic variables: log(10)RDI, adjusted r (2) = 0.75, F = 35.2, P <.001, and for fasting insulin, adjusted r (2) = 0.42, F = 6.1, and P <.001.

CONCLUSIONS

The severity of OSA (log(10)RDI) correlated with fasting insulin levels, independent of BMI. Insulin levels may be further elevated as a consequence of OSA in obese children.

Paraoxonase gene cluster is a genetic marker for early microvascular complications in type 1 diabetes

BACKGROUND

Paraoxonase is a serum enzyme, which prevents oxidation of low-density lipoprotein (LDL) by hydrolyzing lipid peroxides. Two polymorphisms in PON1 gene have been associated with cardiovascular and microvascular diseases in both diabetic and non-diabetic patients.

AIMS

The current project was designed to investigate the association between the polymorphisms of two PON genes and diabetes microvascular diseases (retinopathy and microalbuminuria) and any potential linkage between Met54Leu of PON1 and Cys311Ser of PON2 gene.

METHODS

Diabetic retinopathy and albumin excretion rate were assessed in 372 adolescents with Type 1 diabetes who were genotyped for the two polymorphisms.

RESULTS

We confirmed the increased susceptibility for diabetic retinopathy for the Leu/Leu genotype (odds ratio (OR) 3.34 (confidence interval (CI) 1.95, 5.75), P < 0.0001). The Ser/Ser genotype was significantly more common in those patients with microalbuminuria (albumin excretion rate > or = 20 microg/min) compared with those with albumin excretion rate < 20 microg/min (OR 4.72 (CI 2.65, 8.41), P < 0.0001). The Ser311 of PON2 was in strong linkage disequilibrium with Leu54 of PON1 gene (Delta = 23 x 10(4), P < 0.001). The delta value was higher for those without complications (28 x 104, P < 0.001) compared with those with complications (15.5 x 10(4), P < 0.001).

CONCLUSIONS

This study supports the hypothesis that diabetic microangiopathy is genetically heterogeneous. PON1 Leu/Leu increases the risk for retinopathy and PON2 Ser/Ser increases the risk for microalbuminuria.

Comparison of Dinamap 8100 with sphygmomanometer blood pressure measurement in a prepubertal diabetes cohort

OBJECTIVE

To compare the conventional sphygmomanometer with the semiautomated Dinamap 8100 (Critikon, Tampa, FL, USA) for the measurement of blood pressure in prepubertal children with insulin-dependent diabetes mellitus.

METHODOLOGY

Blood pressure was measured using both methods in 61 prepubertal children (aged 8-13 years) on 189 occasions over 4 years. The measurements were compared using the Bland-Altman plot. Tracking correlations of blood pressure centiles over time were analyzed by the general estimating equation.

RESULTS

Accuracy criteria of the Association for the Advancement of Medical Instrumentation were met and a British Hypertensive Society 'B' grading was reached. Differences in systolic and diastolic blood pressure were found between the two methods (P < 0.01). For systolic blood pressure, common correlations were 0.54 (Dinamap) and 0.51 (sphygmomanometer) and for diastolic blood pressure were 0.33 and 0.42, respectively.

CONCLUSION

The Dinamap 8100 is an acceptable alternative in clinic practice and research for prepubertal children.

Autonomic neuropathy: diagnosis and impact on health in adolescents with diabetes

Symptomatic autonomic neuropathy and abnormal cardiovascular autonomic tests are associated with increased mortality due to vascular disease and increased risk of sudden deaths. Intensive therapy in the DCCT caused a significant risk reduction of developing autonomic nerve abnormalities at five years only in the Primary Prevention Group (4 vs. 9%). At the Royal Alexandra Hospital for Children, the prevalence of cardiovascular reflex abnormalities is 28%. Over 5 years, we have found no increase in the rate of single cardiovascular abnormalities and a low rate of persistence. Two or more abnormalities developed in 5%. Repeated measures of pupillary function showed a significant increase in abnormalities and a higher level of persistently abnormal tests. Spectral analysis and 24-hour BP monitoring may detect autonomic dysfunction at earlier stages but longitudinal studies are not yet available.

Macroangiopathy--does it play a role in young people?

Using a novel ultrasound method, brachial artery endothelial and smooth muscle physiology were studied in 20 adolescents with IDDM and in 20 nondiabetic subjects matched for age (13-22 years), gender and vessel size. Endothelium-dependent dilatation (EDD) was assessed in response to flow (EDD) and endothelium-independent vasodilatation after sublingual glyceryl trinitrate (GTN). Both EDD and GTN were reduced in those with IDDM compared with controls: 5 vs. 9%, (p = 0.0002) and 14 vs. 21% (p = 0.002). Abnormal EDD was found in 12 IDDM adolescents (diabetes duration 3.3-14.9 years). The mean urinary albumin excretion rate of the diabetic group with abnormal EDD was 5.76 +/- 2.82 vs. 8.05 +/- 4.88 microg/min in those with normal EDD (p = 0.25). In the diabetic adolescents there was no significant correlation observed between the test for early large vessel disease, HbAlc and tests for diabetic microangiopathy.

Beneficial effects of increasing monounsaturated fat intake in adolescents with type 1 diabetes

This study aimed to increase the monounsaturated fat content in the diet of outpatient adolescents with type 1 diabetes and to examine the metabolic effects after 12 weeks. Twenty-three adolescents were randomly allocated to either a high monounsaturated fat diet or a control diet. Their mean age was 16.9 (S.D. 2.1) years and median HbA(1c) was 9.1% [IQR 7.9-10.4%]. Dietary targets were not reached judged by their 4-day food diaries. However, the whole study group had a significant increase in monounsaturated fat as indexed by red cell phospholipid fatty acids (RCFAs), with an increase of n-9 RCFAs from 14.9% [IQR: 14.5-21.7%] to 21.7% [IQR: 18.8-25.6%] (P=0.002). Changes in n-9 RCFAs were inversely related to changes in HbA(1c) (R(2)=0.26, P=0.02), such that a 10% increase in n-9 RCFAs corresponded to a 0.64% improvement (decrease) in HbA(1c). Changes in n-9 RCFAs were also inversely related to changes in plasma total cholesterol (R(2)=0.38, P=0.002) and plasma LDL cholesterol (R(2)=0. 21, P=0.03). These changes were not associated with changes in insulin dose, body weight or physical activity. Overall, the results demonstrate that a modest increase in the monounsaturated fat content of an adolescent diet has the potential to improve glycaemic control and lipid profile.

Diabetes complication screening in 937 children and adolescents

Results are presented of diabetes complication screening in children and adolescents aged 6-20 years. Their diabetes duration was 0.02-18.4 yr and median HbA1c over the preceding 36 months was 8.4% [IQR 7.8-9.3]. Gradable retinal photographs were obtained in 937: 110 less than 11 years (< 11 yr Gp). Albumin excretion rate (AER) was obtained from 3 timed overnight urine collections in 691: 100 in < 11 yr Gp. Early retinopathy was found in 27% (9% in < 11 yr Gp). Microalbuminuria (AER > or = 20 micrograms/min) was found in 4%. Significant individual risk factors for both complications were higher blood pressure, cholesterol, HbA1c, pubertal staging, older age and longer diabetes duration. Using multiple logistic regression, significant risk factors for retinopathy were longer duration and older age and in addition higher HbA1c. Diabetes complication screening detected early subclinical disease in children and adolescents who may benefit from lowering blood pressure and improving metabolic control. Screening should commence after five years of duration in young children, and after two years of duration in adolescents.

Limited joint mobility in the hands and feet of adolescents with Type 1 diabetes mellitus

AIMS

Limited joint mobility (LJM) in the foot has not been assessed in adolescents with Type 1 diabetes mellitus (DM) but is associated with neuropathic ulceration in adults. This study was designed to determine the presence of LJM in adolescents with Type 1 DM and its association with microvascular disease.

METHODS

The hands, feet and hips were examined in 302 diabetic adolescents and 51 nondiabetic controls (aged 11.5-20 years). LJM was defined as less than the fifth percent reference for controls.

RESULTS

Reduced motion was found in 35% of diabetic adolescents at the subtalar (ST) joint, 18% at the first metatarsophalangeal (MTP) joint, 26% at the fifth metacarpophalangeal (MCP) joint and 13% had limited passive extension of the interphalangeal (IP) joints of the hands. Limited passive IP joint extension of the hands was not present in the controls. Limited active IP joint extension, a positive 'prayer sign', occurred in 35% of diabetic adolescents and 14% of controls. Diabetic adolescents showing LJM in any of these areas, except the prayer sign, were more likely to have retinopathy (odds ratio 2.53, CI: 1.53-4.18). Those with LJM in the foot were more likely to have albumin excretion rates >7.5 microg/min (OR 2.06, CI: 1.16-3.68).

CONCLUSION

LJM in the feet of adolescents with Type 1 DM is associated with microvascular disease and is a useful routine clinical measure.

Diabetes microvascular complications in prepubertal children

These are the baseline findings of a group of 68 prepubertal children enrolled in a longitudinal study of the development of early diabetes microvascular complications prior to gonadarche. The median age of the children was 9.8 years, the median diabetes duration 3.6 years and the mean HbA1c 8.4%. Mild nonproliferative retinopathy was present in 6 of 67 (9%) children, assessed by 7-field stereoscopic fundus photography. Those with retinopathy had higher total cholesterol (p < 0.05) and lower DHEAS (p < 0.01). Albumin excretion rate (AER) was calculated as the mean of three overnight consecutive urine collections. AER > 7.5 micrograms/min was present in 5 of 64 (8%), and one boy had a mean AER > 15 micrograms/min. Those with AER > 7.5 micrograms/min had higher diastolic blood pressure and diastolic blood pressure percentiles (p < 0.05). Longitudinal study of this cohort will establish which factors in the prepubertal years are important for the development of diabetes microvascular complications.

Large vessel dysfunction in diabetic adolescents and its relationship to small vessel complications

Endothelial dysfunction is considered a key early event in atherosclerosis. Using a novel ultrasound method, brachial artery endothelial and smooth muscle physiology were studied in 20 adolescents with IDDM and compared to that in 20 nondiabetic subjects matched for age (13-22 years), gender and vessel size. Endothelium-dependent dilatation (EDD) was assessed in response to flow (EDD) and endothelium-independent vasodilatation after sublingual glyceryl trinitrate (GTN). Both EDD and GTN were reduced in those with IDDM compared with controls: 5% vs 9%, (p = 0.0002) and 14% vs 21% (p = 0.002). Abnormal EDD was found in 12 IDDM adolescents (diabetes duration 3.3-14.9 years). The maximum albumin excretion rate of the diabetic group was 17 micrograms/min. Four adolescents had retinopathy assessed by stereoscopic fundus photography. Three had at least one of four cardiovascular autonomic test abnormalities. There was no significant correlation observed between the test for early large vessel disease and those for diabetic microangiopathy. Large vessel dysfunction was the most common abnormality.

Progression of borderline increases in albuminuria in adolescents with insulin-dependent diabetes mellitus

We aimed to determine the natural history of borderline increases in albuminuria in adolescents with insulin-dependent (Type 1) diabetes mellitus (IDDM) and factors which are associated with progression to persistent microalbuminura. Fifty-five normotensive adolescents with IDDM and intermittent microalbuminura (overnight albumin excretion ratte of 20-200 micrograms min-1 on one of three consecutive timed collections, n = 29) or borderline albuminura (mean overnight albumin excretion rate of 7.2-20 micrograms min-1 on one of three consecutive timed collections, n = 30) were followed prospectively at 3 monthly intervals. The endpoint was persistent microalbuminuria defined as a minimum of three of four consecutive overnight albumin excretion rates of greater than 20 micrograms min-1. One hundred and forty-two adolescents with IDDM and normoalbuminura were also followed prospectively. Fifteen of the 59 patients (25.4%) with intermittent (9/29) or borderline (6/30) albuminura progressed to persistent microalbuminura (progressors) over 28 (15-50) months [median (range)] in comparison with two of the 142 patients with normoalbuminuria at entry (relative risk = 12.6; p = 0.001). Progressors to persistent microalbuminura were pubertal and had higher systolic (p = 0.02) and diastolic (p = 0.02) blood pressure, and HbA1c (p = 0.004) than non-progressors. All patients remained normotensive. Glomerular filtration rate, apolipoproteins, dietary phosphorus, protein and sodium intakes, and prevalence of smoking did not differ between progressors and non-progressors. Total renin was higher in the diabetic patients without a difference between progressors and non-progressors. In conclusion there is a relatively high rate of progression to persistent microalbuminuria in pubertal adolescents with borderline increases in albuminura and duration greater than 3 years. These patients require attention to minimize associated factors of poor metabolic control and higher blood pressure in the development of incipient nephropathy.

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.

Vascular responses by transcutaneous oximetry in adolescents with and without diabetes

The vascular response of the skin was evaluated by transcutaneous oximetry (TcPO2) in the forearm in 119 adolescents with type I diabetes aged 10.4-19.8 (median 15.3) years, with a duration of diabetes 0.7 to 18.3 (median 7.8) years, and 49 nondiabetic adolescents aged 11.3-18.8 (median 15.5) years. Two different vascular stimuli were used: heating of the probe to 43 degrees C and 5 min of ischemia. Baseline TcPO2 after 13 min of equilibration at a probe temperature of 43 degrees C, postischemic maximum TcPO2, and the postischemic TcPO2 increase were significantly lower in the diabetic group compared to the control group (p = 0.0001, p < 0.0001, and p = 0.0001, respectively). In both the diabetic and the control groups, gender differences were found for baseline TcPO2 (p = 0.0001 and p = 0.0009, respectively) and postischemic maximum TcPO2 (p = 0.0001 and p = 0.005, respectively), the girls having consistently higher values. After controlling for gender by multiple linear regression analysis, duration of diabetes showed a significant effect on postischemic maximum TcPO2 (R2 = 22%, p = 0.02). The postischemic TcPO2 increase was not affected by gender. Lower values for the postischemic TcPO2 increase were related to higher GHb values (R2 = 4%, p = 0.03). Abnormal values for oximetry were associated only with some autonomic nerve function abnormalities. Differences in the vascular response to heat and ischemia as measured by transcutaneous oximetry can be demonstrated between adolescents with type I diabetes and nondiabetic controls, as well as between girls and boys. Lower values in diabetic subjects are weakly associated with diabetes duration and metabolic control, independent of gender.

Prospective assessment of autonomic and peripheral nerve function in adolescents with diabetes

Autonomic and peripheral nerve function were studied prospectively in 102 adolescents with Type 1 diabetes over a 5-year period. All adolescents were assessed three times; 54 were assessed four times. The median age at baseline was 14.5 (range 10.4-18.0) yr. The median diabetes duration at baseline was 6.8 (range 1.3-15.2) yr. Autonomic nerve function was assessed by measuring heart rate variation during deep breathing, valsalva manoeuvre, standing from a lying position (30/15 ratio), and the postural change in systolic blood pressure. Peripheral nerve function was assessed by determining the thermal threshold for heat and cold at the wrist and foot and the vibration threshold at the great toe and medial malleolus. At baseline, 29.5% adolescents had at least one abnormal autonomic nerve test and 28.4% had at least one abnormal peripheral nerve test. There was no significant increase in the number of abnormalities over the study period. Persisting abnormalities were present in only six individuals. Abnormalities were not related to age, diabetes duration or glycaemic control. In summary, a low rate of neurological abnormalities was found, suggesting that more than 3 years of follow-up is required to detect evolving neuropathy in this age group.

Development and progression of diabetic retinopathy: adolescents at risk

The aims of this study were to evaluate short-term changes in retinopathy in adolescents, and to examine the relationship of these changes to risk factors. Two-hundred and three adolescents, with a median age of 14.5 (range 10.4 to 20.6) yr and a median duration of diabetes of 6.6 (1.1 to 16.3) yr, were included in the study. Retinopathy was assessed on two occasions, using stereoscopic fundus photography; the median time between assessment was 1.3 (0.5 to 3.0) yr. At baseline, 41% of the adolescents had background retinopathy. When patients were stratified according to the median diabetes duration (DD) (6.6 yr) and glycaemic control over the 12 months prior to assessment (HbA1C) (8.4%), the percentage of retinopathy in each group was: lowDD/lowHbA1C 13%; lowDD/highHbA1C 40%; highDD/lowHbA1C 42%; and highDD/highHbA1C 72%. Using a 2-step criteria for stability or change in retinopathy, 11% of the 203 adolescents showed progression of retinopathy, 41% had stable retinopathy, 5% showed regression, and 43% had no retinopathy at either assessment. Change in retinopathy was related to age at baseline assessment (borderline significance, p = 0.06), diabetes duration (p < 0.001), glycaemic control (p < 0.001) and total cholesterol (p = 0.04), and was also related to DD/HbA1C group membership (chi 2, p < 0.001). This study highlights the combined adverse effect of long diabetes duration and poor glycaemic control on the development and progression of retinopathy during adolescence, and identifies a group that is likely to show progression over a relatively short period.

The prospective assessment of autonomic nerve function by pupillometry in adolescents with type 1 diabetes mellitus

The study aimed to compare the longitudinal assessment of automatic nerve function by computerized infrared pupillometry and standard cardiovascular tests in adolescents with diabetes. Adolescents (n = 150) were assessed at two time points (T1 and T2). The median time interval between assessments was 1.5 (range 0.9-3) years. At T1 the median age was 14.5 (range 8.3-19.5) years and the median duration was 6.5 (range 1.1-16) years. The pupillary variables assessed included the resting pupil diameter, the maximum constriction velocity, and the reflex amplitude of constriction. Heart rate reflexes were assessed in response to deep breathing, the Valsalva manoeuvre, and on standing from a lying position (30/15 ratio). Between visits there was a significant decrease in maximum constriction velocity (6.0 mm s-1 vs 6.3 mm s-1, p = 0.0001) and resting pupil diameter (6.2 mm vs 6.3 mm, p = 0.001). At reassessment pupillary abnormalities increased from 32 (21%) to 45 (30%), with 17 (54%) of the initial abnormalities persisting. Adolescents with abnormally slow maximum constriction velocity compared to those with normal maximum constriction velocity had a higher glycated haemoglobin (HbA1c%) at T2 (p = 0.02) and between assessments (p = 0.01). Cardiovascular test abnormalities did not increase between visits and the persistence of initial abnormalities was low (21%). In summary, pupillometry appears a more sensitive test of automatic nerve dysfunction in adolescents with diabetes than assessment of cardiovascular reflexes.

Cholestatic jaundice and congenital hypopituitarism

OBJECTIVE

The prevalence of cholestatic jaundice as a presenting feature of congenital hypopituitarism is assessed.

METHODOLOGY

A retrospective case record analysis of the presenting features in all patients diagnosed as having congenital hypopituitarism between 1973-93.

RESULTS

Seven of the 20 patients with congenital hypopituitarism presented with cholestatic jaundice as the major initial manifestation of the disorder. Liver biopsy findings in three revealed intracellular bile pigment accumulation and variable giant cell formation.

CONCLUSION

Cholestatic jaundice was the major manifestation of congenital hypopituitarism in 35% of patients presenting in the neonatal or early infancy period.