Maternal BMI before pregnancy, maternal weight gain during pregnancy, and risk of persistent positivity for multiple diabetes-associated autoantibodies in children with the high-risk HLA genotype: the MIDIA study

Preventable Prenatal and Neonatal Risk Factors of Type 1 Diabetes in Childhood

Background

Childhood type 1 diabetes mellitus (T1DM) is an autoimmune disease which is increasing in incidence, but little is known about the events that trigger the autoimmune process. Most of the time, these processes begin in prenatal and natal periods; therefore, this study aimed to investigate the prenatal and neonatal risk factors of T1DM in childhood.

Methods

This case-control study has been performed on children with T1DM who referred to the 17^th Shahrivar children's hospital. The control group consisted of healthy siblings of the case group. Data were gathered using a form that included maternal and neonatal characteristics. Data were reported by descriptive statistics in SPSS 19. To investigate the effect of quantitative and qualitative variables on the development of T1DM, logistic regression and Chi-square tests were used, respectively.

Results

Birth weight, birth height, and maternal weight gain during pregnancy had a significant relationship with T1DM (odds ratio [OR] = 1.23, 2.57, and 1.14, respectively). In addition, there was a significant relationship between gestational hypertension (OR = 5.27), neonatal jaundice (OR = 3.42), cesarean section (OR = 2.06), and being non-first-born child (OR = 2.32) and T1DM. Also, premature rupture of membrane, maternal urinary tract infection, and nonexclusive breastfeeding had a significant association with T1DM (OR = 4.37, 3.94, and 2.30, respectively). There were no statistically significant differences between maternal age, sex, neonatal respiratory disease, prematurity, and neonatal infections and T1DM (P > 0.05).

Conclusions

Prenatal and neonatal risk factors can have a significant role in the occurrence of TIDM. Therefore, considering these risk factors can have a preventive effect on T1DM.

Early life programming of health and disease: the long-term consequences of obesity in pregnancy: a narrative review

The prevalence of overweight and obesity is rising in all parts of the world and among young women it presents a very clear danger during pregnancy. Women who are overweight or who gain excessive weight during pregnancy are at greater risk of complications in pregnancy and labour, and are more likely to lose their child to stillbirth, or themselves die during pregnancy. This narrative review considers the evidence that in addition to increasing risk of poor pregnancy outcomes, obesity has the capacity to programme fetuses to be at greater risk of cardiometabolic disorders later in life. An extensive body of evidence from prospective and retrospective cohorts, and record linkage studies demonstrates associations of maternal obesity and/or gestational diabetes with cardiovascular disease, type-1 and type-2 diabetes. Studies in animals suggest that these associations are underpinned by adaptations that occur in fetal life, which remodel the structures of major organs including the brain, kidney and pancreas. This article is protected by copyright. All rights reserved.

Pre-pregnancy body mass index in mothers, birth weight and the risk of type I diabetes in their offspring: A dose-response meta-analysis of cohort studies

BACKGROUND

The incidence of type I diabetes among children has increased significantly and the relationship between maternal pre-pregnancy Body Mass Index (BMI), Birth weight and risk of Type 1 diabetes in children (T1DMC) is controversial.

OBJECTIVE

This dose-response meta-analysis was performed to investigate the association between maternal Pre-Pregnancy Body-Mass Index, Birth Weight and the Risk of Childhood Type I Diabetes.

SEARCH STRATEGY

A comprehensive systematic search was conducted in MEDLINE/PubMed, SCOPUS, Cochrane, and Web of Science databases from inception to April 2019. Key search terms included "body mass index" OR "Birth weight" AND "Type 1 diabetes".

SELECTION CRITERIA

Peer-reviewed studies that reporting association between BMI or birth weight and type I diabetes in a retrospective or prospective study by appropriate estimates such as the hazard ratio (HR), risk ratio (RR), or odds ratio (OR) and the corresponding 95 % confidence intervals (CI).

DATA COLLECTION AND ANALYSIS

MOOSE guidelines were followed. Data were extracted by 2 researchers, independently. Combined hazard ratios (HRs) was evaluated by DerSimonian and Laird Random-effects model.

RESULTS

Two studies continuing four arms with 1,209,122 participants were eligible for pre-pregnancy BMI section meta-analysis and six studies were eligible for inclusion, providing 10,340,036 participants for birth weight section meta-analysis. Pooled results demonstrated a significant association between obesity and risk of T1DMC (HR: 1.30, 95 % CI: 1.16-1.46, I2 = 7%). The combined HR (95 % CI) showed lower risk of T1DMC in low birth weight infants (HR: 0.78, 95 % CI: 0.69-0.88, I2 = 0%) and higher risk of T1DMC in the high birth weight infants versus the normal category of birth weight (HR: 1.08, 95 % CI: 1.00-1.17, I2 = 31 %). There was a significant non-linear association between birth weight and risk of T1DMC in children (Coef =-0.00032, p = 0.001).

CONCLUSIONS AND RELEVANCE

This systematic review and meta-analysis identified high maternal BMI and High birth weight (HBW) increase risk of childhood T1DMC.

The influence of maternal body mass index, maternal diabetes mellitus, and maternal smoking during pregnancy on the risk of childhood-onset type 1 diabetes mellitus in the offspring: Systematic review and meta-analysis of observational studies

There is emerging evidence that events occurring before and shortly after birth may be important in determining the risk of childhood-onset type 1 diabetes mellitus (T1DM). We aimed to summarize and synthesize the associations between maternal body mass index (BMI), maternal diabetes mellitus (DM), and maternal smoking during pregnancy and the risk of childhood-onset T1DM in the offspring by performing a systematic review and meta-analysis of observational studies. A random effects model was used to generate the summary risk estimates. The PubMed and Web of Science databases were searched to identify relevant observational studies. Twenty one observational studies were included in the present meta-analysis. Compared with offspring of mothers with normal weight, offspring of women with overweight or obesity were at an increased risk of developing childhood-onset T1DM (overweight: relative risk [RR] 1.09, 95% confidence interval [CI], 1.03-1.15; obesity: RR 1.25, 95% CI, 1.16-1.34; per 5 kg m^-2 increase in BMI: RR 1.10, 95% CI, 1.06-1.13). No association was found for maternal underweight (RR 0.92, 95% CI, 0.75-1.13). Maternal DM was associated with an increased risk of childhood-onset T1DM (RR 3.26, 95% CI, 2.84-3.74). Regarding the type of maternal DM, the greatest risk of T1DM in the offspring appeared to be conferred by maternal T1DM (RR 4.46, 95% CI, 2.89-6.89), followed by maternal gestational diabetes mellitus (RR 1.66, 95% CI, 1.16-2.36), and lastly by maternal type 2 diabetes mellitus (RR 1.11, 95% CI, 0.69-1.80). Additional analysis of studies comparing maternal versus paternal T1DM within the same population revealed that offspring of fathers with T1DM had a 1.5 times higher risk of developing childhood-onset T1DM than offspring of mothers with T1DM (RR 9.58, 95% CI, 6.33-14.48 vs. RR 6.24, 95% CI, 5.52-7.07). Furthermore, a reduced risk of childhood-onset T1DM was observed in infants born to mothers who smoked during pregnancy compared with infants born to mothers who did not smoke during pregnancy (RR 0.79, 95% CI, 0.71-0.87). In summary, our findings add further evidence that early-life events or environmental factors may play a role in modulating infants' risk of developing T1DM later in life.

Patterns of Gestational Weight Gain in Women with Overweight or Obesity and Risk of Large for Gestational Age

OBJECTIVE

Timing of gestational weight gain (GWG) may influence perinatal outcomes differently. This study aimed to find associations of latent GWG patterns with risk of large for gestational age (LGA) in women with overweight or obesity.

METHODS

A total of 4,438 women with overweight or obesity were included in the analyses. Latent trajectories of GWG associated with LGA were identified by trajectory analysis. GWG, risk of LGA and early pregnancy factors were compared between these identified groups.

RESULTS

This study identified four distinct GWG trajectory groups associated with LGA, each group including, respectively, 78.6, 19.0, 1.4, and 0.9% of the participants. Group 1 presented a typical curve with lower GWG in early pregnancy and relatively higher GWG in mid- and late pregnancy. Women in group 2 showed sustained high GWG and high LGA prevalence than women in group 1 (48.24 vs. 21.56%, p < 0.0001). A catch-up in GWG after low weight gain did not result in significantly higher risk of LGA in group 3 compared to group 1. On the other hand, a rapid GWG in the first two-thirds of pregnancy followed by a strict weight control was associated with elevated risk of LGA in group 4 than group 1 (62.50 vs. 21.56%, p < 0.0001).

CONCLUSIONS

Women affected by overweight or obesity combined with high GWG in early mid-pregnancy were at elevated risk of LGA. Early clinical recognition of a poor GWG trajectory will enable early intervention in high-risk groups.

Paternal and maternal obesity but not gestational weight gain is associated with type 1 diabetes

Background

Our objective was to examine the associations of parental body mass index (BMI) and maternal gestational weight gain with childhood-onset type 1 diabetes. Comparing the associations of maternal and paternal BMI with type 1 diabetes in the offspring will provide further insight into the role of unmeasured confounding by characteristics linked to BMI in both parents.

Methods

We studied 132 331 children participating in the Norwegian Mother and Child Cohort Study (MoBa) and the Danish National Birth Cohort (DNBC) who were born between February 1998 and July 2009. Exposures of interest included parental BMI and maternal gestational weight gain obtained by maternal report. We used Cox-proportional hazards regression to examine the risk of type 1 diabetes (n=499 cases), which was ascertained by national childhood diabetes registers.

Results

The incidence of type 1 diabetes was 32.7 per 100 000 person-years in MoBa and 28.5 per 100 000 person-years in DNBC. Both maternal pre-pregnancy obesity, adjusted hazard ratio (HR) 1.41 [95% confidence interval (CI): 1.06, 1.89] and paternal obesity, adjusted HR 1.51 (95% CI: 1.11, 2.04), were associated with childhood-onset type 1 diabetes. The associations were similar after mutual adjustment. In contrast, maternal total gestational weight gain was not associated with childhood-onset type 1 diabetes, adjusted HR 1.00 (95% CI: 0.99, 1.02) per kilogram increase.

Conclusions

Our study suggests that the association between maternal obesity and childhood-onset type 1 diabetes is not likely explained by intrauterine mechanisms, but possibly rather by unknown environmental factors influencing BMI in the family.

Intrauterine growth restriction combined with a maternal high-fat diet increased adiposity and serum corticosterone levels in adult rat offspring

Intrauterine growth restriction (IUGR) and fetal exposure to a maternal high-fat diet (HFD) independently increase the risk of developing obesity in adulthood. Excess glucocorticoids increase obesity. We hypothesized that surgically induced IUGR combined with an HFD would increase adiposity and glucocorticoids more than in non-IUGR offspring combined with the same HFD, findings that would persist despite weaning to a regular diet. Non-IUGR (N) and IUGR (I) rat offspring from dams fed either regular rat chow (R) or an HFD (H) were weaned to either a regular rat chow or an HFD. For non-IUGR and IUGR rats, this study design resulted in three diet groups: offspring from dams fed a regular diet and weaned to a regular diet (NRR and IRR), offspring rats from dams fed an HFD and weaned to a regular diet (NHR and IHR) and offspring from dams fed an HFD and weaned to an HFD (NHH and IHH). Magnetic resonance imaging or fasting visceral and subcutaneous adipose tissue collection occurred at postnatal day 60. IHH male rats had greater adiposity than NHH males, findings that were only partly normalized by weaning to a regular chow. IHH male rats had a 10-fold increase in serum corticosterone levels. IHH female rats had increased adiposity and serum triglycerides. We conclude that IUGR combined with an HFD throughout life increased adiposity, glucocorticoids and triglycerides in a sex-specific manner. Our data suggest that one mechanism through which the perinatal environment programs increased adiposity in IHH male rats may be via increased systemic glucocorticoids.

Maternal obesity as a risk factor for early childhood type 1 diabetes: a nationwide, prospective, population-based case-control study

AIMS/HYPOTHESIS

Genetic and environmental factors are believed to cause type 1 diabetes. The aim of this study was to investigate the influence of maternal BMI and gestational weight gain on the subsequent risk of childhood type 1 diabetes.

METHODS

Children in the Swedish National Quality Register for Diabetes in Children were matched with control children from the Swedish Medical Birth Register. Children were included whose mothers had data available on BMI in early pregnancy and gestational weight gain, giving a total of 16,179 individuals: 3231 children with type 1 diabetes and 12,948 control children.

RESULTS

Mothers of children with type 1 diabetes were more likely to be obese (9% [n = 292/3231] vs 7.7% [n = 991/12,948]; p = 0.02) and/or have diabetes themselves (2.8% [n = 90/3231] vs 0.8% [n = 108/12,948]; p < 0.001) compared with mothers of control children. Gestational weight gain did not differ significantly between the two groups of mothers. In mothers without diabetes, maternal obesity was a significant risk factor for type 1 diabetes in the offspring (p = 0.04). A child had an increased risk of developing type 1 diabetes if the mother had been obese in early pregnancy (crude OR 1.20; 95% CI 1.05, 1.38; adjusted OR 1.18; 95% CI 1.02, 1.36). Among children with type 1 diabetes (n = 3231) there was a difference (p < 0.001) in age at onset in relation to the mother's BMI. Among children in the oldest age group (15-19 years), there were more mothers who had been underweight during pregnancy, while in the youngest age group (0-4 years) the pattern was reversed.

CONCLUSIONS/INTERPRETATION

Maternal obesity, in the absence of maternal diabetes, is a risk factor for type 1 diabetes in the offspring, and influences the age of onset of type 1 diabetes. This emphasises the importance of a normal maternal BMI to potentially decrease the incidence of type 1 diabetes.

Early life origin of type 1 diabetes

Type 1 diabetes (T1D) is perceived as a chronic immune-mediated disease with a subclinical prodromal period characterized by selective loss of insulin-producing beta cells in the pancreatic islets in genetically susceptible subjects. The incidence of T1D has increased manifold in most developed countries after World War II in parallel with a series of other immune-mediated diseases. T1D results from gene-environmental interactions. The appearance of disease-associated autoantibodies into the peripheral circulation is the first detectable sign of the initiation of the disease process leading to clinical T1D. The first autoantibodies may appear already before the age of 6 months and the seroconversion rate peaks during the second year of life. This implies that exogenous factors involved in the pathogenesis of T1D must be operative in early life, some of them most likely already during pregnancy. Here, we discuss putative endogenous factors that may contribute to the development of T1D during fetal and early postnatal life. Many environmental factors operative in early life have been implicated in the pathogenesis of T1D, but relatively few have been firmly confirmed.

Immunometabolism of human autoimmune diseases: from metabolites to extracellular vesicles

Immunometabolism focuses on the mechanisms regulating the impact of metabolism on lymphocyte activity and autoimmunity outbreak. The adipose tissue is long known to release adipokines, either pro- or anti-inflammatory factors bridging nutrition and immune function. More recently, adipocytes were discovered to also release extracellular vesicles (EVs) containing a plethora of biological molecules, including metabolites and microRNAs, which can regulate cell function/metabolism in distant tissues, suggesting that immune regulatory function by the adipose tissue may be far more complex than originally thought. Moreover, EVs were also identified as important mediators of immune cell-to-cell communication, adding a further microenvironmental mechanism of plasticity to fine-tune specific lymphocyte responses. This Review will first focus on the known mechanisms by which metabolism impacts immune function, presenting a systemic (nutrition and long-ranged adipokines) and a cellular point of view (metabolic pathway derangement in autoimmunity). It will then discuss the new discoveries concerning how EVs may act as nanometric vehicles integrating immune/metabolic responses at the level of the extracellular environment and affecting pathological processes.

Metabolic control of immune tolerance in health and autoimmunity

The filed that links immunity and metabolism is rapidly expanding. The adipose tissue, by secreting a series of immune regulators called adipokines, represents the common mediator linking metabolic processes and immune system functions. The dysregulation of adipokine secretion, occurring in obese individuals or in conditions of malnutrition or dietary restriction, affects the activity of immune cells resulting in inflammatory autoimmune responses or increased susceptibility to infectious diseases. Alterations of cell metabolism that characterize several autoimmune diseases strongly support the idea that the immune tolerance is also regulated by metabolic pathways. The comprehension of the molecular mechanisms underlying these alterations may lead to the development of novel therapeutic strategies to control immune cell differentiation and function in conditions of autoimmunity.

Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania

The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (<LOD) to 785ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. A multiple linear regression model revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.

Parturition dysfunction in obesity: time to target the pathobiology

Over a third of women of childbearing age in the United States are obese, and during pregnancy they are at increased risk for delayed labor onset and slow labor progress that often results in unplanned cesarean delivery. The biology behind this dysfunctional parturition is not well understood. Studies of obesity-induced changes in parturition physiology may facilitate approaches to optimize labor in obese women. In this review, we summarize known and proposed biologic effects of obesity on labor preparation, contraction/synchronization, and endurance, drawing on both clinical observation and experimental data. We present evidence from human and animal studies of interactions between obesity and parturition signaling in all elements of the birth process, including: delayed cervical ripening, prostaglandin insensitivity, amniotic membrane strengthening, decreased myometrial oxytocin receptor expression, decreased myocyte action potential initiation and contractility, decreased myocyte gap junction formation, and impaired myocyte neutralization of reactive oxygen species. We found convincing clinical data on the effect of obesity on labor initiation and successful delivery, but few studies on the underlying pathobiology. We suggest research opportunities and therapeutic interventions based on plausible biologic mechanisms.

Maternal overweight and obesity are associated with increased risk of type 1 diabetes in offspring of parents without diabetes regardless of ethnicity

AIMS/HYPOTHESIS

The incidence of type 1 diabetes in children is increasing in Sweden, as is the prevalence of maternal overweight/obesity. Therefore, the aim of this study was to investigate if maternal overweight/obesity increases the risk of type 1 diabetes in offspring of parents with and without diabetes, and of different ethnicities.

METHODS

The study cohort comprised 1,263,358 children, born in Sweden between 1992 and 2004. Children were followed from birth until diagnosis of type 1 diabetes, emigration, death or end of follow-up in 2009, whichever occurred first. First trimester maternal BMI was calculated (kg/m(2)). Poisson regression was used to calculate incidence rate ratios (IRRs) with 95% CI for type 1 diabetes in the offspring.

RESULTS

The risk of type 1 diabetes was increased in offspring of parents with any type of diabetes regardless of parental ethnicity. High first trimester maternal BMI was associated with increased risk of type 1 diabetes only in offspring of parents without diabetes (IRR 1.33 [95% CI 1.20, 1.48]).

CONCLUSIONS/INTERPRETATION

Increasing incidence of type 1 diabetes in children with non-diabetic parents may partly be explained by increasing prevalence of maternal overweight/obesity.

Environmental trigger(s) of type 1 diabetes: why so difficult to identify?

Type 1 diabetes (T1D) is one of the most common chronic diseases with childhood onset, and the disease has increased two- to fivefold over the past half century by as yet unknown means. T1D occurs when the body's immune system turns against itself so that, in a very specific and targeted way, it destroys the pancreatic β-cells. T1D results from poorly defined interactions between susceptibility genes and environmental determinants. In contrast to the rapid progress in finding T1D genes, identification and confirmation of environmental determinants remain a formidable challenge. This review article will focus on factors which have to be evaluated and decision to take before starting a new prospective cohort study. Considering all the large ongoing prospective studies, new and more conclusive data than that obtained so far should instead come from international collaboration on the ongoing cohort studies.

Is prepregnancy obesity associated with risk of cerebral palsy and epilepsy in children?

We conducted a retrospective cohort study to investigate the association between prepregnancy obesity in women and risk of cerebral palsy and epilepsy in their children using data from the South Carolina Medicaid program. The cohort included 83,901 maternal-child pairs; 100 cases of cerebral palsy were initially identified, followed by 53 cases that had at least 2 cerebral palsy diagnoses. For confirmed epilepsy, diagnosed on at least 5 occasions or by more than 1 provider, 83,472 observations were included with 338 cases. There was no association between maternal body mass index and risk of childhood epilepsy. A significant association between increasing maternal body mass index and any diagnosis of cerebral palsy was found, and morbid obesity was associated with increased risk of any and confirmed cerebral palsy. In conclusion, there appears to be an association of maternal body mass index with cerebral palsy, but there is no evidence to support an association with epilepsy.

Study protocol: differential effects of diet and physical activity based interventions in pregnancy on maternal and fetal outcomes--individual patient data (IPD) meta-analysis and health economic evaluation

BACKGROUND

Pregnant women who gain excess weight are at risk of complications during pregnancy and in the long term. Interventions based on diet and physical activity minimise gestational weight gain with varied effect on clinical outcomes. The effect of interventions on varied groups of women based on body mass index, age, ethnicity, socioeconomic status, parity, and underlying medical conditions is not clear. Our individual patient data (IPD) meta-analysis of randomised trials will assess the differential effect of diet- and physical activity-based interventions on maternal weight gain and pregnancy outcomes in clinically relevant subgroups of women.

METHODS/DESIGN

Randomised trials on diet and physical activity in pregnancy will be identified by searching the following databases: MEDLINE, EMBASE, BIOSIS, LILACS, Pascal, Science Citation Index, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, and Health Technology Assessment Database. Primary researchers of the identified trials are invited to join the International Weight Management in Pregnancy Collaborative Network and share their individual patient data. We will reanalyse each study separately and confirm the findings with the original authors. Then, for each intervention type and outcome, we will perform as appropriate either a one-step or a two-step IPD meta-analysis to obtain summary estimates of effects and 95% confidence intervals, for all women combined and for each subgroup of interest. The primary outcomes are gestational weight gain and composite adverse maternal and fetal outcomes. The difference in effects between subgroups will be estimated and between-study heterogeneity suitably quantified and explored. The potential for publication bias and availability bias in the IPD obtained will be investigated. We will conduct a model-based economic evaluation to assess the cost effectiveness of the interventions to manage weight gain in pregnancy and undertake a value of information analysis to inform future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2013: CRD42013003804.

Environmental determinants of type 1 diabetes: a role for overweight and insulin resistance

Rates of type 1 diabetes are rising globally, with a decreasing proportion of high-risk genotypes and twin concordance rates below 50%. Therefore, environmental factors such as viruses, nutrition and overweight have been examined as putative aetiological agents. The accelerator hypothesis proposes that overweight and insulin resistance are central to both type 1 and type 2 diabetes and may explain, in part, the rise in type 1 diabetes incidence. The temporal rise in body mass index at type 1 diabetes onset and the observation that pre-diabetic children are heavier and more insulin resistant than their peers suggests convergence of type 1 and type 2 diabetes phenotypes. The influence of insulin resistance may begin in utero, although the aetiological role of birthweight in type 1 diabetes remains unclear. Further research to elucidate the role of these modifiable risk factors in today's obesogenic environment may provide future potential for diabetes prevention.

Diagnosis and classification of autoimmune diabetes mellitus

Diabetes mellitus is increasing in prevalence worldwide. The economic costs and burden of the disease are considerable given the cardiovascular complications and co-morbidities that it may entail. Two major groups of diabetes mellitus have been defined, type 1, or immune-based, and type 2. In recent years, other subgroups have been described in-between these major groups. Correct classification of the disease is crucial in order to ascribe the most efficient preventive, diagnostic and treatment strategies for each patient. In the present review, we discuss the epidemiology, etiopathogenesis, diagnostic criteria and clinical classification of what is currently known as autoimmune diabetes. In addition, the other groups of diabetes mellitus will be regarded in relation to their pathogenesis and potential autoimmunity features.

Enterobius vermicularis and allergic conditions in Norwegian children

Studies investigating the association between Enterobius vermicularis and allergic conditions have shown conflicting results. This study was conducted to test for any such associations in Norwegian children. Parents were asked to answer questionnaires concerning their children's history of allergies, wheezing or eczema and pinworm infections. Current pinworm infections were diagnosed by microscopic examination of anal scotch tape samples. The data were analysed using logistic regression. Atopic eczema, allergy or wheezing was reported to be confirmed by a physician in 23% of the children (84/364). A possible association between current pinworm infections and food allergy was found, with 17·5% of children without food allergy testing positive for pinworms, compared to 36·8% of children with food allergy (odds ratio 2·9, 95% confidence interval 1·1-8·0). No association was found between past pinworm treatments and present atopic conditions. The association between current E. vermicularis infections and food allergy warrants further study.

Environmental determinants of islet autoimmunity (ENDIA): a pregnancy to early life cohort study in children at-risk of type 1 diabetes

BACKGROUND

The incidence of type 1 diabetes has increased worldwide, particularly in younger children and those with lower genetic susceptibility. These observations suggest factors in the modern environment promote pancreatic islet autoimmunity and destruction of insulin-producing beta cells. The Environmental Determinants of Islet Autoimmunity (ENDIA) Study is investigating candidate environmental exposures and gene-environment interactions that may contribute to the development of islet autoimmunity and type 1 diabetes.

METHODS/DESIGN

ENDIA is the only prospective pregnancy/birth cohort study in the Southern Hemisphere investigating the determinants of type 1 diabetes in at-risk children. The study will recruit 1,400 unborn infants or infants less than six months of age with a first-degree relative (i.e. mother, father or sibling) with type 1 diabetes, across five Australian states. Pregnant mothers/infants will be followed prospectively from early pregnancy through childhood to investigate relationships between genotype, the development of islet autoimmunity (and subsequently type 1 diabetes), and prenatal and postnatal environmental factors. ENDIA will evaluate the microbiome, nutrition, bodyweight/composition, metabolome-lipidome, insulin resistance, innate and adaptive immune function and viral infections. A systems biology approach will be used to integrate these data. Investigation will be by 3-monthly assessments of the mother during pregnancy, then 3-monthly assessments of the child until 24 months of age and 6-monthly thereafter. The primary outcome measure is persistent islet autoimmunity, defined as the presence of autoantibodies to one or more islet autoantigens on consecutive tests.

DISCUSSION

Defining gene-environment interactions that initiate and/or promote destruction of the insulin-producing beta cells in early life will inform approaches to primary prevention of type 1 diabetes. The strength of ENDIA is the prospective, comprehensive and frequent systems-wide profiling from early pregnancy through to early childhood, to capture dynamic environmental exposures that may shape the development of islet autoimmunity.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry ACTRN12613000794707.

An obesogenic diet during mouse pregnancy modifies maternal nutrient partitioning and the fetal growth trajectory

In developed societies, high-sugar and high-fat (HSHF) diets are now the norm and are increasing the rates of maternal obesity during pregnancy. In pregnant rodents, these diets lead to cardiovascular and metabolic dysfunction in their adult offspring, but the intrauterine mechanisms involved remain unknown. This study shows that, relative to standard chow, HSHF feeding throughout mouse pregnancy increases maternal adiposity (+30%, P<0.05) and reduces fetoplacental growth at d 16 (-10%, P<0.001). At d 19, however, HSHF diet group pup weight had normalized, despite the HSHF diet group placenta remaining small and morphologically compromised. This altered fetal growth trajectory was associated with enhanced placental glucose and amino acid transfer (+35%, P<0.001) and expression of their transporters (+40%, P<0.024). HSHF feeding also up-regulated placental expression of fatty acid transporter protein, metabolic signaling pathways (phosphoinositol 3-kinase and mitogen-activated protein kinase), and several growth regulatory imprinted genes (Igf2, Dlk1, Snrpn, Grb10, and H19) independently of changes in DNA methylation. Obesogenic diets during pregnancy, therefore, alter maternal nutrient partitioning, partly through changes in the placental phenotype, which helps to meet fetal nutrient demands for growth near term. However, by altering provision of specific nutrients, dietary-induced placental adaptations have important roles in programming development with health implications for the offspring in later life.

Maternal obesity, gestational weight gain and diet as determinants of offspring long term health

This review addresses the increasingly prolific literature from studies in man and animals suggesting that maternal obesity, a diet rich in calories or excess gestational weight gain may, through perturbation of the intrauterine environment, lead to lifelong risk of obesity and related disorders in the child. In addressing maternal- child obesity relationships it remains a challenge to distinguish the influence of the intrauterine environment from the contribution of shared genetic traits, and to adequately adjust for postnatal determinants of childhood obesity. Studies in genetically identical rodents convincingly show that maternal obesity, as well as elements of a hypercalorific diet can permanently influence offspring risk of obesity, and are these are supported by studies in larger mammals. Importantly, dissection of the mechanism in animals has led to description of novel interactive pathways between maternal environment and fetus which are amenable to investigation in humans.

Enterobius vermicularis and risk factors in healthy Norwegian children

BACKGROUND

The prevalence of Enterobius vermicularis in neighboring countries of Norway show large variation. The goal of this study was to investigate the prevalence among Norwegian children and possible risk factors.

METHODS

The children were participants in "Environmental Triggers of Type 1 Diabetes: the MIDIA study." The study involved 2 groups with different genetic risks of type 1 diabetes: A high-risk group carries the Human Leukocyte Antigen genotype conferring the highest risk for type 1 diabetes and a nonhigh-risk group consisting of children without this genotype. Scotch tape samples were collected on 3 consecutive days and examined by light microscopy.

RESULTS

A total of 18% (72/395) of children were positive for E. vermicularis. The highest prevalence (34%) was in children 6-11 years of age. Only 2 children were prior known positives. Increased number of siblings was linked to more infections, and there were fewer infections in the children with the high-risk genotype.

CONCLUSION

E. vermicularis is a common parasite in Norwegian children. The likelihood of E. vermicularis infection depends on family size and prevalence increases with age. The reduced number of infections in the children carrying the high-risk genotype for type 1 diabetes is intriguing and should be investigated further.

Serum long chain n-3 fatty acids (EPA and DHA) in the pregnant mother are independent of risk of type 1 diabetes in the offspring

BACKGROUND

This article aims to study whether higher proportions of the long chain n-3 fatty acids eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in the phospholipid fraction of serum samples in pregnancy were associated with a lower risk of childhood onset type 1 diabetes in the offspring.

METHODS

In a prospective cohort of nearly 30 000 pregnant women who gave birth in Norway during 1992-1994, we analysed serum samples from 89 women whose child developed type 1 diabetes and was included in the nationwide Norwegian Childhood Diabetes Registry and 125 randomly selected women whose child did not develop type 1 diabetes before 15 years of age. Specific fatty acids were expressed as the proportion of total fatty acids (g/100 g) in the phospholipid fraction in serum analysed using solid phase extraction and gas chromatography with flame ionization detection.

RESULTS

There was no significant association between EPA or DHA in maternal serum and risk of type 1 diabetes in the offspring. Odds ratio (OR) for upper versus lower quartile of EPA was 0.75 [95% confidence interval (CI) 0.34-1.65], test for trend p = 0.4, and for DHA OR = 0.71 (95% CI 0.33-1.53), test for trend p = 0.6. No significant association was found for the sum of n-3 fatty acids, or for n-6/n-3 ratio in the mother with risk of type 1 diabetes in the offspring.

CONCLUSIONS

Our data did not support the hypothesis that higher proportions of maternal EPA or DHA during pregnancy are associated with a lower risk of type 1 diabetes in the offspring.

Excessive early gestational weight gain and risk of gestational diabetes mellitus in nulliparous women

OBJECTIVE

To estimate whether there is an association between excessive early gestational weight gain and the development of gestational diabetes mellitus (GDM) and excessive fetal growth.

METHODS

This is a secondary analysis of a randomized controlled trial of vitamins C and E in nulliparous low-risk women. Maternal weight gain from prepregnancy (self-reported) to 15-18 weeks of gestation was measured, and expected gestational weight gain was determined using the Institute of Medicine 2009 guidelines for each prepregnancy body mass index category. Excessive early gestational weight gain was defined as gestational weight gain greater than the upper range of the Institute of Medicine guidelines. Rates of GDM, birth weight greater than 4,000 g, and large for gestational age (LGA, birth weight 90 percentile or higher) were calculated and compared between women with excessive early gestational weight gain and early nonexcessive gestational weight gain (within or below Institute of Medicine guidelines).

RESULTS

A total of 7,985 women were studied. Excessive early gestational weight gain occurred in 47.5% of women. Ninety-three percent of women with excessive early gestational weight gain had total gestational weight gain greater than Institute of Medicine guidelines. In contrast, only 55% of women with nonexcessive early gestational weight gain had total gestational weight gain greater than Institute of Medicine guidelines (P<.001). Rates of GDM, LGA, and birth weight greater than 4,000 g were higher in women with excessive early gestational weight gain.

CONCLUSION

In our population, excessive early gestational weight gain occurred in 93% of women who had total gestational weight gain greater than the Institute of Medicine guidelines. In low-risk nulliparous women, excessive early gestational weight gain is associated with the development of GDM and excessive fetal growth.

LEVEL OF EVIDENCE

II.

Gestational weight gain: influences on the long-term health of the child

PURPOSE OF REVIEW

To address the recent evidence which suggests that inappropriate gestational weight gain (GWG) may have consequences that extend to the longer term health of the child.

RECENT FINDINGS

Inadequate GWG is associated with low birthweight, and excessive GWG to delivery of large for gestational age infants . Recent studies report relationships between excessive GWG and neonatal adiposity, and with childhood and adult obesity. These appear to be independent of confounders such as socioeconomic status and a shared family environment, or hereditary traits for obesity, supporting the 'developmental origins of disease' hypothesis.

SUMMARY

Because of periods of developmental plasticity, the early life metabolic environment may contribute to the risk of metabolic and cardiovascular disease in later life. The mechanisms which explain the relationships between maternal GWG and later life obesity remain unknown. Large, well conducted, intervention randomized controlled trials in pregnant women are required to address relationships between GWG and offspring risk of disease, including characterization of potential mediators. These should lead to more targeted and effective intervention strategies.

Prenatal care: touching the future

The provision of preconception and prenatal care is a critical and time-honored role for family physicians. It could even be termed the first preventive care a human being receives. It has been suggested by some studies that, because of the continuity of care that is considered a cornerstone of family practice, family physicians provide prenatal care that may improve birth outcome. Although prenatal care is acknowledged as important for a healthy pregnancy and delivery, there is debate regarding the true efficacy of prenatal care.

Relationship of maternal weight status and weight gain rate during pregnancy to the development of advanced beta cell autoimmunity in the offspring: a prospective birth cohort study

OBJECTIVE

This study set out to examine how maternal initial body mass index (BMI) and weight gain during pregnancy associate with advanced beta cell autoimmunity in the offspring.

SUBJECTS

A population-based birth cohort of 4093 children with increased human leukocyte antigen (HLA)-conferred susceptibility to type 1 diabetes (T1D) and their mothers were recruited between 1997 and 2002 in two university hospital regions in Finland.

METHODS

The children were monitored for T1D-associated autoantibodies at 3- to 12-month intervals. Advanced beta cell autoimmunity was defined as repeated positivity for islet cell antibodies and at least one of the other three autoantibodies (antibodies to insulin, glutamate decarboxylase and islet antigen 2). Mothers were asked to record the results of the weight measurements during their first and last visits to the antenatal clinic. The initial BMI and weight gain rate were calculated for each woman.

RESULTS

Altogether, 175 children developed advanced beta cell autoimmunity or T1D during the follow-up. Maternal BMI before pregnancy or weight gain during pregnancy was not associated with the end-point. Maternal vocational education was associated with child's smaller risk of developing advanced beta cell autoimmunity.

The epidemic of type 1 diabetes: what is it telling us?

PURPOSE OF REVIEW

Type 1 diabetes (T1D) is an autoimmune disorder which affects millions around the world. The incidence of T1D in children is increasing worldwide at a rate that cannot be explained by genetics alone. This review explores the recent research regarding possible causes of this epidemic.

RECENT FINDINGS

Investigation into T1D epidemiology has recently focused on several hypotheses. These theories include the role of infections, early childhood diet, vitamin D exposure, environmental pollutants, increased height velocity, obesity, and insulin resistance in the risk for T1D. Over the past year, the evidence has strengthened for early childhood infections, dietary proteins, and insulin resistance as risk factors for T1D, but not for vitamin D exposure or environmental pollutants.

SUMMARY

Investigation into the source of the current epidemic of T1D has shed light on several possible causes, but has not provided definitive answers, yet.

Interventions during pregnancy to reduce excessive gestational weight gain: a systematic review assessing current clinical evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system

BACKGROUND

  Excessive weight gain during pregnancy is common in developed countries and increases the risk of complications during pregnancy, delivery and the postpartum period, which can affect both maternal and fetal outcome. Interventions to reduce excessive gestational weight gain have previously not been systematically evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

OBJECTIVES

  To determine whether published trials of interventions to reduce excessive gestational weight gain are of sufficient quality and provide sufficient data to enable evidence-based recommendations to be developed for clinical practice in antenatal care.

SEARCH STRATEGY

  A literature search was conducted in the scientific databases PubMed, Cochrane Library, Cinhal and Pedro, and the reference lists of relevant articles were reviewed. The literature search was concluded on 15 August 2009.

SELECTION CRITERIA

  All randomised controlled trials (RCTs) were considered for inclusion. As the number of published RCTs was limited, we also considered for inclusion all nonrandomised intervention studies that included a control group. Systematic reviews were examined to identify additional original studies.

DATA COLLECTION AND ANALYSIS

  Two reviewers independently assessed the quality of the methods and results of all included articles. Extracted data were classified using the GRADE system.

MAIN RESULTS

  Four intervention studies with a randomised controlled design and four intervention trials with a nonrandomised controlled design met the inclusion criteria. As a consequence of important limitations in study design, inconsistency and lack of directness, the overall quality of evidence was judged to be very low using the GRADE system.

AUTHORS' CONCLUSIONS

  The results of published intervention trials are of insufficient quality to enable evidence-based recommendations to be developed for clinical practice in antenatal care.

Maternal age at birth and childhood type 1 diabetes: a pooled analysis of 30 observational studies

OBJECTIVE

The aim if the study was to investigate whether children born to older mothers have an increased risk of type 1 diabetes by performing a pooled analysis of previous studies using individual patient data to adjust for recognized confounders.

RESEARCH DESIGN AND METHODS

Relevant studies published before June 2009 were identified from MEDLINE, Web of Science, and EMBASE. Authors of studies were contacted and asked to provide individual patient data or conduct prespecified analyses. Risk estimates of type 1 diabetes by maternal age were calculated for each study, before and after adjustment for potential confounders. Meta-analysis techniques were used to derive combined odds ratios and to investigate heterogeneity among studies.

RESULTS

Data were available for 5 cohort and 25 case-control studies, including 14,724 cases of type 1 diabetes. Overall, there was, on average, a 5% (95% CI 2-9) increase in childhood type 1 diabetes odds per 5-year increase in maternal age (P = 0.006), but there was heterogeneity among studies (heterogeneity I(2) = 70%). In studies with a low risk of bias, there was a more marked increase in diabetes odds of 10% per 5-year increase in maternal age. Adjustments for potential confounders little altered these estimates.

CONCLUSIONS

There was evidence of a weak but significant linear increase in the risk of childhood type 1 diabetes across the range of maternal ages, but the magnitude of association varied between studies. A very small percentage of the increase in the incidence of childhood type 1 diabetes in recent years could be explained by increases in maternal age.