Urinary albumin/creatinine ratio tertiles predict risk of diabetic retinopathy progression: a natural history study from the Adolescent Cardio-Renal Intervention Trial (AdDIT) observational cohort.

AIMS/HYPOTHESIS: We hypothesised that adolescents with type 1 diabetes with a urinary albumin/creatinine ratio (ACR) in the upper tertile of the normal range (high ACR) are at greater risk of three-step diabetic retinopathy progression (3DR) independent of glycaemic control. METHODS: This was a prospective observational study in 710 normoalbuminuric adolescents with type 1 diabetes from the non-intervention cohorts of the Adolescent Cardio-Renal Intervention Trial (AdDIT). Participants were classified as 'high ACR' or 'low ACR' (lowest and middle ACR tertiles) using baseline standardised log10 ACR. The primary outcome, 3DR, was determined from centrally graded, standardised two-field retinal photographs. 3DR risk was determined using multivariable Cox regression for the effect of high ACR, with HbA1c, BP, LDL-cholesterol and BMI as covariates; diabetes duration was the time-dependent variable. RESULTS: At baseline mean ± SD age was 14.3 ± 1.6 years and mean ± SD diabetes duration was 7.2 ± 3.3 years. After a median of 3.2 years, 83/710 (12%) had developed 3DR. In multivariable analysis, high ACR (HR 2.1 [1.3, 3.3], p=0.001), higher mean IFCC HbA1c (HR 1.03 [1.01, 1.04], p=0.001) and higher baseline diastolic BP SD score (HR 1.43 [1.08, 1.89], p=0.01) were independently associated with 3DR risk. CONCLUSIONS/INTERPRETATION: High ACR is associated with greater risk of 3DR in adolescents, providing a target for future intervention studies. TRIAL REGISTRATION: isrctn.org ISRCTN91419926.

Baseline extended zone retinal vascular calibres associate with sensory nerve abnormalities in adolescents with type 1 diabetes: A prospective longitudinal study.

OBJECTIVE: The relationship between retinal vascular calibres (RVCs) and diabetic neuropathy is unclear. We investigated associations between RVCs and sensory nerve abnormality in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: In a prospective longitudinal study of 889 adolescents with type 1 diabetes with baseline mean (±SD) age 14.1 ± 1.5 years and HbA1c IFCC 69.4 ± 14.1 mmol/mol (8.6 ± 1.3%), RVCs were assessed from baseline retinal photographs: 'central zone' calibres, summarized as central retinal arteriolar (CRAE) and venular equivalents (CRVE) and 'extended zone' calibres: mean width of arterioles (MWa) and venules (MWv). Sensory nerve abnormality was defined as at least one abnormal sensory quantitative testing from two thermal and two vibration threshold tests measured at foot every 1-2 years. Associations between baseline RVC and sensory nerve function were examined using generalized estimating equations and cumulative risk by Cox regression analyses. RESULTS: During a median study follow-up of 6.2 [IQR 3.7-10.4] years, sensory nerve abnormality was found in 27% of adolescents. Narrower extended zone calibre quartiles but not CRAE or CRVE quartiles were independently associated with sensory nerve abnormality: MWa (Q1 vs. Q2-4: OR 1.35 (95% CI 1.02, 1.61) and MWv (Q1 vs. Q2-4: 1.31 (1.03, 1.7)), after adjusting for HbA1c , duration and blood pressure. Similarly, in Cox regression, the narrowest quartiles were associated with sensory nerve abnormality: MWa hazard ratio (HR) 1.5 (1.3, 1.8) and MWv 1.6 (1.4, 1.9). CONCLUSIONS: Narrower extended zone retinal calibres were associated with sensory nerve abnormality in adolescents with type 1 diabetes and may present useful biomarkers to understand the pathophysiology of neuropathy.

Type 2 diabetes in children and adolescents across Australia and New Zealand: A 6-year audit from The Australasian Diabetes Data Network (ADDN).

OBJECTIVES: To assess the clinical and demographic characteristics of children and adolescents across Australia and New Zealand (NZ) with type 2 diabetes. METHODS: We performed a descriptive audit of data prospectively reported to the Australasian Diabetes Data Network (ADDN) registry. Data were collected from six tertiary pediatric diabetes centers across Australia (New South Wales, Queensland, South Australia, Western Australia, and Victoria) and NZ (Auckland). Children and adolescents diagnosed with type 2 diabetes aged ≤ 18 years with data reported to ADDN between 2012 and 2017 were included. Age, sex, ethnicity, HbA1c, blood pressure, BMI, waist circumference and lipid profile at first visit were assessed. RESULTS: There were 269 cases of type 2 diabetes in youth reported to ADDN between 2012 and 2017. The most common ethnicities were Indigenous Australian in 56/243 (23%) and NZ Maori or Pacifica in 47 (19%). Median age at diagnosis was 13.7 years and 94% of participants were overweight or obese. Indigenous Australian and Maori/Pacifica children were younger at diagnosis compared with nonindigenous children: median 13.3 years (indigenous Australian); 13.1 years (Maori/Pacifica); 14.1 years (nonindigenous), p = 0.005. HbA1c was higher in indigenous Australian (9.4%) and Maori/Pacifica youth (7.8%) compared with nonindigenous (6.7%) p < 0.001. BMI-SDS was higher in Maori/Pacifica youth (2.3) compared with indigenous Australian (2.1) and nonindigenous (2.2) p = 0.011. CONCLUSIONS: Indigenous Australian and Maori/Pacifica youth in ADDN were younger and had worse glycaemic control at diagnosis of type 2 diabetes. Our findings underscore the need to consider targeted and earlier screening in these "high-risk" populations.

The Adolescent Cardio-Renal Intervention Trial (AdDIT): retinal vascular geometry and renal function in adolescents with type 1 diabetes.

AIMS/HYPOTHESIS: We examined the hypothesis that elevation in urinary albumin creatinine ratio (ACR) in adolescents with type 1 diabetes is associated with abnormal retinal vascular geometry (RVG) phenotypes. METHODS: A cross-sectional study at baseline of the relationship between ACR within the normoalbuminuric range and RVG in 963 adolescents aged 14.4 ± 1.6 years with type 1 diabetes (median duration 6.5 years) screened for participation in AdDIT. A validated algorithm was used to categorise log10 ACR into tertiles: upper tertile ACR was defined as 'high-risk' for future albuminuria and the lower two tertiles were deemed 'low-risk'. RVG analysis, using a semi-automated computer program, determined retinal vascular calibres (standard and extended zones) and tortuosity. RVG measures were analysed continuously and categorically (in quintiles: Q1-Q5) for associations with log10 ACR and ACR risk groups. RESULTS: Greater log10 ACR was associated with narrower vessel calibres and greater tortuosity. The high-risk group was more likely to have extended zone vessel calibres in the lowest quintile (arteriolar Q1 vs Q2-Q5: OR 1.67 [95% CI 1.17, 2.38] and venular OR 1.39 [0.98, 1.99]) and tortuosity in the highest quintile (Q5 vs Q1-Q4: arteriolar OR 2.05 [1.44, 2.92] and venular OR 2.38 [1.67, 3.40]). The effects of retinal vascular calibres and tortuosity were additive such that the participants with the narrowest and most tortuous vessels were more likely to be in the high-risk group (OR 3.32 [1.84, 5.96]). These effects were independent of duration, blood pressure, BMI and blood glucose control. CONCLUSIONS/INTERPRETATION: Higher ACR in adolescents is associated with narrower and more tortuous retinal vessels. Therefore, RVG phenotypes may serve to identify populations at high risk of diabetes complications during adolescence and well before onset of clinical diabetes complications.

Innovative technology shows impact of glycaemic control on peripheral retinal vessels in adolescents with type 1 diabetes.

AIMS/HYPOTHESIS: Retinal imaging enables non-invasive microvasculature assessment; however, only central retinal vessels have been studied in type 1 diabetes. Peripheral smaller vessels have a major haemodynamic role and may differ from central vessels in their response to the diabetic milieu. We hypothesise that diabetes has a greater impact on peripheral retinal vessels vs central vessels. METHODS: Retinal photographs from adolescents (n = 736; age 12-20 years) with type 1 diabetes were graded (Singapore I Vessel Assessment) with vessel calibres measured in the 'central zone' as central retinal arteriolar and venular equivalents (CRAE and CRVE, respectively) and the 'extended zone' as mean width of arterioles and venules (MWa and MWv, respectively). Multivariable linear regression was used to explore associations between vessel calibres and HbA1c, diabetes duration, sex and BP. RESULTS: Mean ± SD age was 14.1 ± 1.5 years, HbA1c was 8.5 ± 1.3% (69.4 ± 14.1 mmol/mol) and median diabetes duration was 4.9 years (interquartile range 3.1-7.6 years). Wider MWa was associated with HbA1c (ß 0.01 [95% CI 0.004, 0.03]), longer diabetes duration (0.07 [0.02, 0.13]) and higher systolic BP (0.04 [0.02, 0.05]). MWv was associated with HbA1c (0.02 [0.009, 0.03]) and higher systolic BP (0.04 [0.03, 0.06]). CRAE was associated with longer diabetes duration (0.93 [0.58, 1.28]) and higher systolic BP (-0.28 [-0.37, -0.19]). CRVE was associated with longer diabetes duration (0.91 [0.42, 1.41]) and higher systolic BP (-0.20 [-0.33, -0.07]). Girls had wider vessels (for all four calibre measurements). CONCLUSIONS/INTERPRETATION: In adolescents with type 1 diabetes, higher HbA1c is associated with adverse changes to peripheral smaller retinal vessels but not central vessels. The predictive value of retinal vascular imaging should be evaluated using longitudinal data.

Optimal Frequency of Retinopathy Screening in Adolescents With Type 1 Diabetes: Markov Modeling Approach Based on 30 Years of Data.

OBJECTIVE: Current guidelines recommend biennial diabetic retinopathy (DR) screening commencing at the age of 11 years and after 2-5 years' duration of type 1 diabetes. Growing evidence suggests less frequent screening may be feasible. RESEARCH DESIGN AND METHODS: Prospective data were collected from 2,063 youth with type 1 diabetes who were screened two or more times between 1990 and 2019. Baseline (mean ± SD) age was 13.3 ± 1.8 years, HbA1c was 8.6 ± 1.3% (70.1 ± 14.7 mmol/mol), diabetes duration was 5.6 ± 2.8 years, and follow-up time was 4.8 ± 2.8 years. DR was manually graded from 7-field retinal photographs using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Markov chain was used to calculate probabilities of DR change over time and hazard ratio (HR) of DR stage transition. RESULTS: The incidence of moderate nonproliferative DR (MNPDR) or worse was 8.6 per 1,000 patient-years. Probabilities of transition to this state after a 3-year interval were from no DR, 1.3%; from minimal DR, 5.1%; and from mild DR, 22.2%, respectively. HRs (95% CIs) for transition per 1% current HbA1c increase were 1.23 (1.16-1.31) from no DR to minimal NPDR, 1.12 (1.03-1.23) from minimal to mild NPDR, and 1.28 (1.13-1.46) from mild to MNPDR or worse. HbA1c alone explained 27% of the transitions between no retinopathy and MNPDR or worse. The addition of diabetes duration into the model increased this value to 31% (P = 0.03). Risk was also increased by female sex and higher attained age. CONCLUSIONS: These results support less frequent DR screening in youth with type 1 diabetes without DR and short duration. Although DR progression to advanced stages is generally slow, higher HbA1c greatly accelerates it.

Barth syndrome with severe dilated cardiomyopathy and growth hormone resistance: a case report.

OBJECTIVES: To describe the metabolic and endocrine features of a patient with Barth syndrome who showed evidence of growth hormone resistance. CASE PRESENTATION: A male proband deteriorated rapidly with lactic acidosis after a circumcision at age three weeks and was found to have severe dilated cardiomyopathy. A cardiomyopathy gene panel led to the diagnosis of TAZ-deficiency Barth syndrome. He subsequently experienced hypotonia and gross motor delay, feeding difficulties for the first four years, constitutional growth delay and one episode of ketotic hypoglycaemia. Cardiomyopathy resolved on oral anti-failure therapy by age three years. He had a hormonal pattern of growth hormone resistance, and growth hormone treatment was considered, however height velocity improved spontaneously after age 3½ years. He also had biochemical primary hypothyroidism. CONCLUSIONS: With careful metabolic management with l-arginine supplementation, overnight corn starch, and a prescribed exercise program, our patient's strength, endurance, level of physical activity and body composition improved significantly by age six years.

Hemoglobin A1c Patterns of Youth With Type 1 Diabetes 10 Years Post Diagnosis From 3 Continents.

OBJECTIVES: Distinct hemoglobin A1c (HbA1c) trajectories during puberty are identified in youth with established type 1 diabetes (T1D). We used data from 3 international registries to evaluate whether distinct HbA1c trajectories occur from T1D onset. METHODS: Participants were <18 years old at diagnosis with at least 1 HbA1c measured within 12 months post diagnosis, along with ≥3 duration-year-aggregated HbA1c values over 10 years of follow-up. Participants from the Australasian Diabetes Data Network (n = 7292), the German-Austrian-Luxembourgian-Swiss diabetes prospective follow-up initiative (Diabetes Patienten Verlaufsdokumentation) (n = 39 226) and the US-based Type 1 Diabetes Exchange Clinic Registry (n = 3704) were included. With group-based trajectory modeling, we identified unique HbA1c patterns from the onset of T1D. RESULTS: Five distinct trajectories occurred in all 3 registries, with similar patterns of proportions by group. More than 50% had stable HbA1c categorized as being either low stable or intermediate stable. Conversely, ∼15% in each registry were characterized by stable HbA1c >8.0% (high stable), and ∼11% had values that began at or near the target but then increased (target increase). Only ∼5% of youth were above the target from diagnosis, with an increasing HbA1c trajectory over time (high increase). This group differed from others, with higher rates of minority status and an older age at diagnosis across all 3 registries (P ≤ .001). CONCLUSIONS: Similar postdiagnostic HbA1c patterns were observed across 3 international registries. Identifying the youth at the greatest risk for deterioration in HbA1c over time may allow clinicians to intervene early, and more aggressively, to avert increasing HbA1c.

Insulin micro-secretion in Type 1 diabetes and related microRNA profiles.

The aim of this cross-sectional study was to compare plasma C-peptide presence and levels in people without diabetes (CON) and with Type 1 diabetes and relate C-peptide status to clinical factors. In a subset we evaluated 50 microRNAs (miRs) previously implicated in beta-cell death and associations with clinical status and C-peptide levels. Diabetes age of onset was stratified as adult (≥ 18 y.o) or childhood (< 18 y.o.), and diabetes duration was stratified as ≤ 10 years, 10-20 years and > 20 years. Plasma C-peptide was measured by ultrasensitive ELISA. Plasma miRs were quantified using TaqMan probe-primer mix on an OpenArray platform. C-peptide was detectable in 55.3% of (n = 349) people with diabetes, including 64.1% of adults and 34.0% of youth with diabetes, p < 0.0001 and in all (n = 253) participants without diabetes (CON). C-peptide levels, when detectable, were lower in the individuals with diabetes than in the CON group [median lower quartile (LQ)-upper quartile (UQ)] 5.0 (2.6-28.7) versus 650.9 (401.2-732.4) pmol/L respectively, p < 0.0001 and lower in childhood versus adult-onset diabetes [median (LQ-UQ) 4.2 (2.6-12.2) pmol/L vs. 8.0 (2.3-80.5) pmol/L, p = 0.02, respectively]. In the childhood-onset group more people with longer diabetes duration (> 20 years) had detectable C-peptide (60%) than in those with shorter diabetes duration (39%, p for trend < 0.05). Nine miRs significantly correlated with detectable C-peptide levels in people with diabetes and 16 miRs correlated with C-peptide levels in CON. Our cross-sectional study results are supportive of (a) greater beta-cell function loss in younger onset Type 1 diabetes; (b) persistent insulin secretion in adult-onset diabetes and possibly regenerative secretion in childhood-onset long diabetes duration; and (c) relationships of C-peptide levels with circulating miRs. Confirmatory clinical studies and related basic science studies are merited.

Extended-Zone Retinal Vascular Caliber and Risk of Diabetic Retinopathy in Adolescents with Type 1 Diabetes.

PURPOSE: Retinal vascular caliber has been linked to diabetic retinopathy (DR). Newer imaging technologies allow analysis of retinal vascular caliber beyond the standard areas surrounding the optic disc. We investigated the vascular caliber in extended zones in prediction of DR in adolescents with type 1 diabetes. DESIGN: Prospective, longitudinal study. PARTICIPANTS: Adolescents (n = 904) who attended the diabetes complications assessment service at the Children's Hospital at Westmead. METHODS: Retinal caliber was assessed from baseline retinal photographs with a semiautomated computer software Singapore I Vessel Assessment: standard zone retinal vessel calibers were summarized as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE), and extended-zone vessels (>2 disc diameters from the optic disc margin) were summarized as mean width of arterioles (MWa) and mean width of venules (MWv). MAIN OUTCOME MEASURES: Retinal vessel calibers at baseline (upper 3 quartiles vs. lowest quartiles [Q2-4 vs. Q1]) and moderate DR (stage 3 or more) were analyzed using multivariate generalized estimating equations, with results expressed as odds ratios (OR) and 95% confidence intervals (CIs). RESULTS: Among the 904 participants, baseline mean age ± standard deviation was 14.0 ± 1.5 years, hemoglobin A1C (HbA1C) level was 8.5 ± 1.3%, and median diabetes duration 4.6 years. After a median 3-year follow-up, 15% of adolescents demonstrated moderate DR. Wider extended-zone retinal arteriolar caliber (MWa; OR, 3.6 [95% CI, 2.06-6.1], comparing Q2-4 vs. Q1) and venular caliber (MWv; OR, 4.2 [95% CI, 2.2-7.5]) predicted moderate DR after adjusting for HbA1C and blood pressure. Standard zone CRAE and CRVE were not associated with moderate DR. CONCLUSIONS: Extended-zone retinal vessel caliber predicts moderate DR in adolescents with type 1 diabetes.

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.

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.

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 (ß = 2.5, 95% CI 0.2-4.8, P = 0.03) and lower RMSSD (ß = -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.

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.

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.

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.

The natural history of vitamin D deficiency in African refugees living in Sydney.

OBJECTIVE: To describe the natural history of vitamin D deficiency in an at-risk population of African migrants living in Sydney. DESIGN, SETTING AND PARTICIPANTS: Opportunistic study of 25-hydroxyvitamin D [25(OH)D] concentrations over time in a community-based cohort of North African refugee families living in south-western Sydney. As part of a health-screening program, serum concentrations of 25(OH)D, parathyroid hormone (PTH), calcium, phosphate (PO(4)) and alkaline phosphatase (ALP) were measured in September 2006 (end of winter, T1). Results for 25(OH)D were made available, and treatment was recommended as appropriate. In February-March 2007 (end of summer, T2), in the setting of a separate study of high-dose vitamin D (stoss) therapy, the same cohort was contacted, and measurements were repeated. MAIN OUTCOME MEASURES: Changes in 25(OH)D, PTH, ALP and PO(4) concentrations between T1 and T2 in those who had not received vitamin D supplementation in the intervening period. RESULTS: We collected data from 149 participants at T1; by T2, 58 participants (39%) had been excluded or lost to follow-up. Data from 91 participants (46% female), all of whom had Type VI (very dark) skin pigmentation, were included in the analysis. All 91 were 25(OH)D deficient at T1. Between T1 and T2, mean 25(OH)D serum concentration increased from 19 nmol/L (SD, 5.6 nmol/L) to 36 nmol/L (SD, 12.4 nmol/L) (P < 0.001). Of the 91 participants, 79 (87%) remained vitamin D deficient at T2. Serum PTH and ALP activity decreased between T1 and T2 (P < 0.05). CONCLUSION: Despite a significant increase in 25(OH)D serum concentration over the study period, most participants (87%) remained 25(OH)D deficient at the end of summer. Our results support the current consensus that recommends annual screening for vitamin D deficiency and routine vitamin D supplementation in at-risk populations, such as dark-skinned or veiled groups.