A case-control investigation of perinatal risk factors for childhood IDDM in Northern Ireland and Scotland

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.

No association between preeclampsia or cesarean section and incidence of type 1 diabetes among children: a large, population-based cohort study

The objective was to investigate whether selected perinatal factors, as indicators of perinatal exposures, are associated with the risk of type 1 diabetes in children. Specifically, we tested whether maternal preeclampsia, Rhesus-immunization, induced labor, cesarean section, and multiple birth were associated with incidence of type 1 diabetes. A cohort study was designed by linking records of the Medical Birth Registry and the National Childhood Diabetes Registry of Norway. Live births in the study period were followed for a maximum of 15 y and contributed 8,166,731 person-years between 1989 and 1998. Altogether, 1824 cases of type 1 diabetes diagnosed between 1989 and 1998 were identified within the cohort. There was a suggestive, but nonsignificant, increase in risk of type 1 diabetes associated with Rhesus-immunization. Maternal preeclampsia, cesarean section, and the other perinatal factors investigated in this study were not significantly associated with incidence of type 1 diabetes in the children. Previous indications that cesarean section and preeclampsia are associated with type 1 diabetes were not supported by this large study. The majority of routinely recorded perinatal factors are only weakly associated with type 1 diabetes, or not at all.

Diabetes in the young: a paediatric and epidemiological perspective

The spectrum of diabetes in the young has widened; it now includes monogenic diseases, for example the various forms of permanent and transient neonatal diabetes and MODY as well as the emerging obesity-associated Type 2 diabetes in late childhood, but the main form is still Type 1 diabetes. Age-related major medical, physiological, social and emotional problems make the clinical management of diabetes in children and adolescents a difficult task for the physician and the family. Overall glycaemic control remains moderate or poor despite a treatment schedule, which interferes with several elements of "normal" childhood. There is an up to tenfold geographical variation in the incidence of childhood Type 1 diabetes within Europe with relatively stable incidence rates in some countries (mainly northern), but dynamic increases in incidence in other countries (mainly central European).A number of nongenetic (environmental) factors have been associated with the risk of Type 1 diabetes. Among these, perinatal factors, early nutrition, growth and vaccinations, atopic diseases and vitamin D are discussed in detail. The important interplay between genes, organism and environment is illustrated with new genetic data supporting the importance of environmental pressures in the evolution of this major disease.Although Type 1 diabetes usually accounts for only a minority of the total impact of diabetes in a population, it is the predominant form of the disease in younger age-groups in most developed countries. It is estimated that on an annual basis almost 100 000 children younger than 15 years of age develop Type 1 diabetes worldwide. The autoimmune destruction of the pancreatic beta cells in Type 1 diabetes leads to absolute insulin dependence and a high rate of complications typically occurring at a relatively young age. Therefore, Type 1 diabetes places a particularly heavy burden on the individual, the family and health services.

Increased risk of childhood type 1 diabetes in children born after 1985

OBJECTIVE

The incidence rate of childhood type 1 diabetes is thought to be increasing; however, Danish studies have not confirmed this. Using a national diabetes register initiated in 1996 and two previous regional incidence studies, we studied the age-specific incidence of type 1 diabetes over 30 years. Here, we describe the incidence rates of type 1 diabetes in Danish children from 1996 to 2000 and evaluate trends in age-specific incidence rates from 1970 to 2000.

RESEARCH DESIGN AND METHODS

A nationwide registration of all newly diagnosed cases of type 1 diabetes among children under the age of 15 years was established in Denmark in 1996. Incidence rates of type 1 diabetes in Denmark were obtained from this register. Age-specific incidence rates were compared with data collected from 1970 to 1976 and from 1980 to 1984, both population-based studies using existing national routine registration of hospitalizations within the survey areas. Population data were obtained from Statistics Denmark.

RESULTS

During the study period, 1,421 Danish children developed type 1 diabetes before the age of 15 years. The incidence rates by age-groups were: 12.7, 19.4, and 26.3 for the 0-4, 5-9, and 10-14 years age-groups, respectively, and 19.5 for the 0-14 years age-group per 100,000 in the period 1996-2000. An age-period-cohort analysis showed a modest drift effect (yearly increase) of 1.2% (0.7-1.8) from 1970 to 2000, and a significant birth cohort effect with an increased risk for children born after 1985 was observed.

CONCLUSIONS

The incidence rate of type 1 diabetes is rising in children living in Denmark. The steep increase in the youngest age-group was explained by the increased risk for cohorts born at the beginning of the 1980s.

Rapid early growth is associated with increased risk of childhood type 1 diabetes in various European populations

OBJECTIVE

To confirm that early growth is associated with type 1 diabetes risk in European children and elucidate any role of infant feeding.

RESEARCH DESIGN AND METHODS

Five centers participated, each with a population-based register of type 1 diabetes diagnosed at <15 years of age. Control subjects were randomly chosen from population registers, schools, or polyclinics. Growth data were obtained from routine records and infant feeding information from parental questionnaire or interview. Patient/control subject differences in mean standard deviation score (SDS) were obtained for each center and pooled. Odds ratios (ORs) were pooled by the Mantel-Haenszel method, and logistic regression was used to adjust for confounders.

RESULTS

Growth data were available for 499 patients and 1,337 control subjects. Height and weight SDS were significantly increased among patients from 1 month after birth, the maximum differences of 0.32 (95% CI 0.14-0.50) and 0.41 (0.26-0.55), respectively, occurring between 1 and 2 years of age. Significant excesses in BMI SDS were observed from 6 months of age, with the largest difference of 0.27 (0.10, 0.44) evident between 1 and 2 years. Breast-feeding was associated with reduced disease risk, OR 0.75 (0.58-0.96). Introduction of cow's milk, formula, or solid foods before 3 months was not associated with significant risk elevation.

CONCLUSION

Increased early growth is associated with disease risk in various European populations. Any role of infant feeding in this association remains unclear.

Coeliac disease is associated with intrauterine growth and neonatal infections

To investigate whether factors in the fetal or neonatal period influence the risk of later development of coeliac disease we conducted a population-based register study. The Swedish Medical Birth Register was linked with the Hospital Discharge Register and identified 3392 singleton infants born in the period 1987-97 who developed coeliac disease. Perinatal data for these children were compared with all children born in these years. Exposure variables: Maternal age, parity and smoking habits in early pregnancy, preeclampsia, pregnancy duration and birthweight, birthweight by gestational week, Apgar score, neonatal icterus, neonatal infections, maternal-fetal blood group incompatibility, exchange transfusion, phototherapy. Odds ratios and test-based confidence intervals were calculated. Analyses were made with stratification for year of birth and other risk factors. The risk of developing coeliac disease decreased with maternal age and was lower in first-born than in second-born children. Maternal smoking in early pregnancy was a weak risk factor, as was low birthweight. The most evident risk factors were being exposed to neonatal infections (OR = 1.52, confidence limits 1.19: 1.95) and being small for gestational age (OR = 1.45, confidence limits 1.20; 1.75). These risk factors were independent of each other.

CONCLUSIONS

We have demonstrated that the intrauterine environment, mainly as mirrored by a low birthweight for gestational age and, independently, neonatal infection diagnosis, is associated with the risk of developing coeliac disease, supporting the idea of a multifactorial aetiology of the disease.

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.

Maternal and paternal age at delivery, birth order, and risk of childhood onset type 1 diabetes: population based cohort study

OBJECTIVE

To estimate the associations of maternal and paternal age at delivery and of birth order with the risk of childhood onset type 1 diabetes.

DESIGN

Cohort study by record linkage of the medical birth registry and the national childhood diabetes registry in Norway.

SETTING

Norway.

SUBJECTS

All live births in Norway between 1974 and 1998 (1.4 million people) were followed for a maximum of 15 years, contributing 8.2 million person years of observation during 1989-98. 1824 cases of type 1 diabetes diagnosed between 1989 and 1998 were identified.

MAIN OUTCOME MEASURES

Incidence of type 1 diabetes.

RESULTS

There was no association between maternal age at delivery and type 1 diabetes among firstborn children, but among fourth born children there was a 43.2% increase in incidence of diabetes for each five year increase in maternal age (95% confidence interval 6.4% to 92.6%). Each increase in birth order was associated with a 17.9% reduction in incidence (3.2% to 30.4%) when maternal age was 20-24 years, but the association was weaker when maternal age was 30 years or more. Paternal age was not associated with type 1 diabetes after maternal age was adjusted for.

CONCLUSIONS

Intrauterine factors and early life environment may influence the risk of type 1 diabetes. The relation of maternal age and birth order to risk of type 1 diabetes is complex.

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.

Milk and diabetes

Type 1 diabetes is based on autoimmunity, and its development is in part determined by environmental factors. Among those, milk intake is discussed as playing a pathogenic role. Geographical and temporal relations between type 1 diabetes prevalence and cow's milk consumption have been found in ecological studies. Several case-control studies found a negative correlation between frequency and/or duration of breast-feeding and diabetes, but this was not confirmed by all authors. T-cell and humoral responses related to cow's milk proteins were suggested to trigger diabetes. The different findings of studies in animals and humans as well as the potential underlying mechanisms with regard to single milk proteins (bovine serum albumin, beta-lactoglobulin, casein) are discussed in this review. In contrast to type 1 diabetes, the etiology of type 2 diabetes, characterized by insulin resistance is still unclear. In a population with a high prevalence of type 2 diabetes, the Pima Indians, people who were exclusively breastfed had significantly lower rates of type 2 diabetes than those who were exclusively bottlefed. Studies in lactovegetarians imply that consumption of low fat dairy products is associated with lower incidence and mortality of diabetes and lower blood pressures. In contrast, preference for a diet high in animal fat could be a pathogenic factor, and milk and high fat dairy products contribute considerably to dietary fat intake. Concerning milk fat composition, the opposite effects of various fatty acids (saturated fatty acids, trans-fatty acids, conjugated linoleic acid) in vitro, in animals and in humans have to be considered.

Early social mixing and childhood Type 1 diabetes mellitus: a case-control study in Yorkshire, UK

AIMS

Evidence from animal models shows an increased risk of Type 1 diabetes mellitus associated with the absence of early life exposure to pathogens. To test this 'hygiene hypothesis', patterns of social mixing and infections in the first year of life and the risk of developing autoimmune diabetes in childhood were examined.

METHODS

Personal interviews were conducted with the mothers of 220 children with Type 1 diabetes (0-15 years) and 433 age/sex matched controls from a population-based case control study in Yorkshire, UK. Social mixing including attendance at daycare, and infections occurring under 1 year of age were measures of exposure. Adjusted odds ratios (OR) were derived using conditional logistic regression.

RESULTS

Frequency of attendance at daycare during the 1st year of life was inversely associated with childhood diabetes (OR 0.71, 95% confidence interval 0.51-1.00, P = 0.05), a finding not explained by mother's age, level of education or maternal diabetes. Increasing numbers of children in the daycare setting and numbers of sessions attended were significantly associated with increasing protection from diabetes. The strongest effect was observed in children with diabetes diagnosed aged 0-4 years.

CONCLUSIONS

Social mixing through attendance at daycare in early infancy appears to confer protection against the development of childhood diabetes. This may be mediated through exposure to infectious agent(s) as a significant dose-response effect was evident with increasing numbers of child 'contacts'. These findings suggest early infectious exposure may play a role in the development of immunoregulatory mechanisms which protect against diabetes and further work is warranted.

A case-control study on risk factors for Type 1 diabetes in Taipei City

To search for non-genetic risk factors for Type 1 diabetes among Chinese, a total of 117 Type 1 diabetes patients identified from the Taipei Type 1 Diabetes Registry and 193 frequency-matched controls with normal glucose tolerance were recruited. The controls were selected from classmates or colleagues of cases with similar distributions of age, sex, and parental and individual educational levels. Information on Type 1 diabetes risk factors was obtained through standardized interviews according to a structured questionnaire administered by two trained nurses. In the univariate analyses, the order of pregnancy of the study subject, the number of spontaneous and induced abortions reported by the mother before giving birth to the study subjects, the duration of breast-feeding and monthly family income were significantly associated with Type 1 diabetes in a dose-response manner. There was a U-shaped relationship with Type 1 diabetes for birth weight and paternal age at the conception of the study subjects. After further adjustment for multiple risk factors through logistic regression analysis, the biological gradient for pregnancy order, duration of breast-feeding, and the U-shaped relationship for paternal age remained statistically significant.

The aetiology of type 1 diabetes: an epidemiological perspective

Type 1 diabetes is increasing rapidly in many parts of the Western world, most evidently in Scandinavia. A low concordance rate of insulin-dependent diabetes mellitus among monozygotic twins clearly indicates that genetic risk factors may be necessary, but are not sufficient for the disease to occur. The strongest genetic risk markers are located in the HLA region of chromosome 6, but these DNA specificities differ in different populations. Risk genes are indicated in other chromosomes of the human genome, suggesting a complex interaction between genes and environment as the cause of the disease. The pathogenesis of the disease is proposed to be autoimmune in nature and environmental risk factors may either initiate autoimmunity or accelerate an already ongoing beta-cell destruction. Risk factors disclosed by epidemiological studies that may accelerate the pathogenetic process are: a cold environment, a high growth rate, infections and stressful life events. Risk factors that may initiate the autoimmune process include early exposure to cow's milk proteins, nitrosamines or early foetal events such as blood group incompatibility or foetal viral infections. In conclusion, population-based epidemiological studies have helped to confirm proposed aetiological models that have arisen from experimental research. These epidemiological studies have also introduced important new findings that may reveal the complex aetiology of the disease and advance understanding closer to the ultimate goal of primary prevention.

Epidemiology of childhood IDDM in Northern Ireland 1989-1994: low incidence in areas with highest population density and most household crowding. Northern Ireland Diabetes Study Group

During the period 1989-1994, 462 cases of insulin-dependent diabetes mellitus were registered among children from Northern Ireland aged under 15 years. The estimated completeness of the register was 98.8% (95% confidence interval (CI) 97.7%, 99.9%). A standardised rate of 19.6 (95% CI 17.8, 21.4) per 100 000 person years was obtained, placing Northern Ireland near the top of the range of published incidence in the United Kingdom, with a rate close to that reported for Scotland. In an analysis based on 217 postcode sectors, areas with a high population density and the most material deprivation were observed to have the lowest incidence rates. After inclusion of population density in a Poisson regression analysis, the component of deprivation which was found to be most significant was household crowding. Relative to children living in areas of low population density, there was a reduced risk for children in medium (relative incidence 0.85 (95% confidence limits CI 0.67, 1.09)) and high (0.62 (95% CI 0.48,0.80)) population density areas. Similarly, relative to children living in areas with low levels of household crowding, there was a reduced risk for children in medium (relative incidence 0.73 (95% CI 0.58,0.93)) and high (0.67 (95% CI 0.53, 0.83)) levels of household crowding. Tests for space-time clustering at diagnosis and at birth were negative. A possible explanation for the differences in incidence rate observed in this study is that exposure to infections very early in childhood is a protective factor. Later infections may act as either initiators or promoters of diabetes, but the absence of space-time clustering suggests that no single specific infectious agent is responsible.