Perinatal risk factors for type 1 diabetes revisited: a population-based register study

Association between perinatal and obstetric factors and early age at diagnosis of type 1 diabetes mellitus: a cohort study

OBJECTIVES

To evaluate the association between perinatal and obstetric factors as potential triggers for the early onset of T1DM.

METHODS

This was a retrospective cohort study enrolling 409 patients diagnosed with T1DM, in Bauru, São Paulo, Brazil, from 1981 to 2023. Data were retrieved from medical records, regarding sociodemographic parameters as age, sex, ethnicity, and socioeconomic status. Perinatal and obstetric factors as delivery type, gestational age, filiation order, length of exclusive breastfeeding, maternal age, maternal and fetal blood types, and occurrence of maternal gestational diabetes were also analyzed. An adapted survival analysis was employed to gauge the impact of each assessed variable at the age of T1DM diagnosis.

RESULTS

The median age of T1DM diagnosis was 10.3 years with an interquartile range between 6.4 and 15.5 years. Delivery type and filiation order were the only factors statistically significantly associated with an early age at T1DM diagnosis. Patients who were born through cesarean section and who were firstborns showed a 28.6 and 18.0 % lower age at T1DM diagnosis, respectively, compared to those born through vaginal delivery and those that were nonfirstborns.

CONCLUSIONS

Being born by cesarean section and being firstborn showed to be statistically significant factors to determine an early T1DM diagnosis.

Gestational age at birth and type 1 diabetes in childhood and young adulthood: a nationwide register study in Finland, Norway and Sweden

AIMS/HYPOTHESIS

Children and adults born preterm have an increased risk of type 1 diabetes. However, there is limited information on risk patterns across the full range of gestational ages, especially after extremely preterm birth (23-27 weeks of gestation). We investigated the risk of type 1 diabetes in childhood and young adulthood across the full range of length of gestation at birth.

METHODS

Data were obtained from national registers in Finland, Norway and Sweden. In each country, information on study participants and gestational age was collected from the Medical Birth Registers, information on type 1 diabetes diagnoses was collected from the National Patient Registers, and information on education, emigration and death was collected from the respective national register sources. Individual-level data were linked using unique personal identity codes. The study population included all individuals born alive between 1987 and 2016 to mothers whose country of birth was the respective Nordic country. Individuals were followed until diagnosis of type 1 diabetes, death, emigration or end of follow-up (31 December 2016 in Finland, 31 December 2017 in Norway and Sweden). Gestational age was categorised as extremely preterm (23-27 completed weeks), very preterm (28-31 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), full term (39-41 weeks; reference) and post term (42-45 weeks). HRs and 95% CIs from country-specific covariate-adjusted Cox regression models were combined in a meta-analysis using a common-effect inverse-variance model.

RESULTS

Among 5,501,276 individuals, 0.2% were born extremely preterm, 0.5% very preterm, 0.7% moderately preterm, 4.2% late preterm, 17.7% early term, 69.9% full term, and 6.7% post term. A type 1 diabetes diagnosis was recorded in 12,326 (0.8%), 6364 (0.5%) and 16,856 (0.7%) individuals at a median age of 8.2, 13.0 and 10.5 years in Finland, Norway and Sweden, respectively. Individuals born late preterm or early term had an increased risk of type 1 diabetes compared with their full-term-born peers (pooled, multiple confounder-adjusted HR 1.12, 95% CI 1.07, 1.18; and 1.15, 95% CI 1.11, 1.18, respectively). However, those born extremely preterm or very preterm had a decreased risk of type 1 diabetes (adjusted HR 0.63, 95% CI 0.45, 0.88; and 0.78, 95% CI 0.67, 0.92, respectively). These associations were similar across all three countries.

CONCLUSIONS/INTERPRETATION

Individuals born late preterm and early term have an increased risk of type 1 diabetes while individuals born extremely preterm or very preterm have a decreased risk of type 1 diabetes compared with those born full term.

A multi-ancestry genome-wide association study in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by destruction of the pancreatic β-cells. Genome-wide association (GWAS) and fine mapping studies have been conducted mainly in European ancestry (EUR) populations. We performed a multi-ancestry GWAS to identify SNPs and HLA alleles associated with T1D risk and age at onset. EUR families (N = 3223), and unrelated individuals of African (AFR, N = 891) and admixed (Hispanic/Latino) ancestry (AMR, N = 308) were genotyped using the Illumina HumanCoreExome BeadArray, with imputation to the TOPMed reference panel. The Multi-Ethnic HLA reference panel was utilized to impute HLA alleles and amino acid residues. Logistic mixed models (T1D risk) and frailty models (age at onset) were used for analysis. In GWAS meta-analysis, seven loci were associated with T1D risk at genome-wide significance: PTPN22, HLA-DQA1, IL2RA, RNLS, INS, IKZF4-RPS26-ERBB3, and SH2B3, with four associated with T1D age at onset (PTPN22, HLA-DQB1, INS, and ERBB3). AFR and AMR meta-analysis revealed NRP1 as associated with T1D risk and age at onset, although NRP1 variants were not associated in EUR ancestry. In contrast, the PTPN22 variant was significantly associated with risk only in EUR ancestry. HLA alleles and haplotypes most significantly associated with T1D risk in AFR and AMR ancestry differed from that seen in EUR ancestry; in addition, the HLA-DRB1*08:02-DQA1*04:01-DQB1*04:02 haplotype was 'protective' in AMR while HLA-DRB1*08:01-DQA1*04:01-DQB1*04:02 haplotype was 'risk' in EUR ancestry, differing only at HLA-DRB1*08. These results suggest that much larger sample sizes in non-EUR populations are required to capture novel loci associated with T1D risk.

Lack of association between month of birth and risk of developing type 1 diabetes in Brazil: a 40-year analysis

OBJECTIVES

Seasonal environment at birth may influence diabetes incidence in later life. We sought evidence for this effect and analyzed the association between the month of birth and the risk of developing type 1 diabetes mellitus (T1DM).

METHODS

This was a cohort study carried out with 814 patients diagnosed with T1DM in the region of Bauru - São Paulo State, Brazil, receiving medical care in a private Endocrinology clinic or in the public Brazilian National Health Care System, from 1981 to 2021. All live births that occurred in São Paulo State between 1974 and 2020 were classified by month of birth and were considered as the control group.

RESULTS

We found no statistically significant difference (χ2=16.31, critical 19.68) between the month of birth and risk of developing T1DM, when comparing our patients with the background population of the region. There was no association between the month of birth, sex, age at diagnosis, duration of symptoms before diagnosis, self-reported color, and socioeconomic status.

CONCLUSIONS

We found no association between month of birth and the risk of developing T1DM in this highly admixed South American population. Our data suggest that our population heterogeneity and geographic location may be important factors in the development of T1DM. Future prospective studies, evaluating environmental factors that may confer risk or protection to the disease, are warranted.

Association of residential greenness, air pollution with adverse birth outcomes: Results from 61,762 mother‑neonatal pairs in project ELEFANT (2011-2021)

BACKGROUND

Emerging evidence has demonstrated the benefits of greenness exposure on human health, while conflicts remain unsolved in issue of adverse birth outcomes.

METHODS

Utilizing data from project ELEFANT spanning the years 2011 to 2021, we assessed residential greenness using the NDVI from MODIS data and residential PM2.5 exposure level from CHAP data. Our primary concerns were PTD, LBW, LGA, and SGA. Cox proportional hazard regression model was used to examine the association of residential greenness and air pollution exposure with risk of adverse birth outcomes. We performed mediation and modification effect analyses between greenness and air pollutant.

RESULTS

We identified 61,762 mother‑neonatal pairs in final analysis. For per 10 μg/m3 increase in PM2.5 concentration during entire pregnancy was associated with 19.8 % and 20.7 % increased risk of PTD and LGA. In contrast, we identified that an 0.1 unit increment in NDVI were associated with 24 %, 43 %, 26.5 %, and 39.5 % lower risk for PTD, LBW, LGA, and SGA, respectively. According to mediation analysis, NDVI mediated 7.70 % and 7.89 % of the associations between PM2.5 and PTD and LGA. Residential greenness could reduce the risk of PTD among mothers under 35 years old, living in rural areas, primigravidae and primiparity..

CONCLUSIONS

In summary, our results highlighted the potential of residential greenness to mitigate the risk of adverse birth outcomes, while also pointing to the adverse impact of PM2.5 on increased risk of multiple adverse birth outcomes (PTD and LGA). The significant mediation effect of NDVI emphasizes its potential as an important protective factor of PM2.5 exposure. Additionally, the identification of susceptible subgroups can inform targeted interventions to reduce adverse birth outcomes related to air pollution and lack of green spaces. Further research and understanding of these associations can contribute to better public health strategies aimed at promoting healthier pregnancies and birth outcomes.

Association between the incidence of type 1 diabetes mellitus and tuberculosis or bacillus Calmette-Guérin immunization in children and adolescents

PURPOSE

The correlation between the incidence of type 1 diabetes mellitus (T1DM) and tuberculosis or bacillus Calmette-Guérin (BCG) vaccination rate in individuals aged <15 years was investigated using worldwide data.

METHODS

The incidence of T1DM, rate of BCG vaccination, and incidence of tuberculosis were obtained from the Diabetes Atlas 9th edition of the International Diabetes Federation and the Global Health Observatory data repository of the World Health Organization. Gross domestic product (GDP) per capita and population data by country were obtained from the World Bank and United Nations, respectively.

RESULTS

GDP per capita negatively correlated with the incidence of tuberculosis and positively correlated with the incidence of T1DM (coefficient=-0.630 and 0.596, respectively; all P<0.001). The incidence of T1DM and tuberculosis was significantly associated with the Organisation for Economic Cooperation and Development (OECD) status (P<0.001). After adjusting for GDP per capita, regional grouping, and OECD status, the incidence of T1DM negatively correlated with that of tuberculosis (R2 =0.729, P=0.009). However, there was no association between the BCG vaccination rate and incidence of T1DM (P=0.890).

CONCLUSION

There was a negative correlation between the incidence of tuberculosis and T1DM in children and adolescents aged <15 years at the country level.

Quality of life among schoolchildren with type 1 diabetes mellitus and the satisfaction of their guardians towards school health care in Saudi Arabia

AIMS

This study aimed to assess the quality of life of schoolchildren with type 1 diabetes mellitus (T1DM) and determine their guardians' satisfaction of diabetes health care in Saudi Arabian schools.

METHODS

A cross-section multicenter study was conducted from February to July 2022 among Schoolchildren with T1DM in Saudi Arabia. The study included T1DM school children aged 6-18 years. The patients' health-related quality of life (HRQoL) data were collected and determined using a modified version of the PedsQL 3.0 Diabetes Module.

RESULTS

The grand total median PedQL-DM score among the included participants (N = 283) was 64.7, while items related to diabetes symptoms and diabetes management were 61.1 and 68.7, respectively. Schoolchildren who have lower HbA1c levels and take care of regular monitoring of their blood glucose showed significantly better quality of life concerning diabetes symptoms. A significant number of guardians claimed they were not satisfied with the current status of diabetes management at schools.

CONCLUSIONS

The overall HRQoL among schoolchildren with T1DM was average and acceptable to some extent. The PedsQL-DM median score was higher among those who received health care during school time. The guardians' satisfaction of diabetes health care was low, emphasizing the role of health clinics in schools.

The countdown to type 1 diabetes: when, how and why does the clock start?

'The clock to type 1 diabetes has started when islet antibodies are first detected', commented George Eisenbarth with regard to the pathogenesis of type 1 diabetes. This review focuses on 'starting the clock', i.e. the initiation of pre-symptomatic islet autoimmunity/the first appearance of islet autoantibodies. In particular, this review addresses why susceptibility to developing islet autoimmunity is greatest in the first 2 years of life and why beta cells are a frequent target of the immune system during this fertile period. A concept for the development of beta cell autoimmunity in childhood is discussed and three factors are highlighted that contribute to this early predisposition: (1) high beta cell activity and potential vulnerability to stress; (2) high rates of and first exposures to infection; and (3) a heightened immune response, with a propensity for T helper type 1 (Th1) immunity. Arguments are presented that beta cell injury, accompanied by activation of an inflammatory immune response, precedes the initiation of autoimmunity. Finally, the implications for strategies aimed at primary prevention for a world without type 1 diabetes are discussed.

Maternal depression or anxiety during pregnancy and offspring type 1 diabetes: a population-based family-design cohort study

INTRODUCTION

To investigate the association between maternal depression/anxiety during pregnancy and offspring type 1 diabetes, to assess the specific importance of exposure during pregnancy by comparing across different exposure periods before and/or after pregnancy, and to explore potential unmeasured familial confounding.

RESEARCH DESIGN AND METHODS

This was a population-based cohort including 1 807 809 offspring born in Sweden 2002-2019. From national registers, data were available on diagnosis or medication prescription for depression/anxiety in and around pregnancy, as well as incident cases of type 1 diabetes defined through diagnosis or insulin treatment. Associations were examined using flexible parametric and Cox regression models. Familial confounding was explored using paternal exposure as a negative control and by comparing offspring exposed to maternal depression/anxiety with their unexposed siblings.

RESULTS

For exposure during pregnancy, maternal depression/anxiety was associated with an increased risk of offspring type 1 diabetes onset after, but not before, 8 years of age (adjusted HR (aHR) 1.21 (95% CI 1.03 to 1.42]). Exposure occurring only during pregnancy was similarly associated to type 1 diabetes (aHR 1.24 (0.96 to 1.60)), whereas exposure occurring only before pregnancy was not (aHR 0.91 (0.64 to 1.30)). Associations were close to the null for paternal depression/anxiety (aHR 0.95 (0.72 to 1.25)), and point estimates were above 1 in sibling comparisons, although with wide CIs (aHR 1.36 (0.82 to 2.26)).

CONCLUSIONS

Maternal depression/anxiety specifically during pregnancy seems to be associated with offspring type 1 diabetes. Paternal negative control and sibling comparisons indicate that the results cannot entirely be explained by familial confounding.

Changes in the Global Epidemiology of Type 1 Diabetes in an Evolving Landscape of Environmental Factors: Causes, Challenges, and Opportunities

The worldwide incidence of type 1 diabetes mellitus (T1DM) has increased in recent decades. The reasons behind this phenomenon are not yet fully understood. Early life infections, prenatal and perinatal factors, and diet composition have been associated with the triggering of autoimmunity and the risk of presentation of T1DM. However, the rapid increase in new cases of the disease raises the hypothesis that lifestyle factors, which have traditionally been associated with type 2 diabetes, such as obesity and unhealthy eating patterns could also play a role in the genesis of autoimmune diabetes. This article aims to highlight the changing epidemiology of T1DM and the importance of properly recognizing the environmental factors behind it, as well as the connections with the pathogenesis of the disorder and the need to prevent or delay T1DM and its long-term complications.

National and sub-national burden and trend of type 1 diabetes in 31 provinces of Iran, 1990-2019

The aim of the study was to report the burden of type one diabetes mellitus (T1DM) by sex, age, year, and province in Iran over the past 30 years, according to data provided by the global burden of disease (GBD) study. Incidence, prevalence, death, disability-adjusted life-years (DALYs), years of life lost, and years lived with disability due to T1DM by age groups and sex was reported for 31 provinces of Iran from 1990 to 2019 with their 95% uncertainty intervals (UI). In 2019, national age-standardized incidence (11.0 (95% UI: 8.9-13.5)), prevalence (388.9 (306.1-482.1)), death (0.7 (0.6-0.8)), and DALYs (51.7 (40.9-65.1)) rates per 100,000 wre higher than 1990 except for death. Also, the mortality to incidence ratio reduced in all provinces over time particularly after 2014 as well. GBD data analysis showed that age-standardized incidence and prevalence rates of T1DM have increased, the death rate reduced, and DALYs remained unchanged during the past 30 years in Iran and its 31 provinces. death rate reduced and DALYs remained unchanged during the past 30 years in Iran and its 31 provinces.

Predicting the development of T1D and identifying its Key Performance Indicators in children; a case-control study in Saudi Arabia

The increasing incidence of type 1 diabetes (T1D) in children is a growing global concern. It is known that genetic and environmental factors contribute to childhood T1D. An optimal model to predict the development of T1D in children using Key Performance Indicators (KPIs) would aid medical practitioners in developing intervention plans. This paper for the first time has built a model to predict the risk of developing T1D and identify its significant KPIs in children aged (0-14) in Saudi Arabia. Machine learning methods, namely Logistic Regression, Random Forest, Support Vector Machine, Naive Bayes, and Artificial Neural Network have been utilised and compared for their relative performance. Analyses were performed in a population-based case-control study from three Saudi Arabian regions. The dataset (n = 1,142) contained demographic and socioeconomic status, genetic and disease history, nutrition history, obstetric history, and maternal characteristics. The comparison between case and control groups showed that most children (cases = 68% and controls = 88%) are from urban areas, 69% (cases) and 66% (control) were delivered after a full-term pregnancy and 31% of cases group were delivered by caesarean, which was higher than the controls (χ2 = 4.12, P-value = 0.042). Models were built using all available environmental and family history factors. The efficacy of models was evaluated using Area Under the Curve, Sensitivity, F Score and Precision. Full logistic regression outperformed other models with Accuracy = 0.77, Sensitivity, F Score and Precision of 0.70, and AUC = 0.83. The most significant KPIs were early exposure to cow's milk (OR = 2.92, P = 0.000), birth weight >4 Kg (OR = 3.11, P = 0.007), residency(rural) (OR = 3.74, P = 0.000), family history (first and second degree), and maternal age >25 years. The results presented here can assist healthcare providers in collecting and monitoring influential KPIs and developing intervention strategies to reduce the childhood T1D incidence rate in Saudi Arabia.

Cardiovascular outcomes in type 1 and type 2 diabetes

Diabetes is one of the most prevalent cardiometabolic disorders on the planet. Type 1 diabetes accounts for only a minority of all cases (recently estimated to be ~2% globally); however, since this is a disorder with an early onset, many people live with type 1 diabetes for a long time. CVD and premature death are the main long-term outcomes for both types of diabetes; however, the type of diabetes that carries the highest risk of these outcomes is a controversial topic and has not been widely studied. Because of the association between diabetes and CVD, the rise in type 2 diabetes prevalence over the past decades has huge effects on global health. The excess risk in people with diabetes compared with those without depends, to a large extent, on the presence of other factors, such as general cardiovascular risk factors (e.g. elevated LDL-cholesterol, hypertension and smoking) and also factors that are more specific to diabetes (e.g. HbA1c, and micro- and macroalbuminuria). Some contributory factors are modifiable, while others are not, such as age, sex and type of diabetes. Older people with type 2 diabetes who have risk factors that are under control can achieve levels of CVD risk that are similar to that of the general population, while younger individuals with type 1 diabetes are mostly unable to achieve similar levels of risk, probably because of long and cumulative exposure to raised blood glucose levels. Despite reports of declining rates of CVD among people with type 1 and type 2 diabetes, rising rates of both types of diabetes lead to a continuing rise in the number of people with cardiometabolic disorders worldwide, offsetting the progress made in many countries. Comparison between individuals with type 1 and type 2 diabetes with respect to risk of CVD is fraught with difficulties and highly dependent on other, concomitant factors, some of which are modifiable and others not. Nonetheless, as a whole, what matters most in determining the management of diabetes is absolute risk and lifetime risk. Life-long efforts to achieve glycaemic control, control of lipids and hypertension, and not smoking are key to prevention, with a healthy lifestyle and pharmacological therapy to be implemented as needed.

Maternal hypertensive disorders during pregnancy and the risk of offspring diabetes mellitus in childhood, adolescence, and early adulthood: a nationwide population-based cohort study

BACKGROUND

Maternal hypertensive disorders during pregnancy (HDP) have been suggested to contribute to the development of offspring cardiovascular disease later in life, but empirical evidence remains inconsistent. This study was aimed to assess the association of maternal overall and type-specific HDPs with diabetes in offspring from childhood to early adulthood.

METHODS

Using Danish national health registers, a total of 2,448,753 individuals born in Denmark from 1978 to 2018 were included in this study. Maternal HDP included chronic hypertension, gestational hypertension, and preeclampsia. The outcome of interest was diabetes in offspring (including type 1, type 2, and gestational diabetes). The follow-up of offspring started at birth and ended at the first diagnosis of diabetes, emigration from Denmark, death, or time end on 31 December 2018, whichever came first. Cox proportional hazards regression was used to evaluate the hazard ratios (HRs) with 95% confidence intervals (CIs) of the association between maternal HDP and diabetes (including type 1, type 2, and gestational diabetes) in offspring from birth to young adulthood (up to 41 years), with the offspring's age as the time scale.

RESULTS

During a follow-up of up to 41 (median: 19.3) years, 1247 offspring born to mothers with HDP and 23,645 offspring born to mothers without HDP were diagnosed with diabetes. Compared with offspring born to mothers without HDP, those born to mothers with HDP had an increased risk for overall diabetes (HR=1.27, 95% CI=1.20-1.34), as well as for type 2 diabetes (HR=1.57, 95% CI=1.38-1.78) and gestational diabetes (HR=1.37, 95% CI=1.25-1.49). We did not observe obvious increased risk for type 1 diabetes (HR=1.08, 95% CI=0.98-1.18). Offspring of mothers with gestational hypertension (HR=1.37, 95% CI=1.00-1.88) or preeclampsia (HR=1.62, 95% CI=1.41-1.87) had higher risks of type 2 diabetes. The strongest association was observed for severe preeclampsia, with a 2-fold risk of type 2 diabetes (HR=2.00, 95% CI=1.42-2.82). The association between maternal HDP and type 1 diabetes did not reach statistical significance, except for maternal gestational hypertension (HR=1.41, 95%CI=1.17-1.71). In addition, we found that offspring born to mothers with any subtypes of maternal HDP had higher risk of gestational diabetes, and the corresponding HRs (95%CIs) for chronic hypertension, gestational hypertension, and preeclampsia were 1.60 (1.06-2.41), 1.29 (1.04-1.59), and 1.38 (1.24-1.53), respectively. We also observed stronger associations among offspring of mothers with HDP and comorbid diabetes (HR=4.64, 95%CI=3.85-5.60) than offspring of mothers with HDP or diabetes alone.

CONCLUSIONS

Offspring of mothers with HDP, especially mothers with comorbid diabetes, had an increased risk of diabetes later in their life. Our findings suggest that timely and effective prevention of HDP in women of childbearing age should be taken into consideration as diabetes prevention and control strategies for their generations.

The incidence of childhood-onset type 1 diabetes, time trends and association with the population composition in Sweden: a 40 year follow-up

AIMS/HYPOTHESIS

During the 1980s and 1990s, the incidence of childhood-onset type 1 diabetes more than doubled in Sweden, followed by a plateau. In the present 40 year follow-up, we investigated if the incidence remained stable and whether this could be explained by increased migration from countries reporting lower incidences.

METHODS

We used 23,143 incident cases of childhood-onset type 1 diabetes reported between 1978 and 2019 to the nationwide, population-based Swedish Childhood Diabetes Registry and population data from Statistics Sweden. Generalised additive models and ANOVA were applied to analyse the effects of onset age, sex, time trends and parental country of birth and interaction effects between these factors.

RESULTS

The flattening of the incidence increase seems to remain over the period 2005-2019. When comparing the incidence of type 1 diabetes for all children in Sweden with that for children with both parents born in Sweden, the trends were parallel but at a higher level for the latter. A comparison of the incidence trends between individuals with Swedish backgrounds (high diabetes trait) and Asian backgrounds (low diabetes trait) showed that the Asian subpopulation had a stable increase in incidence over time.

CONCLUSIONS/INTERPRETATION

In Sweden, the increase in incidence of childhood-onset type 1 diabetes in the late 20th century has been approaching a more stable albeit high level over the last two decades. Increased immigration from countries with lower incidences of childhood-onset type 1 diabetes does not provide a complete explanation for the observed levelling off.

Trends in incidence rates of childhood type 1 diabetes mellitus: A retrospective study in Isfahan province, Iran

AIMS/INTRODUCTION

We aimed to determine the incidence trend of childhood type 1 diabetes mellitus in Isfahan province over a period of 12 years.

MATERIALS AND METHODS

In this retrospective study, children aged <20 years at the time of type 1 diabetes mellitus diagnosis, from March 2007 to March 2019, were included. The crude and adjusted incidence rate of type 1 diabetes mellitus is calculated as the number of cases per 100,000 person-years by the period. The cumulative, age- and sex-specific incidence rates were also calculated. Age-specific incidence rates were calculated for age and sex groups.

RESULTS

A total of 1,954 (983 boys and 971 girls) cases of type 1 diabetes mellitus were identified. The mean age at diagnosis in all studied populations was 9.89 (standard deviation 4.76). There were no significant differences between the proportion of boys and girls in different years (P = 0.12) and different age groups (P = 0.19). The average annual percent change of incidence rate for the total population, for girls and boys, was 6.9%, 6.7% and 6.3% respectively. The type 1 diabetes mellitus incidence rate had a significant trend to be increased from 2007 to 2019 (P < 0.001, t = 3.6).

CONCLUSION

Our findings showed that currently our region is considered a region with a high incidence rate of type 1 diabetes mellitus. Although we have had fluctuations in the incidence rate over the 12 years, the overall trend is increasing.

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.

Obesity in late adolescence and incident type 1 diabetes in young adulthood

AIMS/HYPOTHESIS

Studies in children have reported an association between increased BMI and risk for developing type 1 diabetes, but evidence in late adolescence is limited. We studied the association between BMI in late adolescence and incident type 1 diabetes in young adulthood.

METHODS

All Israeli adolescents, ages 16-19 years, undergoing medical evaluation in preparation for mandatory military conscription between January 1996 and December 2016 were included for analysis unless they had a history of dysglycaemia. Data were linked with information about adult onset of type 1 diabetes in the Israeli National Diabetes Registry. Weight and height were measured at study entry. Cox proportional models were applied, with BMI being analysed both as a categorical and as a continuous variable.

RESULTS

There were 777 incident cases of type 1 diabetes during 15,819,750 person-years (mean age at diagnosis 25.2±3.9 years). BMI was associated with incident type 1 diabetes. In a multivariable model adjusted for age, sex and sociodemographic variables, the HRs for type 1 diabetes were 1.05 (95% CI 0.87, 1.27) for the 50th-74th BMI percentiles, 1.41 (95% CI 1.11, 1.78) for the 75th-84th BMI percentiles, 1.54 (95% CI 1.23, 1.94) for adolescents who were overweight (85th-94th percentiles), and 2.05 (95% CI 1.58, 2.66) for adolescents with obesity (≥95th percentile) (reference group: 5th-49th BMI percentiles). One increment in BMI SD was associated with a 25% greater risk for incidence of type 1 diabetes (HR 1.25, 95% CI 1.17, 1.32).

CONCLUSIONS

Excessively high BMI in otherwise healthy adolescents is associated with increased risk for incident type 1 diabetes in early adulthood.

Maternal diabetes negatively impacts fetal health

Diabetes is a chronic metabolic disease affecting an increasing number of people. Although diabetes has negative health outcomes for diagnosed individuals, a population at particular risk are pregnant women, as diabetes impacts not only a pregnant woman's health but that of her child. In this review, we cover the current knowledge and unanswered questions on diabetes affecting an expectant mother, focusing on maternal and fetal outcomes.

Age at diagnosis, anthropometry and birthweight in two ethnically different cohorts of children with type 1 diabetes living in Northwest England or Singapore

AIM

To compare children with type 1 diabetes (T1D) living in the Northwest England, United Kingdom (UK) or Singapore, and to correlate age at diagnosis with birthweight and anthropometry at T1D diagnosis.

METHODS

We included 166 T1D children of white ethnicity in England (UK-White) and 185 T1D children of East-Asian ethnicity origin in Singapore (SG-Asian) who were born between 2002 and 2020.

RESULTS

The cohorts from UK-White and SG-Asian children differed significantly in FH of T1D (p < 0.001), FH of T2D (p < 0.001) and pubertal status at diagnosis (p = 0.01). Median interquartile range (IQR) for age at diagnosis was similar in the two groups. UK-White children had significantly higher birthweight SDS, height SDS, weight SDS and BMI SDS (all p < 0.001). Among the subgroup of 174 children who were prepubertal and diagnosed after age 5 years, the UK-White children were 11 months older than the SG-Asian children (p = 0.02) indicating that SG-Asian children at the time of T1D diagnosis were more likely to be in puberty compared with UK-White children (30% vs. 18%).

CONCLUSION

These two cohorts have substantially different genetic and environmental backgrounds, yet age at the diagnosis of T1D was similar except for the prepubertal children who were diagnosed after 5 years old. Timing of puberty and other factors may influence how early T1D presents during childhood.

The association between late preterm birth and cardiometabolic conditions across the life course: A systematic review and meta-analysis

BACKGROUND

The effect of being born late preterm (34-36 weeks gestation) on cardiometabolic outcomes across the life course is unclear.

OBJECTIVES

To systematically review the association between being born late preterm (spontaneous or indicated), compared to the term and cardiometabolic outcomes in children and adults.

DATA SOURCES

EMBASE(Ovid), MEDLINE(Ovid), CINAHL.

STUDY SELECTION AND DATA EXTRACTION

Observational studies up to July 2021 were included. Study characteristics, gestational age, cardiometabolic outcomes, risk ratios (RRs), odds ratios (ORs), hazard ratios (HRs), mean differences and 95% confidence intervals (CIs) were extracted.

SYNTHESIS

We pooled converted RRs using random-effects meta-analyses for diabetes, hypertension, ischemic heart disease (IHD) and body mass index (BMI) with subgroups for children and adults. The risk of bias was assessed using the Newcastle-Ottawa scale and certainty of the evidence was assessed using the grading of recommendations, assessment, development and evaluation (GRADE) approach.

RESULTS

Forty-one studies were included (41,203,468 total participants; median: 5.0% late preterm). Late preterm birth was associated with increased diabetes (RR 1.24, 95% CI 1.17, 1.32; nine studies; n = 6,056,511; incidence 0.9%; I² 51%; low certainty) and hypertension (RR 1.21, 95% CI 1.13, 1.30; 11 studies; n = 3,983,141; incidence 3.4%; I² 64%; low certainty) in children and adults combined. Late preterm birth was associated with decreased BMI z-scores in children (standard mean difference -0.38; 95% CI -0.67, -0.09; five studies; n = 32,602; proportion late preterm 8.3%; I² 96%; very low certainty). There was insufficient evidence that late preterm birth was associated with increased IHD risk in adults (HR 1.20, 95% CI 0.89, 1.62; four studies; n = 2,706,806; incidence 0.3%; I² 87%; very low certainty).

CONCLUSIONS

Late preterm birth was associated with an increased risk of diabetes and hypertension. The certainty of the evidence was low or very low. Inconsistencies in late preterm and term definitions, confounding variables and outcome age limited the comparability of studies.

Environmental Triggering of Type 1 Diabetes Autoimmunity

Type 1 diabetes (T1D) is a chronic autoimmune disease in which pancreatic islet β cells are destroyed by immune cells, ultimately leading to overt diabetes. The progressive increase in T1D incidence over the years points to the role of environmental factors in triggering or accelerating the disease process which develops on a highly multigenic susceptibility background. Evidence that environmental factors induce T1D has mostly been obtained in animal models. In the human, associations between viruses, dietary habits or changes in the microbiota and the development of islet cell autoantibodies or overt diabetes have been reported. So far, prediction of T1D development is mostly based on autoantibody detection. Future work should focus on identifying a causality between the different environmental risk factors and T1D development to improve prediction scores. This should allow developing preventive strategies to limit the T1D burden in the future.

Prenatal Betamethasone Exposure and its Impact on Pediatric Type 1 Diabetes Mellitus: A Preliminary Study in a Spanish Cohort

BACKGROUND

Betamethasone, a glucocorticoid used to induce lung maturation when there is a risk of preterm delivery, can affect the immune system maturation and type 1 diabetes (T1D) incidence in the progeny. It has been described that prenatal betamethasone protects offspring from experimental T1D development. The main aim of this study was to evaluate the possible association between betamethasone prenatal exposure and T1D in humans. Research Design and Methods. A retrospective case-control study with a total of 945 children, including 471 patients with T1D and 474 healthy siblings, was performed. Participants were volunteers from the Germans Trias i Pujol Hospital and DiabetesCero Foundation. Parents of children enrolled in the study completed a questionnaire that included questions about weeks of gestation, preterm delivery risk, weight at birth, and prenatal betamethasone exposure of their children. Multiple logistic regression was used to detect the association between betamethasone exposure and T1D.

RESULTS

We compared T1D prevalence between subjects prenatally exposed or unexposed to betamethasone. The percent of children with T1D in the exposed group was 37.5% (21 of 56), and in the unexposed group was 49.52% (410 of 828) (p = 0.139). The percentage of betamethasone-treated subjects with T1D in the preterm group (18.05%, 13 of 72) was significantly higher than that found in the control group (12.5%, 9 of 72) (p = 0.003). The odds ratio for T1D associated with betamethasone in the univariate logistic regression was 0.59 (95% confidence interval, 0.33; 1.03 [p = 0.062]) and in the multivariate logistic regression was 0.83 (95% confidence interval, 0.45; 1.52 [p = 0.389]).

CONCLUSIONS

The results demonstrate that the prenatal exposure to betamethasone does not increase T1D susceptibility, and may even be associated with a trend towards decreased risk of developing the disease. These preliminary findings require further prospective studies with clinical data to confirm betamethasone exposure effect on T1D risk.

Cesarean delivery and risk of hospitalization for autoimmune disorders before 14 years of age

It is supposed that cesarean birth is implicated in the development of autoimmunity. We evaluated the association between cesarean delivery and the risk of hospitalization for autoimmune disease in children up to 14 years of age. We performed a longitudinal cohort study of 934,873 children born between 2006 and 2019 in Quebec, Canada. The main exposure measure was cesarean delivery versus vaginal delivery (spontaneous or induced). Outcomes included hospitalization for type 1 diabetes, celiac disease, or other autoimmune disorders before 14 years of age. We used Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between cesarean delivery and hospitalization for autoimmune disorders, adjusted for patient characteristics. A total of 248,963 children (27%) were delivered by cesarean. Median length of follow-up was 7.4 years. The hospitalization rate for autoimmune disorders was 69.1 per 100,000 person-years for cesarean and 65.9 per 100,000 person-years for vaginal delivery. Cesarean delivery was not associated with autoimmune disorders overall (HR 1.02, 95% CI 0.96-1.10). There was no association with type 1 diabetes (HR 1.00, 95% CI 0.85-1.17), celiac disease (HR 0.86, 95% CI 0.71-1.04), inflammatory bowel disease (HR 1.15, 95% CI 0.88-1.49), or idiopathic thrombocytopenic purpura (HR 1.01, 95% CI 0.82-1.25). Cesarean delivery was not associated with autoimmune disorders at different ages.Conclusion: This study suggests that cesarean delivery is not associated with the risk of hospitalization for autoimmune disorders before 14 years of age. Delivery mode does not seem to mediate the risk of autoimmunity in childhood. What is Known: • Children born by cesarean may be at risk of abnormal immune development. • The association between cesarean delivery and risk of pediatric autoimmune disorders is unclear. What is New: • In this cohort study of over 900,000 children, cesarean delivery was not associated with the risk of hospitalization for a range of autoimmune disorders before 14 years of age. • Cesarean delivery may not be related to the development of autoimmunity.

Maternal prepregnancy BMI and physical activity and type 1 diabetes in the offspring

BACKGROUND

Previous studies showed conflicting results on the association between maternal prepregnancy body mass index (BMI) and type 1 diabetes in the offspring, and the role of maternal prepregnancy physical activity is unclear. We aimed to assess whether maternal prepregnancy BMI and physical activity predict type 1 diabetes in their offspring.

METHODS

Prospective study including women participating in the Nurses' Health Study II with follow-up from 1989 to 2011. Women repeatedly reported their BMI and physical activity, from which prepregnancy exposures were derived; and retrospectively reported their BMI at age 18 and physical activity at ages 18-22, considered early adulthood exposure. We estimated risk ratios (RR) and 95% confidence intervals (95%CI) using generalized estimating equations, adjusted for covariates. Findings at p < 0.05 were considered statistically significant.

RESULTS

We identified 276 cases of type 1 diabetes among offspring (n = 70,168) with maternal prepregnancy information and 448 cases among offspring (n = 111,692) with maternal early adulthood information. Prepregnancy and early adulthood maternal BMI and physical activity were not associated with offspring type 1 diabetes. The RR comparing overweight to normal weight mothers was 1.08 (95%CI: 0.73-1.59) and comparing obese to normal weight was 0.94 (95%CI: 0.49-1.79, p-trend: 0.98). Comparing highest to lowest quartile of maternal physical activity the RR was 0.90 (95%CI: 0.61-1.32; p-trend: 0.73). Maternal type 2 diabetes was associated with an increased risk of type 1 diabetes in the offspring (RR = 1.87; 95%CI: 1.25-2.80).

CONCLUSIONS

Our findings do not support a relationship between maternal prepregnancy BMI or physical activity and the risk of type 1 diabetes in the offspring.

Prediction of Type 1 Diabetes at Birth: Cord Blood Metabolites vs Genetic Risk Score in the Norwegian Mother, Father, and Child Cohort

BACKGROUND AND AIM

Genetic markers are established as predictive of type 1 diabetes, but unknown early life environment is believed to be involved. Umbilical cord blood may reflect perinatal metabolism and exposures. We studied whether selected polar metabolites in cord blood contribute to prediction of type 1 diabetes.

METHODS

Using a targeted UHPLC-QQQ-MS platform, we quantified 27 low-molecular-weight metabolites (including amino acids, small organic acids, and bile acids) in 166 children, who later developed type 1 diabetes, and 177 random control children in the Norwegian Mother, Father, and Child cohort. We analyzed the data using logistic regression (estimating odds ratios per SD [adjusted odds ratio (aOR)]), area under the receiver operating characteristic curve (AUC), and k-means clustering. Metabolites were compared to a genetic risk score based on 51 established non-HLA single-nucleotide polymorphisms, and a 4-category HLA risk group.

RESULTS

The strongest associations for metabolites were aminoadipic acid (aOR = 1.23; 95% CI, 0.97-1.55), indoxyl sulfate (aOR = 1.15; 95% CI, 0.87-1.51), and tryptophan (aOR = 0.84; 95% CI, 0.65-1.10), with other aORs close to 1.0, and none significantly associated with type 1 diabetes. K-means clustering identified 6 clusters, none of which were associated with type 1 diabetes. Cross-validated AUC showed no predictive value of metabolites (AUC 0.49), whereas the non-HLA genetic risk score AUC was 0.56 and the HLA risk group AUC was 0.78.

CONCLUSIONS

In this large study, we found no support of a predictive role of cord blood concentrations of selected bile acids and other small polar metabolites in the development of type 1 diabetes.

Size for gestational age affects the risk for type 1 diabetes in children and adolescents: a Swedish national case-control study

AIM/HYPOTHESIS

Environmental factors are believed to contribute to the risk of developing type 1 diabetes. The aim of this study was to investigate how size for gestational age affects the risk of developing childhood type 1 diabetes.

METHODS

Using the Swedish paediatric diabetes quality register and the Swedish medical birth register, children with type 1 diabetes diagnosed between 2000 and 2012 (n = 9376) were matched with four control children (n = 37,504). Small for gestational age (SGA) and large for gestational age (LGA) were defined according to Swedish national standards. Data were initially analysed using Pearson's χ² and thereafter by single and multiple logistic regression models.

RESULTS

An equal proportion of children were born appropriate for gestational age, but children with type 1 diabetes were more often born LGA and less often born SGA than control children (4.7% vs 3.5% and 2.0% vs 2.6%, respectively, p < 0.001). In the multiple logistic regression analysis, being born LGA increased (adjusted OR 1.16 [95% CI 1.02, 1.32]) and SGA decreased (adjusted OR 0.76 [95% CI 0.63, 0.92]) the risk for type 1 diabetes, regardless of maternal BMI and diabetes.

CONCLUSIONS/INTERPRETATION

Size for gestational age of Swedish children affects the risk of type 1 diabetes, with increased risk if the child is born LGA and decreased risk if the child is born SGA. Being born LGA is an independent risk factor for type 1 diabetes irrespective of maternal BMI and diabetes. Thus, reducing the risk for a child being born LGA might to some extent reduce the risk for type 1 diabetes.

The Association Between High Birth Weight and Long-Term Outcomes-Implications for Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

Background: Studies have shown that the prevalence of children born with high birth weight or large for gestational age (LGA) is increasing. This is true for spontaneous pregnancies; however, children born after frozen embryo transfer (FET) as part of assisted reproductive technology (ART) also have an elevated risk. In recent years, the practice of FET has increased rapidly and while the perinatal and obstetric risks are well-studied, less is known about the long-term health consequences. Objective: The aim of this systematic review was to describe the association between high birth weight and LGA on long-term child outcomes. Data Sources: PubMed, Scopus, and Web of Science were searched up to January 2021. Exposure included high birth weight and LGA. Long-term outcome variables included malignancies, psychiatric disorders, cardiovascular disease, and diabetes. Study Selection: Original studies published in English or Scandinavian languages were included. Studies with a control group were included while studies published as abstracts and case reports were excluded. Data Extraction: The methodological quality, in terms of risk of bias, was assessed by pairs of reviewers. Robins-I (www.methods.cochrane.org) was used for risk of bias assessment in original articles. For systematic reviews, AMSTAR (www.amstar.ca) was used. For certainty of evidence, we used the GRADE system. The systematic review followed PRISMA guidelines. When possible, meta-analyses were performed. Results: The search included 11,767 articles out of which 173 met the inclusion criteria and were included in the qualitative analysis, while 63 were included in quantitative synthesis (meta-analyses). High birth weight and/or LGA was associated with low to moderately elevated risks for certain malignancies in childhood, breast cancer, several psychiatric disorders, hypertension in childhood, and type 1 and 2 diabetes. Conclusions: Although the increased risks for adverse outcome in offspring associated with high birth weight and LGA represent serious health effects in childhood and in adulthood, the size of these effects seems moderate. The identified risk association should, however, be taken into account in decisions concerning fresh and frozen ART cycles and is of general importance in view of the increasing prevalence in high birthweight babies.

Perinatal risk factors for pediatric onset type 1 diabetes, autoimmune thyroiditis, juvenile idiopathic arthritis, and inflammatory bowel diseases

Type 1 diabetes mellitus (DM), autoimmune thyroiditis (AIT), juvenile idiopathic arthritis (JIA), and inflammatory bowel diseases (IBD) are common pediatric autoimmune diseases with unknown risk factors. Using nationwide registers, we searched for their perinatal risk factors. Our study followed up 11,407 children (born 2000-2005) for a median of 16.6 years (from birth to 2018). Of them, 2.15% received primary diagnosis and 0.08% also secondary: 0.89% had DM, 0.60% had AIT, 0.48% had JIA, and 0.25% had IBD. The incidences per 100,000 children/year were 106.1 for DM, 46.0 for AIT, 55.0 for JIA, and 23.7 for IBD. There were more preterm births (< 37 weeks) among children with studied autoimmune diseases compared with the rest of the cohort (8.6% vs. 5.3%, p = 0.035). Among those born preterm, children with studied autoimmune diseases received more postnatal antibiotics compared with other preterm children in the cohort (47.6% vs. 27.7%, p = 0.046). Children with IBD were born to older mothers compared with those without studied diagnoses (33.0 vs 30.2, p = 0.004).Conclusion: Preterm birth was a shared risk factor for autoimmune diseases in our study, especially when combined with postnatal antibiotic treatments. High maternal age was associated with IBD. What is Known: • Type 1 diabetes (DM), autoimmune thyroiditis (AIT), juvenile idiopathic arthritis (JIA), and inflammatory bowel diseases (IBD) are common pediatric autoimmune diseases • It is unclear whether these diseases have shared risk factors, since there are no previous simultaneous epidemiological nor follow-up studies on them in one cohort  What is New: • Preterm births were more common in children with DM, AIT, JIA, or IBD compared with other children in the cohort, and preterm children who developed these diseases recieved more postnatal antibiotics compared with other preterm children • High maternal age was associated with IBD.

Preterm Birth and Birth Weight and the Risk of Type 1 Diabetes in Chinese Children

AIMS

Findings from previous studies about the association of preterm birth as well as birth weight with the risk of T1DM were still inconsistent. We aimed to further clarify these associations based on Chinese children and explore the role of gender therein.

METHODS

A nationwide multicenter and population-based large cross-sectional study was conducted in China from 2017 to 2019. Children aged between 3 and 18 years old with complete information were included in this analysis. Multiple Poisson regression models were used for evaluating the associations of birth weight as well as preterm birth with T1DM in children.

RESULTS

Out of 181,786 children, 82 childhood T1DM cases were identified from questionnaire survey. Children with preterm birth (<37 weeks) had higher risk of type 1 diabetes (OR: 3.17, 95%CI: 1.76-5.71). Children born with high birth weight (≥4,000g) had no statistically significant risk of T1DM (OR:1.71, 95%CI: 0.90-3.22). However, children's gender might modify the effect of high birth weight on T1DM (girls: OR: 3.15, 95%CI: 1.33-7.47; boys: OR: 0.99, 95%CI: 0.38-2.55, p for interaction=0.065). In addition, children with low birth weight were not associated with T1DM (OR: 0.70, 95%CI: 0.24-2.08). The findings from matched data had the similar trend.

CONCLUSIONS

In China mainland, preterm birth increased the risk of childhood T1DM, but high birth weight only affected girls. Therefore, early prevention of T1DM may start with prenatal care to avoid adverse birth outcomes and more attention should be paid to children with preterm birth and girls with high birth weight after birth.

Why is the Incidence of Type 1 Diabetes Increasing?

Type 1 diabetes is a condition that can lead to serious long-term complications and can have significant psychological and quality of life implications. Its incidence is increasing in all parts of the world, but the reasons for this are incompletely understood. Genetic factors alone cannot explain such a rapid increase in incidence; therefore, environmental factors must be implicated. Lifestyle factors have been classically associated with type 2 diabetes. However, there are data implicating obesity and insulin resistance to type 1 diabetes as well (accelerator hypothesis). Cholesterol has also been shown to be correlated with the incidence of type 1 diabetes; this may be mediated by immunomodulatory effects of cholesterol. There is considerable interest in early life factors, including maternal diet, mode of delivery, infant feeding, childhood diet, microbial exposure (hygiene hypothesis), and use of anti-microbials in early childhood. Distance from the sea has recently been shown to be negatively correlated with the incidence of type 1 diabetes. This may contribute to the increasing incidence of type 1 diabetes since people are increasingly living closer to the sea. Postulated mediating mechanisms include hours of sunshine (and possibly vitamin D levels), mean temperature, dietary habits, and pollution. Ozone, polychlorinated biphenyls, phthalates, trichloroethylene, dioxin, heavy metals, bisphenol, nitrates/nitrites, and mercury are amongst the chemicals which may increase the risk of type 1 diabetes. Another area of research concerns the role of the skin and gut microbiome. The microbiome is affected by many of the factors mentioned above, including the mode of delivery, infant feeding, exposure to microbes, antibiotic use, and dietary habits. Research on the reasons why the incidence of type 1 diabetes is increasing not only sheds light on its pathogenesis but also offers insights into ways we can prevent type 1 diabetes.

Maternal bacteria to correct abnormal gut microbiota in babies born by C-section

INTRODUCTION

There is evidence that caesarean section (CS) is associated with increased risk of childhood obesity, asthma, and coeliac disease. The gut microbiota of CS-born babies differs to those born vaginally, possibly due to reduced exposure to maternal vaginal bacteria during birth. Vaginal seeding is a currently unproven practice intended to reduce such differences, so that the gut microbiota of CS-born babies is similar to that of babies born vaginally. Our pilot study, which uses oral administration as a novel form of vaginal seeding, will assess the degree of maternal strain transfer and overall efficacy of the procedure for establishing normal gut microbiota development.

METHODS AND ANALYSIS

Protocol for a single-blinded, randomized, placebo-controlled pilot study of a previously untested method of vaginal seeding (oral administration) in 30 CS-born babies. A sample of maternal vaginal bacteria is obtained prior to CS, and mixed with 5 ml sterile water to obtain a supernatant. Healthy babies are randomized at 1:1 to receive active treatment (3 ml supernatant) or placebo (3 ml sterile water). A reference group of 15 non-randomized vaginal-born babies are also being recruited. Babies' stool samples will undergo whole metagenomic shotgun sequencing to identify potential differences in community structure between CS babies receiving active treatment compared to those receiving placebo at age 1 month (primary outcome). Secondary outcomes include differences in overall gut community between CS groups (24 hours, 3 months); similarity of CS-seeded and placebo gut profiles to vaginally-born babies (24 hours, 1 and 3 months); degree of maternal vaginal strain transfer in CS-born babies (24 hours, 1 and 3 months); anthropometry (1 and 3 months) and body composition (3 months).

ETHICS AND DISSEMINATION

Ethics approval by the Northern A Health and Disability Ethics Committee (18/NTA/49). Results will be published in peer-reviewed journals and presented at international conferences.

REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12618000339257).

Perinatal factors and the risk of type 1 diabetes in childhood and adolescence-A register-based case-cohort study in Finland, years 1987 to 2009

OBJECTIVES

Our aim was to clarify previously reported associations and to explore new ones between various maternal background and perinatal factors and the risk of type 1 diabetes in childhood.

METHODS

We identified all children born 1 January 1987 to 31 December 2008 in Finland and diagnosed with type 1 diabetes by age 16 years or end of 2009 from the Special Reimbursement Register (n = 6862). A 10% random sample from each birth year cohort was selected as a reference cohort (n = 127 216). Information on perinatal factors was obtained from the Finnish Medical Birth Register.

RESULTS

Maternal diabetes (hazard ratios [HR] = 6.43; 95% confidence interval [CI] 5.35, 7.73), maternal asthma (HR = 1.23; 95% CI 1.06, 1.43), child's high birth length for gestational age (HR = 1.35; 95% CI 1.22, 1.51 highest vs lowest quintile) and premature or early term birth (HR = 1.21; 95% CI 1.05, 1.39 gestational weeks 33-36 and HR = 1.17; 95% CI 1.09, 1.26 gestational weeks 37-38 vs gestational weeks 39-40) was associated with an increased risk of type 1 diabetes when adjusted for several potential confounders. Maternal smoking during pregnancy (HR = 0.72; 95% CI 0.66, 0.77), high number of previous live births (HR = 0.65; 95% CI 0.55, 0.76 ≥ 4 vs 0 live births), and the child being born small for gestational age (HR = 0.80; 95% CI 0.67, 0.96) was associated with a decreased risk of type 1 diabetes.

CONCLUSIONS

Findings on maternal asthma and high birth length for gestational age increasing the risk of type 1 diabetes are novel and need to be confirmed. Our findings indicate that perinatal factors may play a role in the development of type 1 diabetes.

Early Childhood Antibiotic Treatment for Otitis Media and Other Respiratory Tract Infections Is Associated With Risk of Type 1 Diabetes: A Nationwide Register-Based Study With Sibling Analysis

OBJECTIVE

The effect of early-life antibiotic treatment on the risk of type 1 diabetes is debated. This study assessed this question, applying a register-based design in children up to age 10 years including a large sibling-control analysis.

RESEARCH DESIGN AND METHODS

All singleton children (n = 797,318) born in Sweden between 1 July 2005 and 30 September 2013 were included and monitored to 31 December 2014. Cox proportional hazards models, adjusted for parental and perinatal characteristics, were applied, and stratified models were used to account for unmeasured confounders shared by siblings.

RESULTS

Type 1 diabetes developed in 1,297 children during the follow-up (median 4.0 years [range 0-8.3]). Prescribed antibiotics in the 1st year of life (23.8%) were associated with an increased risk of type 1 diabetes (adjusted hazard ratio [HR] 1.19 [95% CI 1.05-1.36]), with larger effect estimates among children delivered by cesarean section (P for interaction = 0.016). The association was driven by exposure to antibiotics primarily used for acute otitis media and respiratory tract infections. Further, we found an association of antibiotic prescriptions in pregnancy (22.5%) with type 1 diabetes (adjusted HR 1.15 [95% CI 1.00-1.32]). In general, sibling analysis supported these results, albeit often with statistically nonsignificant associations.

CONCLUSIONS

Dispensed prescription of antibiotics, mainly for acute otitis media and respiratory tract infections, in the 1st year of life is associated with an increased risk of type 1 diabetes before age 10 years, most prominently in children delivered by cesarean section.

Familial Coaggregation of Asthma and Type 1 Diabetes in Children

IMPORTANCE

The association between atopic and autoimmune disease, particularly asthma and type 1 diabetes, has been debated. Further understanding of the underlying factors associated with the comorbidity in children is warranted.

OBJECTIVES

To assess the bidirectional association between asthma and type 1 diabetes and examine the possibility of a shared risk for the diseases by studying their pattern of familial coaggregation.

DESIGN, SETTING, AND PARTICIPANTS

A birth cohort study of children born from January 1, 2001, and followed up until December 31, 2015, was performed. Population data were obtained from multiple national Swedish registers. A total of 1 347 901 singleton children, live-born in Sweden between January 1, 2001, and December 31, 2013, were identified, and children with incomplete data were excluded. The remaining 1 284 748 children were linked to their biological full siblings, maternal and paternal half-siblings, cousins, and half-cousins. Data analysis was conducted from April 1, 2019, to January 17, 2020.

MAIN OUTCOMES AND MEASURES

Cases of asthma and type 1 diabetes were defined using a combination of diagnoses and medication prescriptions found in the registers.

RESULTS

In the cohort of 1 284 748 children, 660 738 children (51.4%) were boys; 121 809 children (9.5%) had asthma, 3812 children (0.3%) had type 1 diabetes, and 494 children had both asthma and type 1 diabetes, representing 0.4% of all asthma or 13% of all type 1 diabetes. Mean (SD) age at diagnosis was 3.0 (2.8) years for children with asthma, and 5.9 (3.3) years for those with type 1 diabetes. Asthma and type 1 diabetes were associated within individuals (odds ratio, 1.15; 95% CI, 1.05-1.27). Children with asthma had an increased risk of subsequent type 1 diabetes (hazard ratio, 1.16; 95% CI, 1.06-1.27); however, subsequent asthma risk did not differ substantially among children with type 1 diabetes (hazard ratio, 0.92; 95% CI, 0.75-1.12). Siblings of individuals with asthma were at an increased risk of type 1 diabetes (odds ratio, 1.27; 95% CI, 1.13-1.42) and vice versa. The results remained positive after controlling for the direct association of one disease with the other.

CONCLUSIONS AND RELEVANCE

This study appears to provide evidence for co-occurrence, importance of sequential appearance, and coaggregation of asthma and type 1 diabetes in children and their siblings. The findings may suggest shared familial factors contributing to the associations. Knowledge of the nature of the association could be of importance in future clinical practice.

Type 1 diabetes-early life origins and changing epidemiology

Type 1 diabetes is a chronic, immune-mediated disease characterised by the destruction of insulin-producing cells. Standardised registry data show that type 1 diabetes incidence has increased 3-4% over the past three decades, supporting the role of environmental factors. Although several factors have been associated with type 1 diabetes, none of the associations are of a magnitude that could explain the rapid increase in incidence alone. Moreover, evidence of changing prevalence of these exposures over time is insufficient. Multiple factors could simultaneously explain the changing type 1 diabetes incidence, or the magnitude of observed associations could have been underestimated because of exposure measurement error, or the mismodelling of complex exposure-time-response relationships. The identification of environmental factors influencing the risk of type 1 diabetes and increased understanding of the cause at the individual level, regardless of the ability to explain the changing incidence at the population level, is important because of the implications for prevention.