Early postnatal growth in children with HLA-conferred susceptibility to type 1 diabetes

Childhood Height Growth Rate Association With the Risk of Islet Autoimmunity and Development of Type 1 Diabetes

CONTEXT

Rapid growth has been suggested to promote islet autoimmunity and progression to type 1 diabetes (T1D). Childhood growth has not been analyzed separately from the infant growth period in most previous studies, but it may have distinct features due to differences between the stages of development.

OBJECTIVE

We aimed to analyze the association of childhood growth with development of islet autoimmunity and progression to T1D diagnosis in children 1 to 8 years of age.

METHODS

Longitudinal data of childhood growth and development of islet autoimmunity and T1D were analyzed in a prospective cohort study including 10 145 children from Finland, Germany, Sweden, and the United States, 1-8 years of age with at least 3 height and weight measurements and at least 1 measurement of islet autoantibodies. The primary outcome was the appearance of islet autoimmunity and progression from islet autoimmunity to T1D.

RESULTS

Rapid increase in height (cm/year) was associated with increased risk of seroconversion to glutamic acid decarboxylase autoantibody, insulin autoantibody, or insulinoma-like antigen-2 autoantibody (hazard ratio [HR] = 1.26 [95% CI = 1.05, 1.51] for 1-3 years of age and HR = 1.48 [95% CI = 1.28, 1.73] for >3 years of age). Furthermore, height rate was positively associated with development of T1D (HR = 1.80 [95% CI = 1.15, 2.81]) in the analyses from seroconversion with insulin autoantibody to diabetes.

CONCLUSION

Rapid height growth rate in childhood is associated with increased risk of islet autoimmunity and progression to T1D. Further work is needed to investigate the biological mechanism that may explain this association.

Growth in Children with HLA-Conferred Susceptibility to Type 1 Diabetes

The incidence of type 1 diabetes (T1D) is increasing throughout the world. This trend may be explained by the accelerator hypothesis. Our study investigated growth, its biochemical markers, and their associations with the development of diabetes-associated autoantibodies (DAAB) in 219 children with genetic risk for T1D. Subjects were divided into risk groups based on their human leukocyte antigen genotype. Children in the moderate- to high-risk group were significantly taller when corrected to mid-parental height and had a lower insulin-like growth factor 1 (IGF-1)/IGF-1 binding protein (IGFBP-3) molar ratio than those in the low-risk group (corrected height standard deviation score 0.22±0.93 vs. -0.04±0.84, P<0.05; molar ratio 0.199±0.035 vs. 0.211+0.039, P<0.05). Children with DAAB tended to be taller and to have a higher body mass index than those with no DAAB. Our results suggest that the accelerator hypothesis explaining the increasing incidence of T1D may not solely be dependent on environmental factors, but could be partially genetically determined.

The High-Risk Type 1 Diabetes HLA-DR and HLA-DQ Polymorphisms Are Differentially Associated With Growth and IGF-I Levels in Infancy: The Cambridge Baby Growth Study

OBJECTIVE

This study explored the link between HLA polymorphisms that predispose to type 1 diabetes and birth size, infancy growth, and/or circulating IGF-I in a general population-based birth cohort.

RESEARCH DESIGN AND METHODS

The Cambridge Baby Growth Study is a prospective observational birth cohort study that recruited 2,229 newborns for follow-up in infancy. Of these, 612 children had DNA available for genotyping single nucleotide polymorphisms in the HLA region that capture the highest risk of type 1 diabetes: rs17426593 for DR4, rs2187668 for DR3, and rs7454108 for DQ8. Multivariate linear regression models at critical ages (cross-sectional) and mixed-effects models (longitudinal) were performed under additive genetic effects to test for associations between HLA polymorphisms and infancy weight, length, skinfold thickness (indicator of adiposity), and concentrations of IGF-I and IGF-binding protein-3 (IGFBP-3).

RESULTS

In longitudinal models, the minor allele of rs2187668 tagging DR3 was associated with faster linear growth (P = 0.007), which was more pronounced in boys (P = 3 × 10^-7) than girls (P = 0.07), and was also associated with increasing IGF-I (P = 0.002) and IGFBP-3 (P = 0.003) concentrations in infancy. Cross-sectionally, the minor alleles of rs7454108 tagging DQ8 and rs17426593 tagging DR4 were associated with lower IGF-I concentrations at age 12 months (P = 0.003) and greater skinfold thickness at age 24 months (P = 0.003), respectively.

CONCLUSIONS

The variable associations of DR4, DR3, and DQ8 alleles with growth measures and IGF-I levels in infants from the general population could explain the heterogeneous growth trajectories observed in genetically at-risk cohorts. These findings could suggest distinct mechanisms involving endocrine pathways related to the HLA-conferred type 1 diabetes risk.

Allergy-Related Symptoms Are Poorly Predicted by IgE and Skin Prick Testing in Early Life

INTRODUCTION

In childhood, the so-called allergic march involves progression from IgE sensitization to allergy-related symptoms. Both IgE sensitization and relevant clinical symptoms are required for the diagnosis of allergy, but concordance between test results and clinical symptoms varies greatly, creating challenges for the diagnostics and for the prediction of outcomes. We assessed the prevalence of IgE sensitization and allergy symptoms, concordance between 2 IgE sensitization testing methods, and predictive value of these tests in relation to clinical symptoms in young Finnish children.

METHODS

The current study included 2 series of children: a birth cohort, in which the participants were followed prospectively from birth up to 3 years, and a young children cohort observed from 3 to 5 years of age. They were regularly monitored for sensitization by measuring serum allergen-specific IgEs (sIgEs) and performing skin prick tests (SPTs). The emergence of atopic dermatitis, wheezing, and symptoms associated with food allergies was recorded.

RESULTS

Over the first 5 years of life, the prevalence of sIgE sensitization was 46%, while it was 36% for positive SPTs. Disease prevalence was 26% for atopic dermatitis, 25% for wheezing, and 19% for symptoms associated with food allergies. Concordance between sIgE and SPT results was good for aeroallergens, but poor for dietary allergens. The association between clinical symptoms and sensitization was stronger at 5 years than at 3 years of age. The proportion of children with concordant combinations of allergy symptoms and sensitization markers in contrast to those with discordant combinations increased from 3 to 5 years.

CONCLUSION

In early childhood, testing for IgE sensitization predicts allergy-related symptoms in an age-dependent manner, but not particularly well. Tests predict symptoms caused by aeroallergens clearly better than those caused by dietary allergens. The clinical relevance of sensitization testing in early life is therefore limited in the prediction of true allergy.

Growth rate of coeliac children is compromised before the onset of the disease

INTRODUCTION

Growth impairment has often been described in children who develop coeliac disease (CD). Based on data from the multicentre, longitudinal PreventCD study, we analysed the growth patterns of infants at genetic risk of CD, comparing those who developed CD by 6 years of age (CD 'cases', 113 infants) versus those who did not develop CD by 6 years (no CD 'controls', 831 infants).

METHODS

Weight and length/height were measured using a longitudinal protocol. Raw measurements were standardised, computing z-scores for length/height and weight; a linear mixed model was fitted to the data in order to compare the rate of growth in the two cohorts.

RESULTS

Neither cases nor controls had significant growth failure. However, when the mean z-scores for weight and height were analysed, there was a difference between the two groups starting at fourth month of life. When the growth pattern in the first year was analysed longitudinally using mixed models, it emerged that children who develop CD had a significantly lower growth rate in weight z-score (-0.028/month; 95% CI -0.038 to -0.017; p<0.001) and in length/height z-score (-0.018/month; 95% CI -0.031 to -0.005; p=0.008) than those who do not develop CD. When the whole follow-up period was analysed (0-6 years), differences between groups in both weight and length/height z-scores were confirmed.

CONCLUSION

The growth of children at risk of CD rarely fell below 'clinical standards'. However, growth rate was significantly lower in cases than in controls. Our data suggest that peculiar pathways of growth are present in children who develop CD, long before any clinical or serological signs of the disease appear.

Growth hormone and insulin-like growth factor-I axis in type 1 diabetes

The precise mechanisms relating type 1 diabetes (T1D) and poor glycemic control to the axis of growth hormone (GH), insulin like growth factor- I (IGF-I), and IGF binding protein-3 (IGFBP-3) remain to be definitively determined. GH resistance with low IGF-I as is frequently seen in patients with T1D is often related to portal hypoinsulization, and lack of upregulation of GH receptors. There are conflicting reports of the effect of a dysregulated GH/IGF-I axis on height in children and adolescents with T1D, as well as on chronic complications. This brief review discusses some of the interactions between the GH/IGF-I axis and T1D pathology, and vice-versa.

Early growth in children with coeliac disease: a cohort study

OBJECTIVES

We aimed to study growth during the first 2 years of life in children later diagnosed with coeliac disease compared with children without, in a time with changing epidemiology and improved diagnostics.

DESIGN

A prospective population-based pregnancy cohort study.

SETTING

The nationwide Norwegian Mother and Child Cohort Study.

PATIENTS

58 675 children born between 2000 and 2009 with prospectively collected growth data. Coeliac disease was identified through combined data from questionnaires and the Norwegian Patient Register.

MAIN OUTCOME MEASURES

The differences in height and weight at age 0, 3, 6, 8, 12, 15-18 and 24 months using internally standardised age and gender-specific z-scores. Linear regression and mixed models were used.

RESULTS

During a median follow-up of 8.6 years (range 4.6-14.2), 440 children (0.8%) were diagnosed with coeliac disease at a mean age of 4.4 years (range 1.5-8.5). Children with coeliac disease had significantly lower z-scores for height from 12 months (-0.09 standard deviation scores (SDS), 95% CI -0.18 to -0.01) and weight from 15 to 18 months of life (-0.09 SDS, 95% CI -0.18 to -0.01) compared with cohort controls. The longitudinal analysis from 0 to 24 months yielded a significant reduction in height z-score per year (-0.07 SDS, 95% CI -0.13 to -0.01) but not for weight among children with coeliac disease. Excluding children diagnosed before age 2 years gave similar results.

CONCLUSIONS

This study indicates that growth retardation in children later diagnosed with coeliac disease commonly starts at 12 months of age, and precedes clinical symptoms that usually bring the suspicion of diagnosis.

Modulation of type 1 and type 2 diabetes risk by the intestinal microbiome

The prevalence of type 1 and type 2 diabetes have both risen dramatically over the last 50 years. Recent findings point towards the gut microbiota as a potential contributor to these trends. The hundred trillion bacteria residing in the mammalian gut have established a symbiotic relation with their host and influence many aspects of host metabolism, physiology, and immunity. In this review, we examine recent data linking gut microbiome composition and function to anti-pancreatic immunity, insulin-resistance, and obesity. Studies in rodents and human longitudinal studies suggest that an altered gut microbiome characterized by lower diversity and resilience is associated with type 1 and type 2 diabetes. Through its metabolites and enzymatic arsenal, the microbiota shape host metabolism, energy extracted from the diet and contribute to the normal development of the immune system and to tissue inflammation. Increasing evidence underscores the importance of the maternal microbiome, the gestational environment and the conditions of newborn delivery in establishing the gut microbiota of the offspring. Perturbations of the maternal microbiome during gestation, or that of the offspring during early infant development may promote a pro-inflammatory environment conducive to the development of autoimmunity and metabolic disturbance. Collectively the findings reviewed herein underscore the need for mechanistic investigations in rodent models and in human studies to better define the relationships between microbial and host inflammatory activity in diabetes, and to evaluate the potential of microbe-derived therapeutics in the prevention and treatment of both forms of diabetes.

Circulating IGF1 and IGFBP3 in relation to the development of β-cell autoimmunity in young children

OBJECTIVE

This study aimed at investigating the role of IGF1 and IGF binding protein 3 (IGFBP3) in the development of β-cell autoimmunity.

METHODS

Five hundred and sixty-three subjects with HLA-conferred susceptibility to type 1 diabetes (T1D) were monitored for signs of seroconversion to positivity for insulin and/or GAD, IA2, and zinc transporter 8 autoantibodies by the age of 3 years. In 40 subjects who developed at least one autoantibody, IGF1 and IGFBP3 plasma concentrations were measured and compared with 80 control subjects who remained negative for autoantibodies, and were matched for age, sex, country of origin, and HLA genotype. The increments of IGF1, IGFBP3, and IGF1/IGFBP3 molar ratio before and after seroconverison were compared with corresponding time intervals in controls.

RESULTS

The IGF1 concentrations at the age of 12 months and the IGF1/IGFBP3 ratio at the age of 24 months were lower in the autoantibody-positive children (P<0.05). The increase in circulating IGFBP3 was significantly higher in the autoantibody-positive children before seroconversion than in the corresponding time intervals in controls (0.43 mg/l; 95% CI 0.29-0.56 vs 0.22 mg/l; 95% CI 0.10-0.34 mg/l; P<0.01). Children carrying the high-risk HLA genotype had lower plasma IGF1 and IGFBP3 concentrations at the age of 24 months than those with low-risk genotypes (P<0.05 and < 0.01 respectively).

CONCLUSIONS

Circulating IGF1 and IGFBP3 appear to have a role in early development of β-cell autoimmunity. The decreased IGF1 concentrations in children with the high-risk HLA genotype may contribute to the reduced growth previously described in such children.

The intestinal microbiome in type 1 diabetes

Few concepts in recent years have garnered more disease research attention than that of the intestinal (i.e. 'gut') microbiome. This emerging interest has included investigations of the microbiome's role in the pathogenesis of a variety of autoimmune disorders, including type 1 diabetes (T1D). Indeed, a growing number of recent studies of patients with T1D or at varying levels of risk for this disease, as well as in animal models of the disorder, lend increasing support to the notion that alterations in the microbiome precede T1D onset. Herein, we review these investigations, examining the mechanisms by which the microbiome may influence T1D development and explore how multi-disciplinary analysis of the microbiome and the host immune response may provide novel biomarkers and therapeutic options for prevention of T1D.