Family characteristics and insulin dependent 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.

The effects of advanced maternal age on T-cell subsets at the maternal-fetal interface prior to term labor and in the offspring: a mouse study

Women who conceive at 35 years of age or older, commonly known as advanced maternal age, have a higher risk of facing parturition complications and their children have an increased risk of developing diseases later in life. However, the immunological mechanisms underlying these pathological processes have yet to be established. To fill this gap in knowledge, using a murine model and immunophenotyping, we determined the effect of advanced maternal age on the main cellular branch of adaptive immunity, T cells, at the maternal-fetal interface and in the offspring. We report that advanced maternal age impaired the process of labor at term, inducing dystocia and delaying the timing of delivery. Advanced maternal age diminished the number of specific proinflammatory T-cell subsets [T helper type 1 (Th1): CD4⁺ IFN-γ⁺ , CD8⁺ IFN-γ⁺ and Th9: CD4⁺ IL-9⁺ ], as well as CD4⁺ regulatory T cells (CD4⁺ CD25⁺ FoxP3⁺ T cells), at the maternal-fetal interface prior to term labor. Advanced maternal age also altered fetal growth and survival of the offspring in early life. In addition, infants born to advanced-age mothers had alterations in the T-cell repertoire but not in CD71⁺ erythroid cells (CD3^- CD71⁺ TER119⁺ cells). This study provides insight into the immune alterations observed at the maternal-fetal interface of advanced-age mothers and their offspring.

Characteristics of familial type 1 diabetes: effects of the relationship to the affected family member on phenotype and genotype at diagnosis

AIMS/HYPOTHESIS

In previous studies, the risk of developing familial type 1 diabetes has been reported to be more than two times higher in the offspring of affected fathers than in those of affected mothers. We tested the hypothesis that index children with an affected father may have a more aggressive disease process at diagnosis than those with other affected first-degree relatives.

METHODS

A cross-sectional, observational study was performed using the Finnish Pediatric Diabetes Register. Clinical and metabolic characteristics, beta cell autoantibodies and HLA class II genetics were analysed from index children in Finland diagnosed before the age of 15 years between January 2003 and December 2016. Information on the presence of type 1 diabetes in first-degree relatives was collected at diagnosis using a structured questionnaire.

RESULTS

Out of 4993 newly diagnosed index children, 519 (10.4%) had familial type 1 diabetes. More than 5% (n = 253, 5.1%) had an affected father, 2.8% (n = 141) had an affected mother, 1.9% (n = 95) had an affected sibling and 0.6% (n = 30) had two or more affected family members. All clinical and metabolic variables were markedly poorer in children with sporadic vs familial diabetes. The index children with an affected father or mother were younger than those with an affected sibling (median age 7.59 vs 6.74 vs 10.73 years, respectively; p < 0.001). After age- and sex-adjusted analyses, index children with an affected father presented more often with ketoacidosis (9.7% vs 3.6%; p = 0.033) and had greater weight loss before diagnosis (3.2% vs 0%; p = 0.006) than those with an affected mother. Children with familial disease tested negative for all autoantibodies more often (3.5% vs 2.1%; p = 0.041) and had insulin autoantibodies more frequently (49.8% vs 42.2%; p = 0.004) than those with sporadic disease. Both major HLA risk haplotypes (DR3-DQ2 and DR4-DQ8) were more often lacking among children with sporadic vs familial disease (15.9% vs 11.2%; p = 0.006). The DR4-DQ8 haplotype was more frequent in the familial vs the sporadic group (75.7% vs 68.5%; p = 0.001) and especially among children with an affected father when compared with children with sporadic disease (77.5% vs 68.5%; p < 0.05). When comparing index children with affected parents diagnosed before or after the birth of the index child, a clear male preponderance was seen among the affected parents diagnosed before the birth of the index child (fathers 66.2% vs mothers 33.8%; p = 0.006), whereas the proportion of fathers and mothers was similar if type 1 diabetes was diagnosed after the birth of the index child.

CONCLUSIONS/INTERPRETATION

The more severe metabolic derangement at diagnosis in children with sporadic type 1 diabetes compared with those with familial type 1 diabetes was confirmed. The higher frequency of diabetic ketoacidosis and increased weight loss at diagnosis in index children with an affected father compared with an affected mother support the hypothesis that paternal type 1 diabetes is associated with more severe disease in the offspring than maternal diabetes. The sex difference seen between affected parents diagnosed before and after the birth of the index child supports the hypothesis that maternal insulin treatment protects against type 1 diabetes.

Current evidence on the associations of breastfeeding, infant formula, and cow's milk introduction with type 1 diabetes mellitus: a systematic review

Current evidence provides contradictory results in regards to the associations of breastfeeding or early introduction of cow's milk and formula with the development of type 1 diabetes (T1D). The aim of this systematic review was to evaluate the type of feeding, duration of breastfeeding, time of introduction of formula or cow's milk, and the potential impact on developing T1D. The literature search was conducted based on the standards outlined in the MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies and yielded a total of 161 studies, 28 of which were included in this review. Twenty seven of the included studies were case-control and one was a prospective cohort study. Eight of the studies indicated breastfeeding has a protective role against the development of T1D. Seven additional studies emphasized that a short period or absence of breastfeeding could be a risk factor for T1D development. The results of this systematic review indicate a short duration and/or a lack of breastfeeding may constitute a risk factor for the development of T1D later in life.

Early-pregnancy cytokines in mothers to children developing multiple, persistent islet autoantibodies, type 1 diabetes, or both before 7 years of age

PROBLEM

Increased levels of serum cytokines in early pregnancy may increase the risk of type 1 diabetes in the offspring.

METHOD OF STUDY

Early-pregnancy (between 10 and 16 gestational weeks) serum samples from non-diabetic index mothers (n = 48) of children who developed islet autoimmunity, type 1 diabetes, or both before 7 years of age were analyzed for IFN-γ, IL-10, IL-12, IL-13, IL-1β, IL-2, IL-4, IL-5, CXCL8, and TNF. Control mothers (n = 93) were matched for age, sampling date, and HLA-DQ genotypes.

RESULTS

IFN-γ (P = 0.02) and IL-1β (P = 0.04) were elevated in the index mothers. All cytokines except IL-4 were highly correlated (P < 0.0001). IFN-γ [OR 1.39 (1.04, 1.85), P = 0.026] and possibly IL-2 [OR 1.21 (0.99, 1.48), P = 0.057] in early pregnancy were associated with an increased risk of multiple, persistent islet autoantibodies, type 1 diabetes, or both before 7 years of age in the offspring. However, the statistical significance for IL-2 was lost in the logistic regression when adjusted for gestational length at delivery and parity.

CONCLUSION

Increased Th1 cytokine levels during early pregnancy might contribute to an increased risk of islet autoimmunity, type 1 diabetes, or both in the offspring.

Demographic, breast-feeding, and nutritional trends among children with type 1 diabetes mellitus

BACKGROUND

The pathogenesis of type 1 diabetes mellitus (T1DM) requires a genetic predisposition to particular environmental triggers that may activate mechanisms leading to progressive loss of pancreatic beta cells.

AIMS

We tried to compare the impact of some demographic and environmental factors and breast-feeding on children (aged < 18 years) with recent onset diabetes mellitus (≤1 year) with that on age, sex, and socioeconomic status-matched controls.

MATERIAL AND METHODS

A total of 43 consecutive patients (male, 24, mean age ± SD = 12.58 ± 9.6 years) and equal number of controls without diabetes mellitus or dysglycemia were included in this hospital-based case-control study.

RESULTS AND CONCLUSIONS

A distinct peak in the incidence noted in the early adolescence with segregation in the winter months. Our patients did not differ significantly from the controls with regard to birth order, mode of delivery, parental age, parental education, dietary practices, breast-feeding, and migration in the family. Growth characteristics and nutritional status were also similar. A population study with more power will be better equipped to answer such queries.

Birth weight, early weight gain, and subsequent risk of type 1 diabetes: systematic review and meta-analysis

Previous studies suggest that birth weight and weight gain during the first year of life are related to later risk of type 1 diabetes. The authors performed a systematic review and meta-analysis on these associations. Twelve studies involving 2,398,150 persons of whom 7,491 had type 1 diabetes provided odds ratios and 95% confidence intervals of type 1 diabetes associated with birth weight. Four studies provided data on weight and/or weight gain during the first year of life. High birth weight (>4,000 g) was associated with increased risk of type 1 diabetes (odds ratio = 1.17, 95% confidence interval (CI): 1.09, 1.26). According to sensitivity analysis, this result was not influenced by particular study characteristics. The pooled confounder-adjusted estimate was 1.43 (95% CI: 1.11, 1.85). No heterogeneity was found (I(2) = 0%) and no publication bias. Low birth weight (<2,500 g) was associated with a nonsignificantly decreased risk of type 1 diabetes (odds ratio = 0.82, 95% CI: 0.54, 1.23). Each 1,000-g increase in birth weight was associated with a 7% increase in type 1 diabetes risk. In all studies, patients with type 1 diabetes showed increased weight gain during the first year of life, compared with controls. This meta-analysis indicates that high birth weight and increased early weight gain are risk factors for type 1 diabetes.

Family history of diabetes, autoimmunity, and risk factors for cardiovascular disease among children with diabetes in the SEARCH for Diabetes in Youth Study

BACKGROUND

While type 1 diabetes and type 2 diabetes (T2D) are considered etiologically distinct, mixed features of autoimmunity and insulin resistance are increasingly common. We explored a familial contribution to this admixture by evaluating diabetes family history (FH) and its relationship to diabetes type, ethnicity, age at diagnosis, and cardiovascular risk factors in SEARCH for Diabetes in Youth Study participants.

METHODS

Diabetes FH was assessed by questionnaire, with FH categories defined by relative's(s') age at diagnosis as follows: <25 (early FH), >/=25 (later FH), and both <25 and >/=25 (mixed FH). Diabetes type was classified based on a biochemical algorithm using diabetes autoantibodies and fasting C-peptide (FCP).

RESULTS

A positive FH was common in all diabetes types, particularly T2D (83%). Minorities were more likely to have a positive FH than non-Hispanic Whites [odds ratio (OR) 1.96, 95% confidence interval (CI) 1.69-2.27]. The likelihood of having an early FH decreased with age at diagnosis (OR 0.95, 95% CI 0.93-0.98), and the likelihood of having a later/mixed or any positive FH increased with age (OR 1.03, 95% CI 1.01-1.04; OR 1.03, 95% CI 1.02-1.05, respectively). Higher FCP concentrations and less desirable values for almost all cardiovascular risk factors were associated with a later/mixed FH. The association between a later/mixed FH and FCP, body mass index, waist circumference, triglycerides, and high-density lipoprotein remained significant in a subgroup of autoimmune participants.

CONCLUSIONS

Later FH confers cardiovascular risk factors in diabetic youth, including those youth with islet cell autoimmunity. This characterization of diabetes FH may provide a better understanding of familial contributors to diabetes.

Perinatal factors associated with subsequent diabetes mellitus in the child: record linkage study

AIMS

To report on associations between perinatal factors and the subsequent development of diabetes mellitus under the age of 30 years in the offspring.

METHODS

Analysis of linked hospital statistical records, comparing perinatal factors relating to the birth of 518 people admitted to hospital for diabetes with the same factors in 292 845 others, in a defined population in southern England from 1963 to 1999.

RESULTS

Diabetes mellitus was much more common in children of mothers with diabetes than in others (odds ratio 6.42; 95% confidence interval 4.18-9.86). There was no significant association with birthweight or gestational age separately. Diabetes was more common in those in the highest quintile of 'birthweight for gestational age' compared with the lowest four quintiles combined (odds ratio 1.33; 95% confidence interval 1.08-1.64), but there was no consistent gradient of increasing frequency of diabetes across the lowest four quintiles. There were no significant associations between diabetes and mothers' age, parity, social class, or smoking during pregnancy, or between babies' mode of delivery or any other perinatal factors investigated. All results were similar when the analysis was confined to diabetes in people aged < 15 years.

CONCLUSIONS

We found a strong association between diabetes in the child-mainly, if not entirely Type 1 diabetes-and maternal diabetes. Diabetes was slightly more common in the heaviest quintile of birthweight for gestational age than in other quintiles. There were no significant associations between diabetes and the other perinatal factors studied.

Socioeconomic conditions and type 1 diabetes in childhood in North Rhine-Westphalia, Germany

AIMS/HYPOTHESIS

The aim of the study was to investigate the relationships between childhood type 1 diabetes and socioeconomic conditions, which might provide clues to the aetiology of the disease.

MATERIALS AND METHODS

In an ecological study, we investigated the relationships between socioeconomic conditions and the incidence of type 1 diabetes incidence among children aged 0-14 years in North Rhine-Westphalia (NRW), Germany, between 1996 and 2000 at the level of the 33 districts. Incidence data were obtained from the population-based NRW diabetes register and regional socioeconomic data from official statistics. Associations were assessed by Poisson regression models and Bayesian conditionally autoregressive regression models (CAR).

RESULTS

In simple Poisson regression, population density, proportion of non-German nationals in the population, measures of income, education and professional training, and deprivation scores were significantly associated with diabetes risk (p < 0.01). An increase of about one interquartile range (IQR) in population density, proportion of non-German nationals or household income was associated with a 9-12% decrease in diabetes incidence. A rise of about one IQR in income ratio, measures of education and professional training, or in deprivation score (high values correspond to high deprivation) was associated with an 8-12% incidence increase. There was a significantly 'linear' increasing incidence trend across five deprivation classes (relative risk: 1.06; 95% CI: 1.03-1.09). All associations were confirmed when overdispersion and spatial autocorrelation were accounted for in Poisson and CAR models.

CONCLUSIONS/INTERPRETATIONS

The results raise the possibility that the risk for type 1 diabetes is higher for children living in socially deprived and less densely populated areas. Subsequent investigations are necessary to verify the observed ecological relations at the individual level and to identify the causal factors behind the socioeconomic indicators.

Clinical presentation of type 1 diabetes

OBJECTIVE

To identify the presenting features of type 1 diabetes in a national incident cohort aged under 15 yr, the duration of symptoms, the occurrence of diabetic ketoacidosis (DKA) at presentation, and the frequency of a family history of diabetes.

METHODS

A prospective study was undertaken of incident cases of type 1 diabetes using an active monthly reporting card system from January 1, 1997 to December 31, 1998 in the Republic of Ireland. Follow-up questionnaires were distributed to pediatricians nationally.

RESULTS

Two hundred and eighty-three incident cases were identified. Polyuria, polydipsia and weight loss were the main presenting symptoms in all age categories. Nocturnal enuresis was reported in 19% under 5 yr and in 31% aged 5-9.99 yr. Constipation was noted in five patients and in 10.4% under 5 yr of age. The median duration of symptoms was highest in the youngest (under 2 yr) and oldest (10-14.99 yr) age categories. Presentation in moderate/severe DKA occurred in 25% overall and six of nine of those aged under 2 yr. A family history of type 1 diabetes in a first-degree relative was found in 10.2%.

CONCLUSIONS

This study confirms the abrupt onset of type 1 diabetes, the absence of a family history, and the importance of the classical symptoms of polyuria, polydipsia, and weight loss in the majority of cases. It reveals secondary enuresis as an important symptom, especially in those under 10 yr, and constipation in the under 5 yr age group. The very young (under 2 yr) are more difficult to diagnose, have more variability of symptom duration, and are more likely to present in moderate/severe DKA. A high index of suspicion aids early diagnosis.

Parental age at delivery, birth order, birth weight and gestational age are associated with the risk of childhood Type 1 diabetes: a UK regional retrospective cohort study

AIMS

To investigate perinatal risk factors for childhood Type 1 diabetes in a UK population cohort.

METHODS

Perinatal data have been routinely recorded in Northern Ireland for all births in the period 1971-86 (n = 447 663). Diabetes status at the age of 15 years was ascertained in this cohort by identifying 991 children from 1079 registered with Type 1 diabetes diagnosed from 1971 to 2001 and date of birth in the period 1971-86.

RESULTS

Increased Type 1 diabetes risk was associated with higher maternal age, paternal age, birth weight and birth weight for gestational and lower gestational age. After adjustment for maternal age, the association between Type 1 diabetes and paternal age remained significant [relative risk (RR) = 1.52 (1.10, 2.09) comparing father's age 35 years or more to less than 25 years] but not vice versa [RR = 1.11 (0.80, 1.54) comparing mother's age 35 years or more to less than 25 years]. Increased birth order was associated with a significant decrease in the risk of Type 1 diabetes [adjusted RR = 0.75 (0.62, 0.90) comparing birth order three or more with firstborn], but this only became apparent when adjustment was made for maternal age. Furthermore this association with birth order was significant only for diabetes diagnosed under the age of 5 years.

CONCLUSIONS

Our analysis demonstrates, for the first time in a UK regional cohort setting, that maternal age and paternal age at delivery, birth order, birth weight and gestational age are significantly associated with Type 1 diabetes risk.

Nutritional risk predictors of beta cell autoimmunity and type 1 diabetes at a young age

Type 1 diabetes is an immune-mediated disease characterized by a preclinical prodrome during which beta cell autoimmunity proceeds at a variable rate. Large geographic differences and a conspicuous increase in incidence, especially among young children since the 1950s, and the relatively low concordance in identical twins are factors that favor a critical role of environmental factors in the etiology of this disease. Only approximately 5% or fewer subjects with HLA-conferred genetic susceptibility to type 1 diabetes actually develop the clinical disease. Breastfeeding, nicotinamide, zinc, and vitamins C, D, and E have been reported as possibly protecting against type 1 diabetes, whereas N-nitroso compounds, cow milk, increased linear growth, and obesity may increase the risk. Thus far, only the significance of infant feeding, cow milk, and vitamin D have been studied in both case-control and cohort settings. The major shortcoming of most studies done so far is that only single dietary exposures have been assessed at single time points. Putative nutritional and other confounding factors have received little attention as have the limitations of the dietary methods used. There is little firm evidence of the significance of nutritional factors in the etiology of type 1 diabetes. The availability of good markers of preclinical type 1 diabetes and of genetic risk have decreased the sample sizes needed and made longitudinal cohort studies of the assessment of children's diets feasible.

Preferential transmission of type 1 diabetes from parents to offspring: fact or artifact?

It has been widely reported that men with type 1 diabetes (T1D) tend to be more likely to transmit the disease to their offspring than their female counterparts in Caucasoid populations. Several theories to explain this preferential transmission have been proposed, but so far none of them has been unequivocally proven. Whatever the mechanism, confirmation or refutation of this observation is nonetheless important and practical to the design of future genetic studies of T1D. We carried out some statistical modeling of the preferential transmission. The well-established fact that males have higher a prevalence of T1D than females, an apparent sex difference in fecundity, and a possible misclassification of gestational diabetes mellitus (GDM) as T1D in women have been considered. We demonstrated, first, that the ascertainment of study families through the affected offspring with T1D would generate a higher proportion of fathers than mothers having T1D, even though there was no preferential transmission at all. This can be explained by the male preponderance in T1D prevalence as compared with females, coupled with a greater likelihood of being selected and/or recruited for study in families with T1D fathers due to the fecundity difference. Second, when the study population is ascertained through affected parents, misclassification of mothers with GDM as T1D, and the existence of male/female difference in fecundity in conjunction with a birth order effect, can contribute to the observed preferential transmission, even though there was none. In light of the plausibility of assumptions employed in the analysis and, in particular, an apparent failure to critically examine the effects of these causes of bias in earlier studies, it is perhaps prudent to say that the jury for the existence of preferential transmission in T1D is still out.

Behavior, heredity, and diabetes in college alumnae

OBJECTIVE

Diabetes has been increasing in incidence and prevalence in the United States. Physical activity and exercise have been shown to lower the risk of noninsulin-dependent diabetes (NIDD), and family history and genetic factors are associated with both insulin-dependent diabetes (IDD) (type 1) and NIDD. The objective of this paper is to examine risk factors for diabetes in female college graduates as part of a study designed to determine the long-term health of former college athletes compared with nonathletes. The study was first conducted in 1981-1982, and a follow-up study was conducted in 1996-1997.

METHODS

The subjects for this paper are 3940 college alumnae (1945 former athletes and 1995 nonathletes), who participated in the follow-up study by responding to a self-administered questionnaire on medical history, health, family history, and behavioral practices.

RESULTS

About 1.3% of the women reported physician-diagnosed diabetes, 0.9% of the former athletes, and 1.7% of the nonathletes. Former athletes had a significantly lower risk of NIDD, with an age-adjusted odds ratio (OR) of 0.41, 95% confidence level (CL) 0.2, 0.9. IDD was associated with a history of paternal diabetes (OR = 4.7, 95% CL 1.5, 14.9) and also with a history of diabetes in siblings (OR = 6.7, 95% CL 1.5, 30.1). NIDD was associated with a history of maternal diabetes (OR = 8.0, 95% CL 3.6, 17.8). Behavioral factors showed no association with IDD but were inversely associated with NIDD. The OR for being an athlete was 0.4, 95% CL 0.2, 0.9; for current regular exercise, OR = 0.4, 95% CL 0.2, 0.9; low body mass index (BMI) compared to high BMI, OR = 0.2, 95% CL 0.05, 0.60.

CONCLUSIONS

The findings that IDD is associated with paternal diabetes and that NIDD may be maternally transmitted are not widely known, although the mode of transmission of diabetes is receiving increasing attention in the medical and genetic literature. This study confirms that modifiable behavioral practices, such as physical activity and weight control (i.e., optimal BMI), reduce the risk of NIDD.

High familial risk and genetic susceptibility in early onset childhood diabetes

Early onset type 1 diabetes is associated with rapid beta-cell failure and high levels of HLA-mediated genetic susceptibility. We examined familial risk of disease in relation to age at onset in 1,299 families participating in the Bart's Oxford population-based family study of type 1 diabetes. Risk of diabetes was estimated by survival analysis in 1,430 siblings and 2,419 parents and related to age at onset in the proband. Unaffected relatives at high risk were identified by measurement of islet autoantibodies, and HLA class II genotyping was performed in probands where DNA was available (573 children). The cumulative risk of diabetes by age 20 years was 11.7% in siblings of probands diagnosed before age 5 years, compared with 3.6% for ages 5-9 years and 2.3% for ages 10-14 years (P < 0.0001). In parents, the cumulative risk by age 40 years was 5.9% if the proband was diagnosed before age 5 years, compared with 3.7% for ages 5-9 years and 3.7% for ages 10-14 years (P = 0.04). Of 1,169 unaffected siblings tested at study entry, 7.3% had two or more autoantibody markers if the proband was diagnosed before age 5 years, compared with 2.2 and 2.4%, respectively, for ages 5-9 and 10-14 years (P = 0.002). The frequency of the highest risk genotype decreased with increasing age at onset. Of children diagnosed before age 5 years, 52% were heterozygous for HLA DRB1*03-DQA1*0501-DQB1*02/DRB1*04-DQA1*0301-DQB1*0302 compared with 32% and 33%, respectively, for children diagnosed at ages 5-9 and 10-14 years (P < 0.001). Diabetes with onset before age 5 years is therefore a marker of high familial risk.

Uma amostra de pacientes com diabetes tipo 1 no sul do Brasil

Objetivos: Descrever uma população de pacientes com diabetes tipo 1 (DM1) em relação a fatores demográficos, ambientais, sócio-econômicos e manejo da doença. Delineamento: Série de casos. Participantes: Indivíduos com DM1, com até 10 anos de doença, até 30 anos de idade, residentes em onze municípios do sul do Brasil. Resultados: Foram estudados 126 indivíduos com DM1 (57 homens e 69 mulheres), sendo que a idade mais freqüente de início da doença foi dos 11 aos 15 anos (31%). Houve variação sazonal na época de apresentação. O diagnóstico foi feito por sintomas que motivaram uma dosagem de glicemia em 61%, por hospitalização, não em UTI, em 22% e por cetoacidose em 18%. Na amostra, 47% aplicava insulina uma vez ao dia. Sessenta por cento dos pacientes realizava algum tipo de automonitorização, um terço reutilizava seis ou mais vezes a seringa e 50% da insulina era fornecida pelo poder público. Quanto ao reconhecimento da hipoglicemia, 18% dos pacientes não sabiam citar nenhum dos sinais de alerta. Grande parte da amostra (73%) consultava médico especialista em DM. Dos pacientes com mais de 5 anos de doença, 16% nunca haviam feito fundoscopia e 17% haviam realizado o exame há 2 anos ou mais. As formas de apresentação da doença e da aquisição de insulina e a consulta com especialista estiveram associadas à renda familiar. As mulheres seguiam a dieta de modo mais adequado (p= 0,05) e auto-aplicavam insulina com mais freqüência, quando comparadas aos homens. Conclusões: Os fatores sócio-econômicos influenciaram neste estudo a forma de diagnóstico da doença, a obtenção de insulina e o acesso à especialistas. Os pacientes ainda carecem de conhecimentos básicos a respeito do manejo da doença.

Birth weight and childhood onset type 1 diabetes: population based cohort study

OBJECTIVE

To assess the associations between birth weight or gestational age and risk of type 1 diabetes.

DESIGN

Population based cohort study by record linkage of the medical birth registry and the National Childhood Diabetes Registry.

SETTING

Two national registries in Norway.

PARTICIPANTS

All live births in Norway between 1974 and 1998 (1 382 602 individuals) contributed a maximum of 15 years of observation, a total of 8 184 994 person years of observation in the period 1989 to 1998. 1824 children with type 1 diabetes were diagnosed between 1989 and 1998.

MAIN OUTCOME MEASURES

Estimates of rate ratios with 95% confidence intervals for type 1 diabetes from Poisson regression analyses.

RESULTS

The incidence rate of type 1 diabetes increased almost linearly with birth weight. The rate ratio for children with birth weights 4500 g or more compared with those with birth weights less than 2000 g was 2.21 (95% confidence interval 1.24 to 3.94), test for trend P=0.0001. There was no significant association between gestational age and type 1 diabetes. The results persisted after adjustment for maternal diabetes and other potential confounders.

CONCLUSION

There is a relatively weak but significant association between birth weight and increased risk of type 1 diabetes consistent over a wide range of birth weights.

Breastfeeding and chronic disease in childhood and adolescence

A growing body of research suggests that infant feeding practices influence the risk for several chronic diseases of childhood and adolescence. Increased risks for type 1 diabetes, celiac disease, some childhood cancers, and inflammatory bowel disease have been associated with artificial infant feeding and short-term breastfeeding. As genetic susceptibility is understood more completely and gene-environment interactions are elucidated, evidence to either confirm or refute these findings will be forthcoming.

Influence of maternal age at delivery and birth order on risk of type 1 diabetes in childhood: prospective population based family study. Bart's-Oxford Family Study Group

OBJECTIVES

To examine the influence of parental age at delivery and birth order on subsequent risk of childhood diabetes.

DESIGN

Prospective population based family study.

SETTING

Area formerly administered by the Oxford Regional Health Authority.

PARTICIPANTS

1375 families in which one child or more had diabetes. Of 3221 offspring, 1431 had diabetes (median age at diagnosis 10.5 years, range 0.4-28.5) and 1790 remained non-diabetic at a median age of 16. 1 years.

MAIN OUTCOME MEASURES

Disease free survival and hazard ratios for the development of type 1 diabetes in all offspring, assessed by Cox proportional hazard regression.

RESULTS

Maternal age at delivery was strongly related to risk of type 1 diabetes in the offspring; risk increased by 25% (95% confidence interval 17% to 34%) for each five year band of maternal age, so that maternal age at delivery of 45 years or more was associated with a relative risk of 3.11 (2.07 to 4.66) compared with a maternal age of less than 20 years. Paternal age was also associated with a 9% (3% to 16%) increase for each five year increase in paternal age. The relative risk of diabetes, adjusted for parental age at delivery and sex of offspring, decreased with increasing birth order; the overall effect was a 15% risk reduction (10% to 21%) per child born.

CONCLUSIONS

A strong association was found between increasing maternal age at delivery and risk of diabetes in the child. Risk was highest in firstborn children and decreased progressively with higher birth order. The fetal environment seems to have a strong influence on risk of type 1 diabetes in the child. The increase in maternal age at delivery in the United Kingdom over the past two decades could partly account for the increase in incidence of childhood diabetes over this period.

Cytokines (IL-1beta, IL-6, TNF-alpha, TGF-beta1, and TGF-beta2) and prostaglandin E2 in human milk during the first three months postpartum

Postpartum changes in the concentrations of IL-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta1 (TGF-beta1), TGF-beta2, and prostaglandin E2 in 257 human milk samples collected longitudinally from 49 healthy mothers during the first 12 wk of lactation were determined by ELISA or RIA. The proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha were present in only a proportion of samples, and there was a wide range of concentrations detected at each time in the present study (IL-1beta, <15-400 pg/mL; IL-6, <15-1032 pg/mL; TNF-alpha, <15-2933 pg/mL). Concentrations of prostaglandin E2 increased after the first week and remained elevated for the remainder of the study (range, < 10-9966 pg/mL). The antiinflammatory cytokines TGF-beta1 (range, 43-7108 pg/mL) and TGF-beta2 (range, 208-57935 pg/mL) were present in substantial quantities in all samples, and there was little change in the mean concentration during 12 wk of lactation. The present study shows that immunomodulating agents are normally present in human milk in physiologically relevant quantities for at least the first 3 mo of the breast-fed infant's life.

Amamentação ao seio, amamentação com leite de vaca e o diabetes mellitus tipo 1: examinando as evidências

A etiologia do diabetes mellitus tipo 1 (DM1) envolve tanto herança genética como a exposição a fatores ambientais. Evidências de estudos epidemiológicos e experimentais sugerem que a dieta pode ser importante na etiopatogenia dessa doença. Em 1984, Borch-Johnsen e col. sugeriram, com base nos resultados de um estudo caso-controle, que o leite materno seria um fator de proteção para o DM1; esse efeito se daria devido às propriedades anti-infecciosas desse tipo de leite, ou pelo fato de que a amamentação ao seio evitaria que as crianças pudessem ser precocemente expostas a outros agentes etiológicos contidos nos substitutos do leite materno. Esses mesmos achados foram poste-riormente encontrados em diversos estudos, mas o papel do leite materno no aparecimento do DM1 ainda permanece controverso. Em 1992, Karjalainen e col., ao compararem os soros de indivíduos com e sem DM1, observaram, entre os diabéticos, altas concentrações de anticorpos anti-albumina bovina. Os autores postularam a hipótese de que a albumina bovina poderia atuar como desencadeadora do processo destrutivo das células ß do pâncreas e, conseqüentemente, do diabetes. Resultados conflitantes foram observados nas publicações que se sucederam a essa. Neste artigo, resumem-se e discutem-se os achados de diferentes pesquisadores que investigaram a importância desses fatores dietéticos para o aparecimento do DM1.

Special properties of human milk

In this review, several nutritional and nonnutritive differences between mothers' milk and formula and their relationship to neonatal gastrointestinal and immune processes are discussed. The dynamic relationship of human milk as evidenced by its changing composition, unique bioactive and immunologic properties, and specialized cellular components is further delineated. The clinical significance and relevance of these findings to the clinician are then presented. Lastly, educational strategies, their effectiveness in promoting breastfeeding, and an approach that might be taken by the clinician to encourage breastfeeding are outlined.

Dietary factors in the aetiology of diabetes

Quite different nutrition-related environmental factors influence the development of type 1 insulin-dependent diabetes (IDDM) and type 2 non-insulin-dependent diabetes (NIDDM). IDDM is characterized by progressive beta-cell destruction which leads to complete insulin deficiency; at the time of diagnosis 80-90% of beta cells have been destroyed. In children there is epidemiological evidence that high intake of nitrites and N-nitroso compounds, early introduction of cow's milk to the diet and short duration or absence of breastfeeding increase the risk of IDDM. Studies in experimental animals suggest that cow's milk and soy proteins may be diabetogenic. There is current interest in the effects of free radical scavengers, particularly niacin and natural and synthetic antioxidants on the incidence of IDDM. These findings from ecological, animal, and human case-control studies remain to be evaluated in prospective cohort studies covering infancy and childhood and finally in human intervention trials. NIDDM is characterized by insulin resistance which is complicated by impaired insulin secretion at the time of appearance of hyperglycaemia and clinical diabetes. Its preclinical development is insidious and poorly defined, and there is little direct evidence that the same factors which influence metabolic control in clinical diabetes also affect the preclinical development of the disorder. Obesity, particularly of the abdominal type, is common in people who develop NIDDM, and weight control by appropriate diet and physical activity is probably the most important measure for preventing NIDDM. High (saturated) fat intake seems to be associated with insulin resistance, obesity and increased risk of NIDDM, and diets high in carbohydrate seem to protect from glucose intolerance and diabetes, mainly owing to their high fibre content.