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

Prevalence of polycystic ovary syndrome and its clinical and hormonal profile in young females with type 1 diabetes mellitus: experience from a teaching institution of India

OBJECTIVE

To investigate the prevalence of polycystic ovary syndrome and its clinical and hormonal profile in females with type 1 diabetes.

MATERIALS AND METHODS

65 T1DM females were evaluated for presence of PCOS by Rotterdam ESHRE/ASRM consensus criteria and compared with age and BMI matched females with PCOS without diabetes and females with T1DM without PCOS.

RESULTS

According to Rotterdam criteria 18/65 (27%) had PCOS. Prevalence of androgen excess, hirsutism, menstrual dysfunction and PCOM was 26%, 3%, 21% and 52%, respectively. Females with T1DM who had PCOS did not differ from females with T1DM without PCOS. When the group of T1DM with PCOS was compared with PCOS females without diabetes, they had significantly lower hirsutism score (median, IQR; 1.5, 0-3 vs. 11.5, 0-16.5, p = 0.04), significantly higher waist hip ratio (0.91, 0.89-0.99 vs. 0.86, 0.80-0.89, p = 0.004) and SHBG (in nmol, 54.4, 38-86.2 vs. 28.3, 20.4-37.4, p = 0.004).

CONCLUSION

Females with T1DM have a high prevalence of menstrual abnormalities, hyperandrogenism and PCOS which is not related to metabolic control, age of onset of diabetes or insulin dose. Polycystic ovary syndrome, hyperandrogenism, type 1 diabetes, menstrual irregularity, hirsutism.

Heart Rate Variability for the Early Detection of Cardiac Autonomic Dysfunction in Type 1 Diabetes

Type 1 diabetes mellitus (T1DM) has an important impact on morbidity and mortality because it may start early in life. Therefore, the early detection of cardiovascular autonomic neuropathy (DCAN) in T1DM patients is important to intervene quickly and prevent further deterioration. Traditional autonomic function tests detect abnormalities in severely symptomatic patients but they are difficult to be standardized, require the patient’s active participation and their sensitivity to the early disease is limited. In comparison, heart rate variability (HRV) is easier to be measured and standardized. Therefore, we aim to find the HRV indexes that better identify DCAN at an early stage in T1DM patients, and evaluate if HRV is a valid alternative to traditional tests. For this aim, we administered the SCOPA-AUT questionnaire on symptoms of autonomic dysfunction as well as deep breathing, Valsalva, handgrip, head-up tilt (HUT), and cold-pressor tests, to 52 T1DM patients and 27 controls. We calculated HRV indexes during supine rest (SUP) and HUT, assessing differences between groups and postures by a linear mixed-effect model for repeated measures. Receiver Operating Characteristic (ROC) analysis quantified how each HRV index and autonomic test distinguishes between patients and controls. We found that the SCOPA-AUT score was slightly but significantly (p < 0.05) greater in patients, indicating an early DCAN. T1DM patients preserved the HRV response to changing posture but in SUP they showed significantly lower standard deviation and vagal indexes of HRV than controls. The area under the ROC curve of these HRV indexes was not lower than 0.68. By contrast, traditional autonomic tests did not differ between groups. Therefore, early DCAN initially causes an impairment of the cardiac vagal control manifest in conditions of elevated vagal tone, as in SUP. Compensatory adjustments of the sympathetic control might explain the unaltered response to traditional autonomic tests. In conclusion, vagal HRV indexes in SUP help to identify early DCAN better than traditional tests, potentially allowing rapid interventions.

A systematic review of the prevalence, risk factors and screening tools for autonomic and diabetic peripheral neuropathy in children, adolescents and young adults with type 1 diabetes

AIMS

We aimed to estimate the prevalence of Diabetic peripheral neuropathy (DPN) and Cardiac autonomic neuropathy (CAN) in youth with type 1 diabetes; identify key risk factors; identify the most useful tests for the diagnostic evaluation of DPN and CAN; identify key treatment options for DPN and CAN.

METHODS

A systematic search was performed including studies published in the last 15 years. PICO framework was used in the selection process and evidence was assessed using the GRADE system.

RESULTS

A total of 758 studies were identified and a final number of 49 studies were included in this systematic review. According to moderate-high level quality studies, the prevalence of probable DPN, ranged between 13.5 and 62%; subclinical DPN between 22 and 88%; confirmed DPN between 2.6 and 11%. The Michigan Neuropathy Screening Instrument was the tool with higher sensitivity and specificity for detecting DPN, which needs to be confirmed by nerve conduction velocity. The prevalence of CAN was 4-39%. Specific treatment options for DPN or CAN in patients younger than 25 years are not available. Key risk factors for DPN and CAN are hyperglycemia/HbA1c, age, diabetes duration, the presence of other microvascular complications, waist/height ratio, lipid profile and blood pressure. For CAN, additional risk factors were cigarette smoking, BMI and total daily insulin.

CONCLUSIONS

Prevalence of neuropathy in youth with type 1 diabetes varies depending on different screening methods and characteristics of the study populations. However, the assessed studies confirmed a relatively high prevalence of subclinical neuropathy, reiterating the importance of early identification of risk factors to prevent this complication.

Large fibre, small fibre and autonomic neuropathy in adolescents with type 1 diabetes: A systematic review

AIMS

To estimate the prevalence of neuropathy in adolescents with type 1 diabetes.

METHODS

Systematic collection of published studies exploring the prevalence of large fibre neuropathy (LFN), small fibre neuropathy (SFN), and autonomic neuropathy in adolescents with type 1 diabetes. Following prospective registration (Prospero CRD42020206093), PubMed, EMBASE, and Cochrane Library were searched for studies from 2000 to 2020. PICO framework was used in the selection process (Population: adolescents aged 10-19 years with type 1 diabetes; Intervention: diagnostic methods for neuropathy; Comparison: reference data; Outcome: data on prevalence or comparison). Data were extracted concerning study quality based on available data and established methods for determining and diagnosing various neuropathy types.

RESULTS

From 2,017 initial citations, 27 studies (7589 participants) fulfilled eligibility criteria. The study population (47% males) had a diabetes duration between 4.0 and 10.6 years, and HbA1c level between 7.3 and 10.8%, 56-95 mmol/mol. The prevalence of LFN, based on nerve conduction studies, was 10-57%. Based on other tests for neuropathy, the prevalence of LFN and SFN was 12-62%, and that of cardiac autonomic neuropathy was 12-75%.

CONCLUSION

The described prevalence of neuropathy in adolescents with type 1 diabetes varied, which can be methodological due to different screening methods and classifications of neuropathy.

Diabetic neuropathy in children and youth: New and emerging risk factors

Pediatric neuropathy attributed to metabolic dysfunction is a well-known complication in children and youth with type 1 diabetes. Moreover, the rise of obesity and in particular of type 2 diabetes may cause an uptick in pediatric neuropathy incidence. However, despite the anticipated increase in neuropathy incidence, pathogenic insights and strategies to prevent or manage neuropathy in the setting of diabetes and obesity in children and youth remain unknown. Data from adult studies and available youth cohort studies are providing an initial understanding of potential diagnostic, management, and preventative measures in early life. This review discusses the current state of knowledge emanating from these efforts, with particular emphasis on the prevalence, clinical presentation, diagnostic approaches and considerations, and risk factors of neuropathy in type 1 and type 2 diabetes in children and youth. Also highlighted are current management strategies and recommendations for neuropathy in children and youth with diabetes. This knowledge, along with continued and sustained emphasis on identifying and eliminating modifiable risk factors, completing randomized controlled trials to assess effectiveness of strategies like weight loss and exercise, and enhancing awareness to support early detection and prevention, are pertinent to addressing the rising incidence of neuropathy associated with diabetes and obesity in children and youth.

Heart Rate Variability and Cardiorespiratory Fitness in Non-Hispanic Black Versus Non-Hispanic White Adolescents With Type 1 Diabetes

BACKGROUND

Evidence indicates that fewer non-Hispanic black versus non-Hispanic white youths with type 1 diabetes are meeting treatment goals for optimal glycemic outcomes, predisposing them to risks for cardiovascular (CV) morbidity and mortality in adulthood.

PURPOSE

We sought to assess the association of sex and race with heart rate variability (HRV) and cardiorespiratory fitness in adolescents with type 1 diabetes. The association between the HRV and cardiorespiratory outcomes with glucose control was also examined.

METHODS

A secondary data analysis of 95 adolescents with type 1 diabetes (n = 66 non-Hispanic white n = 29 non-Hispanic black) was used. Using 24-hour Holter recordings, spectral and time domain measures of HRV were obtained. Cardiorespiratory fitness using a graded exercise test was completed. Descriptive statistics and Pearson correlation coefficients were used to assess associations between glucose control and study outcomes, and general linear models were applied to explore and quantify associations of sex and race with HRV and cardiorespiratory fitness.

RESULTS

Body mass index (mean [standard deviation]) was similar between non-Hispanic black (23.5 [3.9]) and non-Hispanic white (22.7 [3.8]) adolescents. Females and non-Hispanic black adolescents had significantly lower HRV and cardiorespiratory fitness levels. Moderate associations were found between lower HRV and poorer glycemic control (HbA1c). Recent HbA1c was significantly higher in non-Hispanic black (9.7 [1.8]) than non-Hispanic white (8.2 [1.2]).

CONCLUSION

Findings support the importance of early identification of CV health risks in adolescents with type 1 diabetes, particularly for non-Hispanic black adolescents. Interventions focused on overall improvement in glycemic control for adolescents with type 1 diabetes are a priority for minimizing future CV complications.

Effects of Metformin Added to Insulin in Adolescents with Type 1 Diabetes: An Exploratory Crossover Randomized Trial

BACKGROUND

To comprehensively assess the effects of metformin added to insulin on metabolic control, insulin sensitivity, and cardiovascular autonomic function in adolescents with type 1 diabetes.

MATERIALS AND METHODS

This was an exploratory, crossover, randomized trial conducted in adolescents with type 1 diabetes aged 12-18 years old. Participants were randomly received metformin (≤1000 mg/d) added to insulin for 24 weeks followed by insulin monotherapy for a subsequent 24 weeks or vice versa. Blood pressure, body mass index, insulin dose, estimated insulin sensitivity, glycated hemoglobin A1c (HbA1c), and lipid profiles were measured, with a 72-hour continuous glucose monitoring and 24-hour Holter monitoring performed at baseline, 24, and 50 weeks for the assessments of glucose variability and heart rate variability.

RESULTS

Seventeen patients with mean ± SD age 14.4 ± 2.3 years, body mass index 18.17 ± 1.81 kg/m², median (IQR) diabetes duration 4.50 (3.58, 6.92) years, and HbA1c 9.0% (8.5%, 9.4%) were enrolled. The between-group difference in HbA1c of 0.28% (95% CI -0.39 to 0.95%) was not significant (P = 0.40). Changes in body mass index, insulin dose, blood pressure, lipid profiles, and estimated insulin sensitivity were similar for metformin add-on vs. insulin monotherapy. Glucose variability also did not differ. Compared with insulin monotherapy, metformin add-on significantly increased multiple heart rate variability parameters.

CONCLUSIONS

Metformin added to insulin did not improve metabolic control or glucose variability in lean/normal-weight adolescents with type 1 diabetes. However, metformin added to insulin significantly increased heart rate variability, suggesting that metformin might improve cardiovascular autonomic function in this population.

Effect of metformin on clinical and biochemical hyperandrogenism in adolescent girls with type 1 diabetes

Background Hyperandrogenism with or without polycystic ovarian syndrome is seen in adolescents with type 1 diabetes (T1D), especially those with suboptimal control. Objective To assess the effect of metformin on hyperandrogenism and ovarian function in adolescents with T1D. Methods This prospective study included 28 T1D females showing signs of hyperandrogenism. History taking (detailed diabetes history and menstrual history) and anthropometric measurements (weight, height, body mass index [BMI], waist and hip circumference) were initially performed, and then the patients were assessed for the manifestations of hyperandrogenism (acne, hirsutism as well as pelvic ultrasound [U/S] for ovarian morphology). Biochemical evaluation for ovulation (progesterone assessment during the luteal phase), sex steroids (estradiol, testosterone, dehydroepiandrosterone sulfate [DHEAS] and androstenedione), prolactin, glycemic control (hemoglobin A1c [HbA1c]) and gonadotropin levels (follicle stimulating hormone [FSH] and luteinizing hormone [LH]) was done. Patients were subjected to 500 mg metformin twice daily orally for 1 year, and then the patients were re-evaluated for clinical and biochemical parameters. Results Metformin therapy resulted in a significant reduction in weight (p = 0.001), BMI (p = 0.002), acne (p = 0.008), hirsutism score (0.007), LH (p = 0.008), testosterone (p < 0.001) and androstenedione levels (p = 0.028) in adolescent girls with T1D. Regarding menstrual irregularities, there was a significant reduction in the number of patients with oligomenorrhea (68%) with a p value of <0.001. However, there were no significant reduction in the daily insulin requirements (p = 0.782) or HbA1c (p = 0.068). Nausea and/or abdominal pain were the commonly reported side effects of metformin (64%). Conclusions Metformin as an insulin sensitizing agent improved the BMI and cycle regularity together with clinical and biochemical hyperandrogenism in T1D adolescent girls. However, it did not improve their glycemic control.

Autoimmune Disease in Women: Endocrine Transition and Risk Across the Lifespan

Women have a higher incidence and prevalence of autoimmune diseases than men, and 85% or more patients of multiple autoimmune diseases are female. Women undergo sweeping endocrinological changes at least twice during their lifetime, puberty and menopause, with many women undergoing an additional transition: pregnancy, which may or may not be accompanied by breastfeeding. These endocrinological transitions exert significant effects on the immune system due to interactions between the hormonal milieu, innate, and adaptive immune systems as well as pro- and anti-inflammatory cytokines, and thereby modulate the susceptibility of women to autoimmune diseases. Conversely, pre-existing autoimmune diseases themselves impact endocrine transitions. Concentration-dependent effects of estrogen on the immune system; the role of progesterone, androgens, leptin, oxytocin, and prolactin; and the interplay between Th1 and Th2 immune responses together maintain a delicate balance between host defense, immunological tolerance and autoimmunity. In this review, multiple autoimmune diseases have been analyzed in the context of each of the three endocrinological transitions in women. We provide evidence from human epidemiological data and animal studies that endocrine transitions exert profound impact on the development of autoimmune diseases in women through complex mechanisms. Greater understanding of endocrine transitions and their role in autoimmune diseases could aid in prediction, prevention, and cures of these debilitating diseases in women.

Higher body mass index predicts cardiac autonomic dysfunction: A longitudinal study in adolescent type 1 diabetes

BACKGROUND

Obesity is associated with an increased risk of cardiovascular morbidity in adults with diabetes.

OBJECTIVE

To examine the predictive role of body mass index (BMI) and adiposity on cardiac autonomic function in childhood onset type 1 diabetes.

SUBJECTS

Two hundred and fifty-three participants with type 1 diabetes (aged 8-30 years) were assessed for diabetes complications at a tertiary hospital, and followed over 7 years (total 922 visits).

METHODS

Heart rate variability (HRV) measures assessed by 10-minute electrocardiography recording using LabChart Pro were standard deviation of RR intervals, time between consecutive QRS complexes, [SDNN], root mean squared difference of successive RR intervals (RMSSD), triangular index (TI), and low to high frequency ratio [LF:HF]. Multivariable generalized estimating equations were used to model the longitudinal associations between HRV measures and clinical variables (BMI standard deviation scores [SDS], waist:height ratio, total daily insulin dose/kg (TDD) and hemoglobin A1c [HbA1c]).

RESULTS

At baseline, mean age was 14.4 ± 2.7 years, diabetes duration 7.1 ± 3.7 years, HbA1c 8.3% ± 1.5% (67 ± 16 mmol/mol), and 33% were overweight/obese (BMI ≥85th percentile). At final visit, mean age was 18.5 ± 2.7 years, duration 11.3 ± 3.9 years, HbA1c 9.0% ± 1.8% (75 ± 20 mmol/mol), and 40% were overweight/obese. Adiposity (higher BMI SDS or waist: height ratio) was a significant predictor of worse HRV (lower SDNN, RMSSD; P < .05), while higher HbA1c and TDD predicted all adverse HRV measures (lower SDNN, RMSSD, TI; P < .05) and abnormal sympathovagal balance (higher LF:HF ratio; P < .05).

CONCLUSIONS

Higher BMI and central adiposity are associated with cardiac autonomic dysfunction in childhood onset type 1 diabetes, after adjusting for HbA1c. Interventions targeting overweight/obesity during adolescence may optimize long-term vascular health in type 1 diabetes.

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

AIMS

To examine QT intervals corrected for heart rate (QTc) in adolescents with Type 1 diabetes compared with control subjects, and to determine associations with metabolic control and autonomic function.

METHODS

Resting electrocardiogram recordings of 142 adolescents with Type 1 diabetes [mean (sd) age 15.3 (2.0) years, diabetes duration 9.0 (3.5) years, HbA1c 71 (17) mmol/mol or 8.7 (1.6)%] and 125 control subjects [mean (sd) age 15.7 (2.5) years] were used to calculate QTc duration and derive mean heart rate and heart rate variability (HRV) values. Linear and logistic regression models were used to examine the associations between QTc, metabolic control and autonomic function (HRV and pupillary function).

RESULTS

QTc duration was not significantly different between subjects with Type 1 diabetes and control subjects (mean duration 392 vs 391 ms; P = 0.65). In the Type 1 diabetes group, QTc was positively associated with HbA1c [β = 4 (95% CI 2, 6); P < 0.001] and inversely associated with severe hypoglycaemic events [β = -10 (95% CI -20,-2); P = 0.01], less insulin/kg [β = -12 (95% CI -22, -2); P = 0.024] and less HRV. In the Type 1 diabetes group, QTc in the highest quintile (≥409 ms) vs quintiles 1-4 had more pupillary abnormalities (83 vs 56%; P = 0.03), lower pupillary maximum constriction velocity (4.8 vs 5.3 mm/s; P = 0.04), higher heart rate (78 vs 72 beats per min; P = 0.02) and lower HRV (standard deviation of mean NN intervals 4.0 vs 4.3 ms, P = 0.004 and root-mean-square difference of successive NN intervals 3.7 vs 4.1 ms; P = 0.004).

CONCLUSIONS

Although there are concerns about hypoglycaemia in general in people with Type 1 diabetes, chronic hyperglycaemia, rather than intermittent hypoglycaemia, appears to be more deleterious to autonomic cardiac function, even in adolescence. Longer QTc was associated with higher HbA1c concentration, lower risk of hypoglycaemia and autonomic dysfunction. Longitudinal studies are warranted.

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.

Type 1 Diabetes and Polycystic Ovary Syndrome: Systematic Review and Meta-analysis

BACKGROUND

A few small studies have reported increased prevalences of polycystic ovary syndrome (PCOS) and symptoms of androgen excess in women with type 1 diabetes.

PURPOSE

We performed a systematic review and meta-analysis of studies evaluating androgen excess symptoms and PCOS in women with type 1 diabetes.

DATA SOURCES

The Entrez-PubMed and Scopus electronic databases were used.

STUDY SELECTION

We selected studies addressing androgen excess signs, symptoms, and disorders in girls, adolescents, and adult women with type 1 diabetes.

DATA EXTRACTION

The main outcome measures were prevalences of PCOS, hyperandrogenemia, hirsutism, menstrual dysfunction, and polycystic ovarian morphology (PCOM).

DATA SYNTHESIS

Nine primary studies involving 475 adolescent or adult women with type 1 diabetes were included. The prevalences of PCOS and associated traits in women with type 1 diabetes were 24% (95% CI 15-34) for PCOS, 25% (95% CI 17-33) for hyperandrogenemia, 25% (95% CI 16-36) for hirsutism, 24% (95% CI 17-32) for menstrual dysfunction, and 33% (95% CI 24-44) for PCOM. These figures are considerably higher than those reported earlier in the general population without diabetes.

LIMITATIONS

The data collected in the original studies were heterogeneous in age, race, ethnicity, and criteria used for the diagnosis of PCOS; yet, we used a quality-effects model in the meta-analyses to overcome this limitation.

CONCLUSIONS

PCOS and its related traits are frequent findings in women with type 1 diabetes. PCOS may contribute to the subfertility of these women by a mechanism that does not directly depend on glycemic/metabolic control among other negative consequences for their health. Hence, screening for PCOS and androgen excess should be included in current guidelines for the management of type 1 diabetes in women.

Gastric Emptying Is More Rapid in Adolescents With Type 1 Diabetes and Impacts on Postprandial Glycemia

CONTEXT

Gastric emptying is a critical determinant of postprandial glycemic control in health and type 1 diabetes. There are few studies that assess the relationship between gastric emptying and postprandial glycaemia in adolescents with type 1 diabetes.

OBJECTIVE

The objectives of the study were to quantify gastric emptying in adolescents with type 1 diabetes and examine its relationship to postprandial glycaemia and autonomic function.

DESIGN

This was a case-control study. Gastric half-emptying time of a solid meal was measured by a (13)C-octanoate breath test. Cardio-autonomic function was measured by heart rate variability. Chronic and postprandial gastrointestinal symptoms were evaluated by questionnaire and visual analog scales. Blood glucose concentrations were monitored frequently during the study.

SETTING

The study was conducted at a tertiary pediatric hospital in South Australia.

PARTICIPANTS

Thirty adolescents (aged 15 ± 2.5 y) with type 1 diabetes and age- and sex-matched controls (gastric emptying, n = 20; heart rate variability, n = 135) participated in the study.

MAIN OUTCOME

Gastric half-emptying time was the main outcome in the study.

RESULTS

Gastric emptying was more rapid in subjects with type 1 diabetes than controls [median half emptying time 78 (interquartile range 61-99) vs 109 (interquartile range 71-124) min, P = .02]. The postprandial rise in blood glucose at 60 minutes was strongly related to gastric half-emptying time (R = -0.65, P = .0001). Gastric emptying was slower in subjects with fasting hyperglycemia but was not related to heart rate variability. Nausea, bloating, and anxiety were related to fasting glycemia (P = .03).

CONCLUSION

Rapid gastric emptying is a major determinant of postprandial glycemia in adolescents with type 1 diabetes. This observation has significant implications for therapy.

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

OBJECTIVE

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

RESEARCH DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Puberty as an accelerator for diabetes complications

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

Positive psychological characteristics in diabetes: a review

Positive psychological characteristics, such as optimism, self-efficacy, and resilience, have been increasingly associated with improved outcomes in medically ill individuals. However, there has been minimal systematic review of these characteristics and their associations with outcomes in people with diabetes. We aim to review these associations, their potential mediating mechanisms, and the evidence supporting interventions targeting these qualities. In people with diabetes, positive psychological characteristics are significantly associated with improved glycemic control, fewer complications, and reduced rates of mortality. Potential mechanisms mediating these associations include behavioral factors (e.g., improved treatment adherence), reduced inflammation, and improved neuroendocrine and autonomic functioning. Most psychosocial treatments in this population have focused on improving self-efficacy and resilience; such interventions may improve quality of life, well-being, and diabetes self-care. While untested in diabetes, interventions to boost other positive characteristics have been effective in other medically ill patients and may warrant further study in this cohort.