Older age of childhood type 1 diabetes onset is associated with islet autoantibody positivity >30 years later: the Pittsburgh Epidemiology of Diabetes Complications Study

AIMS

To examine the association between islet autoantibody positivity and clinical characteristics, residual β-cell function (C-peptide) and prevalence of complications in a childhood-onset (age <17 years), long-duration (≥32 years) type 1 diabetes cohort.

METHODS

Islet autoantibodies (glutamic acid decarboxylase, insulinoma-associated protein 2 and zinc transporter-8 antibodies) were measured in the serum of participants who attended the 2011-2013 Pittsburgh Epidemiology of Diabetes Complications study follow-up examination (n=177, mean age 51 years, diabetes duration 43 years).

RESULTS

Prevalences of islet autoantibodies were: glutamic acid decarboxylase, 32%; insulinoma-associated protein 2, 22%; and zinc transporter-8, 4%. Positivity for each islet autoantibody was associated with older age at diabetes onset (glutamic acid decarboxylase antibodies, P=0.03; insulinoma-associated protein 2 antibodies, P=0.001; zinc transporter-8 antibodies, P<0.0001). Older age at onset was also associated with an increasing number of autoantibodies (P = 0.001). Glutamic acid decarboxylase antibody positivity was also associated with lower HbA_1c (P = 0.02), insulinoma-associated protein 2 antibody positivity was associated with lower prevalence of severe hypoglycaemic episodes (P=0.02) and both distal and autonomic neuropathy (P=0.04 for both), and zinc transporter-8 antibody positivity was associated with higher total and LDL cholesterol (P=0.01). No association between autoantibody positivity and C-peptide was observed.

CONCLUSIONS

The strong association between islet autoantibody positivity and older age at type 1 diabetes onset supports the hypothesis of a less aggressive, and thus more persistent, immune process in those with older age at onset. This observation suggests that there may be long-term persistence of heterogeneity in the underlying autoimmune process.

Effect of age at menarche on microvascular complications among women with Type 1 diabetes

AIM

To test the hypothesis that delayed menarche is associated with an increased microvascular complication risk among women with Type 1 diabetes.

METHODS

We studied the female participants of an ongoing prospective study of childhood-onset Type 1 diabetes diagnosed during the period 1950-1980. Of 325 women, we included data from 315 who had reached menarche by the study baseline (1986-1988) and who self-reported their age at menarche. Both cross-sectional and prospective analyses over the 25-year follow-up were used to assess the relationship of age at menarche with the prevalence, incidence and cumulative incidence of microvascular complications, comprising overt nephropathy, proliferative retinopathy and confirmed distal symmetric polyneuropathy.

RESULTS

In cross-sectional analyses at baseline, the odds of overt nephropathy increased 1.24 times (P=0.02) with each annual increase in age at menarche, and 3.2 times (P=0.009) in those with delayed menarche compared with women with normal menarche onset, after adjustment. Similarly, the cumulative incidence of overt nephropathy increased 1.16 times (P=0.01) with each older year of menarche and women with delayed menarche were at twofold increased risk of overt nephropathy (hazard ratio 2.30, P=0.001) compared with women with normal menarche onset. However, age at menarche was not significantly associated with either proliferative retinopathy or confirmed distal symmetric polyneuropathy after adjusting for covariates.

CONCLUSIONS

Age at menarche was significantly associated with the prevalence and cumulative incidence of overt nephropathy, but not with proliferative retinopathy or confirmed distal symmetric polyneuropathy in Type 1 diabetes. Women with delayed menarche may therefore be targeted for early screening and timely interventions to prevent the development of nephropathy.

Depressive symptoms and cerebral microvascular disease in adults with Type 1 diabetes mellitus

AIM

To assess the prevalence of, and risk factors for, depressive symptoms, comparing a sample of middle-aged adults with and without juvenile-onset Type 1 diabetes mellitus, and to determine if depressive symptoms were associated with white matter hyperintensity volume among those with Type 1 diabetes.

METHODS

Depressive symptoms and white matter hyperintensities were compared between adults (age range 30-65 years) with juvenile-onset Type 1 diabetes (n=130) and adults without Type 1 diabetes (n=133). The association of Type 1 diabetes with depression was computed before and after adjustment for white matter hyperintensities. Among the Type 1 diabetes group, the primary associations of interest were between depressive symptoms (Beck Depression Inventory score ≥10) and white matter hyperintensities (n=71), hyperglycaemia and physical activity. Associations between depressive symptoms and diabetes-related complications, cognitive impairment, smoking and self-reported disability were examined. Analyses were controlled for education, sex, age and antidepressant use.

RESULTS

Depressive symptoms were more prevalent among those with vs those without Type 1 diabetes (28% vs 3%; P<0.001). White matter hyperintensities explained 40% of the association of Type 1 diabetes with depressive symptoms, while Type 1 diabetes had a direct effect of 68% on depressive symptoms. Among those with Type 1 diabetes, depressive symptoms were related to white matter hyperintensity volume, a 16-year average HbA1c ≥58 mmol/mol (7.5%), and lower physical activity levels. Associations with other characteristics were not significant.

CONCLUSION

These findings suggest a cerebrovascular origin for depressive symptoms in adults with Type 1 diabetes, perhaps triggered by hyperglycaemia. Future longitudinal studies should investigate whether targeting hyperglycaemia and physical inactivity alleviates depressive symptoms, possibly by slowing the development of cerebral microvascular disease, in people with Type 1 diabetes.

Predictors of early renal function decline in adults with Type 1 diabetes: the Coronary Artery Calcification in Type 1 Diabetes and the Pittsburgh Epidemiology of Diabetes Complications studies

AIM

Diabetic kidney disease is one of the leading complications of Type 1 diabetes, but its prediction remains a challenge. We examined predictors of rapid decline in estimated GFR (eGFR) in two Type 1 diabetes cohorts: the Coronary Artery Calcification in Type 1 Diabetes (CACTI) and the Pittsburgh Epidemiology of Diabetes Complications (EDC).

METHODS

A select subset of participants (CACTI: n = 210 and EDC: n = 98) diagnosed before 17 years of age with Type 1 diabetes duration ≥ 7 years, and follow-up data on eGFR by CKD-EPI creatinine for up to 8 years were included in the analyses. Early renal function decline was defined as annual decline in eGFR ≥ 3 ml/min/1.73 m² , and normal age-related decline as eGFR ≤ 1 ml/min/1.73 m² . Parallel logistic regression models were constructed in the two cohorts.

RESULTS

Early renal function decline incidence was 36% in CACTI and 41% in EDC. In both cohorts, greater baseline eGFR (CACTI: OR 3.12, 95% CI 1.97-5.05; EDC: OR 1.92, 95% CI 1.17-3.15 per 10 ml/min/1.73 m² ) and log albumin-to-creatinine (ACR) (CACTI: OR 3.24, 95% CI 1.80-5.83; EDC: OR 1.87, 95% CI 1.18-2.96 per 1 unit) predicted greater odds of early renal function decline in fully adjusted models. Conversely, ACE inhibition predicted lower odds of early renal function decline in women in CACTI, but similar relationships were not observed in women in EDC.

CONCLUSIONS

A substantial proportion of people with Type 1 diabetes in the EDC and CACTI cohorts experienced early renal function decline over time. ACE inhibition appeared to be protective only in women in CACTI where the prevalence of its use was twofold higher compared with the EDC.

Glycaemic control modifies the haptoglobin 2 allele-conferred susceptibility to coronary artery disease in Type 1 diabetes

AIMS

We aimed to assess whether the association of the haptoglobin 2 allele with coronary artery disease is modified by glycaemic control in a prospective cohort study of individuals with childhood-onset Type 1 diabetes.

METHODS

Coronary artery disease events (death from coronary artery disease, confirmed myocardial infarction, stenosis ≥50%, revascularization) were assessed between 1986 and 2013 among 480 individuals with Type 1 diabetes (baseline age 28 years; diabetes duration 19 years). Better glycaemic control was defined as an updated mean HbA_1c during follow-up of <8% (64 mmol/mol).

RESULTS

In crude models, the incidence of coronary artery disease increased with the number of haptoglobin 2 alleles (hazard ratio 1.34, 95% CI 1.05-1.71). This association was more pronounced in those with better than in those with worse glycaemic control (P interaction = 0.05) and remained essentially unaltered after multivariable adjustments (hazard ratio 2.65, 95% CI 1.30-5.41 in those with better glycaemic control and hazard ratio 1.20, 95% CI 0.93-1.56 in those with worse glycaemic control).

CONCLUSIONS

These results suggest that, although better control may reduce the incidence of coronary artery disease in Type 1 diabetes, a residual risk related to the haptoglobin 2 allele remains.

The assessment of clinical distal symmetric polyneuropathy in type 1 diabetes: a comparison of methodologies from the Pittsburgh Epidemiology of Diabetes Complications Cohort

Distal symmetrical polyneuropathy (DSP) is the most common type of diabetic neuropathy, but often difficult to diagnose reliably. We evaluated the cross-sectional association between three point-of-care devices, Vibratron II, NC-stat(®), and Neurometer(®), and two clinical protocols, MNSI and monofilament, in identifying those with DSP, and/or amputation/ulcer/neuropathic pain (AUP), the two outcomes of major concern. This report presents data from 195 type 1 diabetic participants of the Epidemiology of Diabetes Complications (EDC) Study attending the 18-year examination (2004-2006). Participants with physician-diagnosed DSP, AUP or who were abnormal on the NC-stat, and the Vibratron II, MNSI, and monofilament were older (p<0.05) and had a longer duration of diabetes (p < 0.05). There was no difference by sex for DSP, AUP, or any testing modality, with the exception of NCstat (motor). The Vibratron II and MNSI showed the highest sensitivity for DSP (>87%) and AUP (>80%), whereas the monofilament had the highest specificity (98% DSP, 94% AUP) and positive predictive value (89% DSP, 47% AUP), but lowest sensitivity (20% DSP, 30% AUP). The MNSI also had the highest negative predictive value (83%) and Youden's Index (37%) and currently presents the single best combination of sensitivity and specificity of DSP in type 1 diabetes.

Risk factor associations with clinical distal symmetrical polyneuropathy and various neuropathy screening instruments and protocols in type 1 diabetes

OBJECTIVE

To determine whether DSP and neuropathy-assessment instruments used by non-physicians have similar risk factors.

RESEARCH DESIGN AND METHODS

analyses were cross-sectional (n=176).

RESULTS

risk factors were similar for DSP and screening devices.

CONCLUSIONS

these data support the clinical utility of neuropathy screening devices used by non-physician personnel.

In the absence of renal disease, 20 year mortality risk in type 1 diabetes is comparable to that of the general population: a report from the Pittsburgh Epidemiology of Diabetes Complications Study

AIMS/HYPOTHESIS

The FinnDiane Study has reported that mortality in type 1 diabetes is not increased over a 7 year follow-up in the absence of renal disease (RD). Using the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study population (n = 658) of childhood-onset type 1 diabetes (age <17 years), the present study sought to replicate and expand these findings to a 20 year follow-up (as of 1 January 2008) and examine cause of death by renal status.

METHODS

At baseline (1986-1988), mean age and duration of diabetes were 28 and 19 years, respectively. RD was defined as an albumin excretion rate ≥20 μg/min from multiple samples and grouped as microalbuminuria (MA; 20-200 μg/min), overt nephropathy (ON; >200 μg/min), or end stage renal disease (ESRD; dialysis or renal transplantation).

RESULTS

At baseline, 311 (47.3%) individuals had RD (MA 21.3%, ON 22.2% and ESRD 3.8%). During a median 20 year follow-up, there were 152 deaths (23.1%). Mortality was 6.2 (95% CI 5.2-7.2) times higher than expected, with standardised mortality ratios of 2.0 (1.2-2.8) for normoalbuminuria (NA); 6.4 (4.4-8.4) for MA; 12.5 (9.5-15.4) for ON; and 29.8 (16.8-42.9) for ESRD. Excluding those (n = 64) with NA who later progressed to RD, no significant excess mortality was observed in the remaining NA group (1.2, 0.5-1.9), whose deaths were largely unrelated to diabetes.

CONCLUSIONS/INTERPRETATION

These data confirm the importance of RD, including persistent microalbuminuria, as a marker of mortality risk and suggest that type 1 diabetes patients without renal disease achieve long-term survival comparable to the general population.

Temporal patterns in overweight and obesity in Type 1 diabetes

AIMS

Time trends in overweight and obesity in the general population have been well documented; however, temporal patterns in Type 1 diabetes (T1DM) have not been thoroughly investigated. We therefore assessed temporal patterns in overweight and obesity and predictors of weight change in 589 individuals from the Pittsburgh Epidemiology of Diabetes Complications Study, a cohort of childhood-onset T1DM.

METHODS

Participants were first seen in 1986-1988, when mean age and diabetes duration were 29 and 20 years, respectively, and biennially thereafter for 18 years. Overweight was defined as 25.0or=30.0 kg/m2.

RESULTS

At baseline, the prevalence of overweight and obesity were 28.6% and 3.4%, respectively. After 18 years' follow-up, the prevalence of overweight increased by 47% while the prevalence of obesity increased sevenfold. Seven per cent were on intensive insulin therapy (>or=3 insulin injections per day or on insulin pump) at baseline; by 2004-2007, this was 82%. Predictors of weight change were a higher baseline HbA1c, symptomatic autonomic neuropathy (inversely), overt nephropathy (inversely), and going onto intensive insulin therapy during follow-up.

CONCLUSIONS

These data demonstrate dramatic weight gain in T1DM and underscore the complexity of weight change in this disease.

Adiposity and mortality in type 1 diabetes

Background

In the general population, adiposity exhibits a J- or U-shaped relationship with mortality; however, in catabolic states this relationship is often inversely linear. We have recently documented an age-independent increase in overweight/obesity in the Pittsburgh Epidemiology of Diabetes Complications study (EDC) of type 1 diabetes (T1D). As intensified insulin therapy (IIT) may promote weight gain, the impact of weight gain in T1D is of importance. We therefore assessed the association of adiposity with mortality in 655 EDC participants during twenty years of follow-up.

Methods

Individuals were categorized as underweight (BMI <20), normal (20≤BMI<25), overweight (25≤BMI<30), or obese (BMI≥30). Cox models were constructed using BMI and covariates at baseline, updated means during follow-up, time-varying (reflecting most recent status), and change during adulthood as predictors of mortality.

Results

The prevalence of IIT (3+ insulin shots daily and/or pump) increased from 7% to 82%. Overweight increased 47%; obesity increased 7-fold. There were 146 deaths. In unadjusted models BMI (modeled continuously) demonstrated a quadratic relationship with mortality (p=0.002, <0.0001, <0.0001 for baseline, updated mean, and time-varying models, respectively). However, only in the time-varying model were the obese significantly different from the normal weight. while the baseline model revealed no differences by BMI category, in both the updated mean and time varying models, the underweight were at greater risk than the normal weight (p<0.0001 both models). The nonlinear relationship of adiposity with mortality remained after adjustment for diabetes complications, biological, or socioeconomic/lifestyle risk factors, with the exception of baseline socioeconomic/lifestyle risk factors where a linear association emerged. Adjustment for waist circumference eliminated the risk in the obese. Finally, weight gain during follow-up was protective.

Conclusion

The relationship of adiposity with mortality in T1D now appears to resemble that of the general population, albeit with a marked increased risk in those underweight.

Plasma and dietary vitamin E in relation to insulin secretion and sensitivity

AIM

In the Insulin Resistance and Atherosclerosis Study (IRAS), we have previously shown a protective effect of plasma alpha-tocopherol concentration against diabetes incidence among persons not taking vitamin E supplements. The biologic mechanism for such a protective effect could involve improvement in either insulin sensitivity (S(I)), insulin secretion or both. Thus, we examined vitamin E in relation to insulin secretion and S(I) among persons not taking vitamin E supplements.

METHODS

This analysis included 457 adults aged 40-69 years without a previous diabetes diagnosis or vitamin E supplement use at baseline and seen at the 5-year follow-up examination. Baseline nutrient intake was estimated from a validated 1-year food frequency questionnaire; plasma levels of alpha-tocopherol were also assessed. At follow up, a frequently sampled intravenous glucose tolerance test determined S(I), acute insulin response to glucose (AIR), and the disposition index (DI) was calculated as the sum of the log-transformed AIR and S(I) to reflect pancreatic compensation for insulin resistance.

RESULTS

In multivariable regression analyses, no relationship was observed for vitamin E intake and either S(I), AIR or DI. However, plasma alpha-tocopherol concentration was positively associated with log-transformed S(I) (beta= 0.27 +/- 0.09, p < 0.01) and DI (beta= 0.41 +/- 0.14, p < 0.01), but not with log-transformed AIR.

CONCLUSIONS

Plasma concentration of alpha-tocopherol may improve S(I) and pancreatic compensation for insulin resistance, although it does not seem to be related to acute insulin response.

Changes in glycaemic control and risk of coronary artery disease in type 1 diabetes mellitus: findings from the Pittsburgh Epidemiology of Diabetes Complications Study (EDC)

AIMS/HYPOTHESIS

To complete a comparative analysis of studies that have examined the relationship between glycaemia and cardiovascular disease (CVD)/coronary artery disease (CAD) and perform a prospective analysis of the effect of change in glycosylated Hb level on CAD risk in the Pittsburgh Epidemiology of Diabetes Complications Study (EDC) of childhood-onset type 1 diabetes mellitus (n = 469) over 16 years of two yearly follow-up.

METHODS

Measured values for HbA(1) and HbA(1c) from the EDC were converted to the DCCT-standard HbA(1c) for change analyses and the change in HbA(1c) was calculated (final HbA(1c) minus baseline HbA(1c)). CAD was defined as EDC-diagnosed angina, myocardial infarction, ischaemia, revascularisation or fatal CAD after medical record review.

RESULTS

The comparative analysis suggested that glycaemia may have a stronger effect on CAD in patients without, than in those with, albuminuria. In EDC, the change in HbA(1c) differed significantly between CAD cases (+0.62 +/- 1.8%) and non-cases (-0.09 +/- 1.9%) and was an independent predictor of CAD.

CONCLUSIONS/INTERPRETATION

Discrepant study results regarding the relationship of glycaemia with CVD/CAD may, in part, be related to the prevalence of renal disease. Measures of HbA(1c) change over time show a stronger association with CAD than baseline values.

The prospective association between adiponectin and coronary artery disease among individuals with type 1 diabetes. The Pittsburgh Epidemiology of Diabetes Complications Study

AIMS/HYPOTHESIS

Recent findings suggest the potential involvement of adiponectin in obesity, diabetes and cardiovascular disease. We assessed the prospective association between adiponectin concentration and coronary artery disease in individuals with type 1 diabetes.

METHODS

Participants were identified from the Pittsburgh Epidemiology of Diabetes Complications cohort, a prospective follow-up study of childhood-onset type 1 diabetes. At baseline, subjects had a mean age of 28 years, and a mean diabetes duration of 19 years. Cases (determined by physician-diagnosed angina, confirmed myocardial infraction, stenosis >or=50%, ischemic ECG or revascularization) were matched to the control subjects with respect to sex, age and diabetes duration. Samples and risk factors for analyses were identified from the earliest exam prior to incidence in cases. Sera and information on all covariates were available for 28 cases and 34 control subjects. Proportional hazards models were constructed including matching variables.

RESULTS

Compared with those in men, adiponectin concentrations were elevated in females (p=0.009) and among individuals with macroalbuminuria (p=0.04). In multivariable analyses (adjusting for standard risk factors as well as lipoprotein measurements determined by nuclear magnetic resonance spectroscopy, E-selectin or antioxidants), adiponectin inversely predicted the incidence of coronary artery disease (hazard ratio=0.37 per 1 SD increase, 95% CI 0.19-0.73, p=0.004).

CONCLUSIONS/INTERPRETATION

The results suggest that increased adiponectin concentration is prospectively associated with a lower risk of coronary artery disease type 1 diabetes. The potential of adiponectin determination as a useful marker of, and potential therapeutic target for, coronary artery disease prevention in type 1 diabetes should be further explored.

Nutrition and prevention of type 2 diabetes

In recent years, the prevalence of type 2 diabetes has increased alarmingly worldwide, giving diabetes the dimension of an epidemic. Striking parallel increases in the prevalence of obesity reflect the importance of body fatness as a contributing factor to diabetes incidence. Moreover, it has been estimated that up to 75% of the risk of type 2 diabetes is attributable to obesity. Recent clinical trials and observational epidemiologic studies demonstrate the efficacy of lifestyle changes, including decreased energy intake, decreased fat intake, and weight loss, as well as regular participation in physical activity, in improving insulin sensitivity (SI) and reducing the risk of diabetes. This review evaluates evidence of the effect of diet on insulin resistance, insulin secretion, and glucose tolerance, and reflects on directions for future work toward primary prevention of type 2 diabetes.

Tracing the Mediterranean diet through principal components and cluster analyses in the Greek population

OBJECTIVE

To identify dietary patterns, and their socio-demographic and lifestyle correlates in a large sample of Greek adults, and assess their adherence to the traditional Mediterranean diet.

DESIGN

Principal component (PC) analysis was used to identify dietary patterns among 28 034 participants of the Greek branch of the European Prospective Investigation into Cancer and Nutrition. Dietary information was collected through a validated, semiquantitative, food-frequency questionnaire. The extracted PCs were subsequently regressed on sociodemographic and lifestyle variables. Analyses were also performed to classify individuals with similar dietary behavior into clusters.

RESULTS

Four PCs were identified: PC1 resembled the Mediterranean diet, PC2 approximated a vegetarian diet with emphasis on seed oils, PC3 reflected a preference for sweets, and PC4 reflected a Western diet. PC1 and PC2 were positively associated with age, education, physical activity, and nonsmoking status. Females, in comparison to males, scored higher on PC1 but lower on PC2. Males, younger, more educated individuals, nonsmokers and residents of Greater Athens (Attica) scored higher on PC3. PC4 was associated with younger age, less education, and current smoking. In cluster analyses, cluster A contrasted clusters B and C in having much higher mean PC1- and PC2-scores and substantially lower PC3- and PC4-scores. PC1 and PC4 were, respectively, positively and inversely correlated with an a priori Mediterranean-diet score; PC2 and PC3 were unrelated to it.

CONCLUSION

The Mediterranean-like PC1-score as well as the vegetarian-like PC2 were higher among older, more educated people, and were associated with a healthier lifestyle than PC4, which reflected a Western-type diet. PC1 was strongly positively associated with an a priori Mediterranean-diet score.

Obesity and sedentary lifestyle: modifiable risk factors for prevention of type 2 diabetes

Over the past 25 years, the prevalence and incidence of type 2 diabetes have increased alarmingly worldwide and across all age, gender, and race/ethnic groups. The high economic costs, resulting from the numerous and severe complications of this disease, as well as the social burden associated with diabetes mellitus, have motivated the pursuit of prevention methods. Recently, clinical and observational studies have demonstrated the adverse effects of obesity and sedentary lifestyle, as well as the benefits of moderate weight loss and related behaviors, including increased levels of physical activity, in maintaining metabolic control and reducing the incidence of type 2 diabetes. The challenge remains to find ways to successfully deliver this message to the communities, and to evaluate the cost-effectiveness of the different delivery approaches.