Non-genetic risk determinants for type 1 (insulin-dependent) diabetes mellitus in childhood. Hungarian Childhood Diabetes Epidemiology Study Group

Is socio-economic status associated with risk of childhood type 1 diabetes? Literature review

AIMS

Studies of social inequality and risk of developing type 1 diabetes are inconsistent. The present review aimed to comprehensively review relevant literature and describe what has been reported on socio-economic status or parental occupation and risk of type 1 diabetes in children.

METHODS

We searched for publications between 1 January 1970 and 30 November 2021. We focused on the most recent and/or informative publication in cases of multiple publications from the same data source and referred to these as primary studies.

RESULTS

Our search identified 69 publications with relevant data. We identified eight primary cohort studies with individual-level data, which we considered the highest quality of evidence. Furthermore, we identified 13 primary case-control studies and 14 semi-ecological studies with area-level socio-economic status variables which provided a weaker quality of evidence. Four of eight primary cohort studies contained data on maternal education, showing non-linear associations with type 1 diabetes that were not consistent across studies. There was no consistent pattern on the association of parental occupation and childhood-onset type 1 diabetes.

CONCLUSIONS

There is a need for more high-quality studies, but the existing literature does not suggest a major and consistent role of socio-economic status in the risk of type 1 diabetes.

Accumulation of childhood adversities and type 1 diabetes risk: a register-based cohort study of all children born in Denmark between 1980 and 2015

BACKGROUND

Previous studies have indicated an association between childhood adversities and type 1 diabetes but have been underpowered and limited by selection. We aim to quantify the effect of accumulation of childhood adversities on type 1 diabetes risk, and to assess whether the effect differs between males and females in a large and unselected population sample.

METHODS

We used register-based data covering all children born in Denmark between 1980 and 2015, totalling >2 million children. We specified a multi-state model to quantify the effect of accumulation of childhood adversities on type 1 diabetes risk. The effects of specific childhood adversities on type 1 diabetes were estimated using proportional hazards models.

RESULTS

Accumulation of childhood adversities had a quantitatively small effect on type 1 diabetes risk among females [adjusted hazard ratio (HR) per adversity increase: 1.07; 95% confidence interval (CI): 1.02-1.11], but not among males (adjusted HR per adversity increase: 0.99; 95% CI: 0.97-1.03). Females exposed to extreme numbers (7+) of adversities had two times higher risk of type 1 diabetes compared with unexposed females (adjusted HR: 2.06; 95% CI: 1.10-3.86).

CONCLUSIONS

In an unselected total population sample, we generally find no or negligible effects of childhood adversities on type 1 diabetes risk, which may be reassuring to persons with type 1 diabetes who are concerned that personal trauma contributed to their disease. There is a very small group of females exposed to a high degree of adversity who may have a higher risk of type 1 diabetes and this group needs further attention.

Infant milk-feeding practices and diabetes outcomes in offspring: a systematic review

BACKGROUND

During the Pregnancy and Birth to 24 Months Project, the US Departments of Agriculture and Health and Human Services initiated a review of evidence on diet and health in these populations.

OBJECTIVES

The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding, and 4) feeding a lower versus higher intensity of human milk to mixed-fed infants with type 1 and type 2 diabetes in offspring.

METHODS

The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published January 1980-March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence.

RESULTS

The 4 systematic reviews included 21, 37, 18, and 1 articles, respectively. Observational evidence suggests that never versus ever feeding human milk (limited evidence) and shorter versus longer durations of any (moderate evidence) and exclusive (limited evidence) human milk feeding are associated with higher type 1 diabetes risk. Insufficient evidence examined type 2 diabetes. Limited evidence suggests that the durations of any and exclusive human milk feeding are not associated with intermediate outcomes (e.g., fasting glucose, insulin resistance) during childhood.

CONCLUSIONS

Limited to moderate evidence suggests that feeding less or no human milk is associated with higher risk of type 1 diabetes in offspring. Limited evidence suggests no associations between the durations of any and exclusive human milk feeding and intermediate diabetes outcomes in children. Additional research is needed on infant milk-feeding practices and type 2 diabetes and intermediate outcomes in US populations, which may have distinct metabolic risk.

Psychological stress and type 1 diabetes mellitus: what is the link?

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is a chronic disease characterized by the destruction of insulin-producing β-cells of the pancreas. The current paradigm in this disease's etiopathogenesis points toward the interplay of genetic and environmental factors. Among the environmental variables, dietary factors, intestinal microbiota, toxins, and psychological stress have been implicated in disease onset. Areas covered: This review aims to investigate the relationship between psychological stress and T1DM by presenting evidence from epidemiological studies, animal models, and to provide the mechanism involved in this association. The literature search was conducted through PubMed to identify studies that investigate the connection between stress and T1DM. Experimental designs, such as case-control, and retrospective and prospective cohorts studies, were included. Expert commentary: A wide array of evidence, ranging from epidemiological to animal models, points toward the role of psychological stressors in T1DM pathogenesis. Various mechanisms have been proposed, including the hypothalamic-pituitary-adrenal (HPA) axis, influence of the nervous system on immune cells, and insulin resistance. Further research could investigate the gene-stress interactions to evaluate the risk of T1DM development.

Systematic review and meta-analysis of the association between mumps during childhood and risk of type 1 diabetes mellitus

We conducted a systematic review and meta-analysis of the association between mumps and risk of type 1 diabetes mellitus (T1DM). Literature searches were conducted using Medline, EMBASE and Web of Science including studies published before February 2014. Crude and, where available, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were extracted from the published reports of each included study. Combined OR estimates and tests of heterogeneity were obtained using meta-analysis techniques. The analysis was repeated in subgroups of studies on the basis of quality defined by the score on the Newcastle-Ottawa scale (NOS). In total, 18 articles met the eligibility criteria, and overall there was some evidence of a weak association between clinically diagnosed mumps and T1DM (OR=1.23, 95% CI 1.00-1.51; p=0.05) but marked heterogeneity between studies (I2=49%; p for heterogeneity=0.01). Restricting analyses to 13 high quality studies, there was little evidence of association between clinically diagnosed mumps and T1DM (OR=1.11, 95% CI 0.91-1.35; p=0.29) and there was much less heterogeneity (I2=26%; p for heterogeneity=0.18). Overall there was little evidence of any strong association between mumps infection and T1DM.

Childhood Bereavement and Type 1 Diabetes: a Danish National Register Study

BACKGROUND

Death of a close family member such as a parent or a sibling can cause prolonged stress and changes in the family structure that may have extensive social and health effects on a young child. The aim of this paper is to examine the rate of type 1 diabetes following bereavement due to death of a first-degree family member in early life.

METHODS

We used data from the Danish Civil Registration System (CRS) to identify singleton births in Denmark born 1 January 1980 through 31 December 2005, n = 1 740 245 and their next of kin. We categorised children as exposed to bereavement if they lost a mother, father or sibling from age 5 years onwards, the remaining children were considered unexposed. Children were followed until first diagnosis of diabetes, death, emigration, or 31 December 2010. We estimated incidence rate ratios (IRRs) from birth using log-linear Poisson regression models with person-years as an offset variable. Exposed children were followed up for an average of 9.1 years [standard deviation (SD) 6.7] and unexposed children were followed up for an average of 12.3 years (SD 7.3).

RESULTS

In our sample 94 943 children were exposed to bereavement, and 6110 cases of type 1 diabetes were identified. Bereavement was associated with an increased rate of type 1 diabetes when exposure onset began after 11 years of age (adjusted IRR 1.28, 95% confidence interval 1.08, 1.51).

CONCLUSION

We found some evidence to indicate an increase in the rate of type 1 diabetes among children exposed to bereavement when exposure occurred after 11 years of age.

Does breastfeeding influence the risk of developing diabetes mellitus in children? A review of current evidence

OBJECTIVE

The aim of this study was to perform a review to investigate the influence of breastfeeding as a protective agent against the onset of diabetes in children.

SOURCES

non-systematic review of SciELO, LILACS, MEDLINE, Scopus, and VHL databases, and selection of the 52 most relevant studies. A total of 21 articles, specifically on the topic, were analyzed (nine related to type 1 diabetes and 12 to type 2 diabetes).

DATA SYNTHESIS

The duration and exclusivity of breastfeeding, as well as the early use of cow's milk, have been shown to be important risk factors for developing diabetes. It is believed that human milk contains substances that promote the maturation of the immune system, which protect against the onset of type 1 diabetes. Moreover, human milk has bioactive substances that promote satiety and energy balance, preventing excess weight gain during childhood, thus protecting against the development of type 2 diabetes. Although the above mentioned benefits have not been observed by some researchers, inaccuracies on dietary habit reports during childhood and the presence of interfering factors have been considered responsible for the lack of identification of beneficial effects.

CONCLUSION

Given the scientific evidence indicated in most published studies, it is believed that the lack of breastfeeding can be a modifiable risk factor for both type 1 and type 2 diabetes. Strategies aiming at the promotion and support of breastfeeding should be used by trained healthcare professionals in order to prevent the onset of diabetes.

Family psychological stress early in life and development of type 1 diabetes: the ABIS prospective study

AIMS

This study investigated whether psychological stress in the family during the child's first year of life are associated with the risk of childhood type 1 diabetes (T1D). According to the beta-cell stress hypothesis all factors that increase the need for, or the resistance to, insulin may be regarded as risk factors for T1D.

METHODS

Among 8921 children from the general population with questionnaire data from one parent at child's birth and at 1 year of age, 42 cases of T1D were identified up to 11-13 years of age. Additionally 15 cases with multiple diabetes-related autoantibodies were detected in a sub-sample of 2649 children.

RESULTS

Cox regression analyses showed no significant associations between serious life events (hazard ratio 0.7 for yes vs. no [95% CI 0.2-1.9], p=0.47), parenting stress (0.9 per scale score [0.5-1.7], p=0.79), or parental dissatisfaction (0.6 per scale score [0.3-1.2], p=0.13) during the first year of life and later diagnosis of T1D, after controlling for socioeconomic, demographic, and diabetes-related factors. Inclusion of children with multiple autoantibodies did not alter the results.

CONCLUSIONS

No association between psychological stress early in life and development of T1D could be confirmed.

Birthweight and the risk of childhood-onset type 1 diabetes: a meta-analysis of observational studies using individual patient data

AIMS/HYPOTHESIS

We investigated whether children who are heavier at birth have an increased risk of type 1 diabetes.

METHODS

Relevant studies published before February 2009 were identified from literature searches using MEDLINE, Web of Science and EMBASE. Authors of all studies containing relevant data were contacted and asked to provide individual patient data or conduct pre-specified analyses. Risk estimates of type 1 diabetes by category of birthweight were calculated for each study, before and after adjustment for potential confounders.Meta-analysis techniques were then used to derive combined ORs and investigate heterogeneity between studies.

RESULTS

Data were available for 29 predominantly European studies (five cohort, 24 case-control studies), including 12,807 cases of type 1 diabetes. Overall, studies consistently demonstrated that children with birthweight from 3.5 to 4 kg had an increased risk of diabetes of 6% (OR 1.06 [95% CI 1.01-1.11]; p=0.02) and children with birthweight over 4 kg had an increased risk of 10% (OR 1.10 [95% CI 1.04-1.19]; p=0.003), compared with children weighing 3.0 to 3.5 kg at birth. This corresponded to a linear increase in diabetes risk of 3% per 500 g increase in birthweight (OR 1.03 [95% CI 1.00-1.06]; p=0.03). Adjustments for potential confounders such as gestational age, maternal age, birth order, Caesarean section, breastfeeding and maternal diabetes had little effect on these findings.

CONCLUSIONS/INTERPRETATION

Children who are heavier at birth have a significant and consistent, but relatively small increase in risk of type 1 diabetes.

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

OBJECTIVE

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

RESEARCH DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Atopy, home environment and the risk of childhood-onset type 1 diabetes: a population-based case-control study

BACKGROUND

The marked increases in the incidence of type 1 diabetes in recent decades strongly suggest the role of environmental influences. These environmental influences remain largely unknown.

OBJECTIVE

To investigate atopy and home environment (such as children living at home, sharing a bedroom and house moves) as potential risk factors for type 1 diabetes.

SUBJECTS AND METHOD

In Northern Ireland, 175 children with type 1 diabetes and 4859 control children completed a questionnaire on atopy experience, family composition and home environment. Control children from two age groups (6-8 yr old and 13-14 yr old) were identified from randomly selected primary and secondary schools across Northern Ireland. Cases were identified from a population-based type 1 diabetes register.

RESULTS

There was little evidence of a difference in the proportion of participants with a history of atopy in the cases compared with controls. There was a significant reduction in the risk of diabetes in children who lived with more siblings {odds ratio (OR) = 0.58 [95% confidence interval (95% CI) 0.39-0.85] in children who lived with three or more siblings compared with one or none} and in children who moved house more often [OR = 0.59 (95% CI 0.40-0.88) in children who moved house twice or more compared with never].

CONCLUSION

The reduced risk of type 1 diabetes in children living with siblings, sharing a bedroom and moving house more often could reflect the protection afforded by exposure to infections in early life and consequently may provide support for the hygiene hypothesis.

Caesarean section is associated with an increased risk of childhood-onset type 1 diabetes mellitus: a meta-analysis of observational studies

AIMS/HYPOTHESIS

The aim of this study was to investigate the evidence of an increased risk of childhood-onset type 1 diabetes in children born by Caesarean section by systematically reviewing the published literature and performing a meta-analysis with adjustment for recognised confounders.

METHODS

After MEDLINE, Web of Science and EMBASE searches, crude ORs and 95% CIs for type 1 diabetes in children born by Caesarean section were calculated from the data reported in each study. Authors were contacted to facilitate adjustments for potential confounders, either by supplying raw data or calculating adjusted estimates. Meta-analysis techniques were then used to derive combined ORs and to investigate heterogeneity between studies.

RESULTS

Twenty studies were identified. Overall, there was a significant increase in the risk of type 1 diabetes in children born by Caesarean section (OR 1.23, 95% CI 1.15-1.32, p < 0.001). There was little evidence of heterogeneity between studies (p = 0.54). Seventeen authors provided raw data or adjusted estimates to facilitate adjustments for potential confounders. In these studies, there was evidence of an increase in diabetes risk with greater birthweight, shorter gestation and greater maternal age. The increased risk of type 1 diabetes after Caesarean section was little altered after adjustment for gestational age, birth weight, maternal age, birth order, breast-feeding and maternal diabetes (adjusted OR 1.19, 95% CI 1.04-1.36, p = 0.01).

CONCLUSIONS/INTERPRETATION

This analysis demonstrates a 20% increase in the risk of childhood-onset type 1 diabetes after Caesarean section delivery that cannot be explained by known confounders.

Psychological stress as a factor potentially contributing to the pathogenesis of Type 1 diabetes mellitus

Diabetes mellitus Type 1 (T1D) is an autoimmune disorder attributed to both genetic and environmental factors. The aim of this study was to identify certain stressful conditions potentially associated with the pathogenesis and/or expression of T1D. The study group included 107 children with diabetes (CD) and 153 controls of comparable age and gender distribution at diagnosis of T1D (10.73+/-3.62 yr vs 9.59 +/-3.42 yr, respectively). The parents of both groups completed a questionnaire on socioeconomic status and stressful life events or adverse situations at home and school.

RESULTS

Lower social class was more prevalent among the mothers of CD (p=0.002) in comparison with the controls. Stressful life events (parental death, divorce, parental job loss), problems at home (parental abuse, parental dispute) and at school (poor performance) were more frequently observed in the CD group than in the controls (parental death: p=0.05, job loss: p=0.05, parental abuse: p=0.002, quarrels between parents: p=0.05, and among siblings p=0.002, poor school performance: p=0.037). A stepwise logistic regression analysis indicated that lower maternal social class [odds ratio (OR): 3.86, 95% confidence interval (CI): 1.37,10.9], parental dispute or divorce (OR: 2.78, 95%CI: 0.97,7.95), body mass index (OR: 0.87, 95%CI: 0.78,0.97), increasing age (OR: 1.14, 95%CI: 1.02,1.27) were the factors potentially influencing the occurrence of T1D, while the 2-yr period prior to diabetes occurrence emerged as the most important one (OR: 2.49, 95%CI: 1.14,5.42).

CONCLUSION

Children with diabetes seem to experience certain stressful conditions with significantly increased frequency compared to controls, especially during the 2 yr preceding the diagnosis of T1D, with a higher clustering in those of lower social class. The resultant stress possibly contributes to the development of T1D in genetically susceptible individuals.

Early infant feeding and risk of type 1 diabetes mellitus-a nationwide population-based case-control study in pre-school children

BACKGROUND

The evidence on the role of environmental factors in the development of type 1 diabetes is conflicting. Reducing potential bias and the variety of exposures, we investigated the association between type 1 diabetes risk and nutritional and environmental exposures in pre-school children.

METHODS

This nationwide population-based case-control study included 760 cases under 5 years of age newly diagnosed with type 1 diabetes during 1992-1995. From the general population, 1,871 controls were randomly selected and individually matched on age ( +/- 1 year), sex, and residence. Information on infant diet, foetal, perinatal and socio-economic factors, and familial diabetes was obtained by a parent-administered questionnaire. Data were analysed by multiple conditional logistic regression.

RESULTS

Duration of breastfeeding and age at introduction of bottle-feeding were inversely associated with type 1 diabetes risk according to a dose-response relationship (trend test p < 0.05). Adjusted odd ratios (95% CI) for a long breastfeeding period and a late introduction of bottle-feeding (>or=5 month versus < 2 weeks) were 0.71 (0.54-0.93) and 0.80 (0.62-1.04), respectively. Familial type 1 diabetes, maternal age > 40 years, and low birth weight were found more frequently among diabetic than among control children. Current cow's milk consumption, higher social status, and a larger family were associated with a reduced diabetes risk. Up to one half of the diabetic cases in the population could be attributed to modifiable exposures.

CONCLUSIONS

Our findings indicate that infant feeding is associated with type 1 diabetes risk and that a considerable part of new type 1 diabetic cases is potentially preventable.

No association between routinely recorded infections in early life and subsequent risk of childhood-onset Type 1 diabetes: a matched case-control study using the UK General Practice Research Database

AIMS

To determine whether children with infections in early life (recorded routinely in general practice) have a reduced risk of Type 1 diabetes, as would be expected from the hygiene hypothesis.

METHODS

Children with Type 1 diabetes and up to 20 matched (on year of birth, sex and region) control subjects were selected from a cohort of children born in the UK at General Practice Research Database practices. For each child, the frequency of general practitioner consultations for infections and prescriptions for antibiotics in the first year of life were determined. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using conditional logistic regression.

RESULTS

The main analysis included 367 case and 4579 matched control subjects. There was no evidence of any reduction in the subsequent risk of Type 1 diabetes in children with at least one infection in the first year of life (OR = 1.03, 95%CI 0.79, 1.34) or in children prescribed antibiotics in the first year of life (OR = 1.03, 95%CI 0.82, 1.29). Further analyses also revealed little evidence of a difference in subsequent risk of Type 1 diabetes after different types of infection in the first year of life (including gastrointestinal, conjunctivitis, otitis media and upper and lower respiratory tract). Analyses of infections in the first 2 years of life reached similar conclusions.

CONCLUSIONS

This study provides no evidence of an association between infections in early life and subsequent risk of childhood-onset Type 1 diabetes and therefore does not support the hygiene hypothesis.

Worldwide childhood type 1 diabetes incidence--what can we learn from epidemiology?

Type 1 diabetes is the most common form of diabetes in most part of the world, although reliable data are still unavailable in several countries. Wide variations exist between the incidence rates of different populations, incidence is lowest in China and Venezuela (0.1 per 100,000 per year) and highest in Finland and Sardinia (37 per 100,000 per year). In most populations girls and boys are equally affected. In general, the incidence increases with age, the incidence peak is at puberty. After the pubertal years, the incidence rate significantly drops in young women, but remains relatively high in young adult males up to the age 29-35 years. Prospective national and large international registries (DIAMOND and EURODIAB) demonstrated an increasing trend in incidence in most regions of the world over the last few decades and increases seem to be the highest in the youngest age group. Analytical epidemiological studies have identified environmental risk factors operating early in life which might have contributed to the increasing trend in incidence. These include enteroviral infections in pregnant women, older maternal age (39-42 years), preeclampsia, cesarean section delivery, increased birthweight, early introduction of cow's milk proteins and an increased rate of postnatal growth (weight and height). Optimal vitamin D supplementation during early life has been shown to be protective. Some of these environmental risk factors such as viruses may initiate autoimmunity toward the beta cell, other exposures may put on overload on the already affected beta cell and thus accelerate the disease process.

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.

Stressful life events and psychological dysfunctions before the onset of type 1 diabetes mellitus

AIM

To test the hypothesis that stressful life events and psychological dysfunction increase the risk for development of type 1 diabetes mellitus (DM1).

METHOD

A case-control study comprising 105 children with DM1 and 210 controls matched by age +/- 1 year), sex and place of residence. Conditional univariate and multivariate logistic regressions were used to analyze the data.

RESULTS

After adjustment for possible confounders, the following factors were positively related to DM1: parents' job-related issues changed or lost job (odds ratio [OR] 11.5, 95% confidence interval [CI] 1.6-81.8); other severe life events--severe accident, hospitalization or death of close friend, quarrels between parents, war in republics of former Yugoslavia, near-drowning in a pool, falling down, unhurt participant of an accident (OR 68.5, 95% CI 13.5-349.0); other minor life events--conflicts with parents/teacher/neighbors, lost in town, physical attack, failure in competition, penalty, examination, death of pet, presence at lightning strike, thrown out of dwelling (OR 32.7, 95% CI 6.3-169.6); and learning problems (OR 17.5, 95% CI 4.3-71.6).

CONCLUSION

These results support the hypothesis that stressful life events and psychological dysfunctions are associated with DM1.

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.

Diabetes information systems: a rapidly emerging support for diabetes surveillance and care

BACKGROUND

With the rapid advances in information technology in the last decade, various diabetes information systems have evolved in different parts of the world. Availability of new technologies and information systems for monitoring and treating diabetes is critical to achieving recommended metabolic control, including glycosylated hemoglobin levels. The first step is to develop a registry, including a patient identifier that can link multiple data sources, which can then serve as a springboard to electronic mechanisms for practitioners to gain information on performance and results.

OBJECTIVE

The aim is to review the provisions for diabetes surveillance in different parts of the world. This is a systematic review of national and regional information systems for diabetes surveillance.

LITERATURE REVIEW

A comprehensive review was undertaken using Medline literature review, internet search using the Google search engine, and e-mail consultation with opinion leaders. TOPICS REVIEW: National/regional-level diabetes surveillance systems in Europe, the United States, Australia/New Zealand, and Asia have been reviewed. State-of-the-art diabetes information systems linking multiple data sources, with extensive audit and feedback capabilities, have also been looked at.

RESULTS

National/regional-level audit databases have been tabulated. Diabetes information systems linking multiple data sources have been described. Most of the developed countries have now implemented systems such as diabetes registers and audits for diabetes surveillance in at least some regions, if not nationally. Developing nations are beginning to recognize the need for chronic disease management.

CONCLUSIONS

With the advancements in information technology, the diabetes registers have the potential to rise beyond their traditional functions with dynamic data integration, decision support, and data access, as demonstrated by some diabetes information systems. With the rapid pace of development in electronic health records and health information systems, countries that are beginning to build their health information technology infrastructure could benefit from planning and funding along these lines.

Association between infectious diseases and type 1 diabetes: a case-crossover study

BACKGROUND

To investigate the role of infectious diseases in the development of type 1 diabetes, this study estimated the relative risks of type 1 diabetes immediately after infectious diseases.

RESEARCH DESIGN AND METHODS

A case-crossover design was employed. Information on infectious diseases during 407 d before the onset of type 1 diabetes was collected from medical records and parents' interviews for 260 patients in Chinese type 1 diabetes registry. The frequency of infectious diseases in 42 d before the onset of type 1 diabetes was compared with either the usual frequency of infectious diseases over the past year or the actual frequency of infectious diseases in a comparable 42-d control period.

RESULTS

Forty-eight (18%) patients were reported to have infectious diseases during this period based on medical records and interviews with parents. The relative risk of type 1 diabetes onset was markedly elevated to 10.1 (5.6, 17.9) immediately after infectious diseases, suggesting the role of infections as a precipitator. The relative risk decreased gradually before and after 42 d and was similar between male and female patients.

CONCLUSION

The results showed that infectious diseases are associated with a large and transient increase in the risk of type 1 diabetes during 42 d after the infection.

The Belgrade childhood diabetes study - comparison of children with type 1 diabetes with their siblings

A case-control study was conducted in Belgrade (about 320,000 inhabitants 0-16 years old) during the period 1994-97, comprising 68 diabetic children (cases) and 68 controls chosen from the siblings of the cases. Analysis using multivariable logistic regression analysis indicated the following independent risk factors for Type 1 diabetes: higher birth order, infections during the 6 months preceding the onset of the disease and stressful events. Out of individual stressful and psychological factors, 'other' stressful events (severe accident or hospitalisation or death of a close friend, conflict with a teacher, death of a pet, failure in competition, quarrel between parents, punishment, physical attack, war in republics of former Yugoslavia and near drowning in the pool) and learning problems were independent risk factor for Type 1 diabetes. The results obtained in this study of siblings supports the hypothesis that environmental factors play a role in the development of Type 1 diabetes.

A new model for understanding the role of environmental factors in the origins of chronic illness: a case study of type 1 diabetes mellitus

There is a need for a new pathophysiological model explaining and linking the role of numerous non-genetic factors believed to contribute to origins of many chronic physical diseases. This article presents a theoretical model for explaining the confusing and often contradictory findings regarding the role of environmental influences in type 1 diabetes, a disease that has been widely studied, for which clear diagnostic criteria exist, and for which development of effective prevention strategies represents significant challenges. The model is formulated from the large database of research regarding increasing understanding of the interaction between environmental factors, physiology, and autonomic regulatory function. Data is integrated from research in the fields of the experience-dependent maturation of the nervous system and the neurophysiology of traumatic stress to demonstrate how disruptions in early bonding and attachment, including adverse events such as traumatic stress, are capable of causing: (1) long-term imbalances in autonomic regulatory function and (2) relative dominance of sympathetic or parasympathetic activity. The proposed model of autonomic dysfunction suggests that ongoing mechanisms promoting high glucose in the context of decreasing insulin production in type 1 diabetes represent a state of relative sympathetic dominance influenced by environmental factors affecting autonomic, immune and endocrine systems during critical period programming. The model further identifies a link between the many seemingly unrelated non-genetic risk factors, and appears capable of explaining contradictions and enigmas in epidemiological and clinical studies regarding non-genetic origins of type 1 diabetes, including the role of stress, variation in age of onset, and duration of the preclinical phase.

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.

The belgrade childhood diabetes study: association of infections and vaccinations on diabetes in childhood

PURPOSE

The aim of this study was to investigate whether individual infections or combination of infections or vaccination affect the risk of developing diabetes in childhood.

METHODS

A case-control study was conducted in Belgrade during the period between 1994 and 1997. A total of 105 recent onset diabetics were compared with 210 controls chosen among children with skin disease (the first control group). Cases and controls were individually matched by age (+/-1 year), sex, and place of residence. Eighty-six diabetic children were also compared with their brothers/sisters (the second control group).

RESULTS

After adjustment for confounding variables, independent association with diabetes was found for infections during the 6 months preceding the onset of the disease, when cases were compared with both the first control group (OR=4.23, 95% CI, 1.95-9.17, p<0.001) and the second control group (OR=4.68, 95% CI, 2.09-10.47, p<0.001), and for regular vaccination when cases were compared with the first control group (OR=0.08, 95% CI, 0.01-0.50, p=0.03).

CONCLUSION

The results obtained support the hypotheses that infections play a role in the development of type 1 diabetes and that regular vaccination has a preventive effect.

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.

The Belgrade childhood diabetes study: prenatal and social associations for type 1 diabetes

The aim of this study was to investigate whether prenatal and social factors are associated with the development of type 1 diabetes. A case-control study was conducted in Belgrade during the period 1994-97. A total of 105 children </= 16 years old with recently onset of diabetes and 210 control children, individually matched by age (+/- 1 year), sex and place of residence, were included in the study. In the analysis using multivariable logistic regression, the following factors were significantly related to type 1 diabetes: poor socio-economic status (Odds ratio = 4.18, 95% confidence interval [2.01, 8.72]); higher education of father (1.53, [1.16, 2.03]); complications during pregnancy (3.39, [1.64, 7.00]); ultrasound scan during pregnancy (0.40, [0.20, 0.79]); gestational age > 41 weeks (11.11, [1.80, 68.52]); mother's consumption of foods containing nitrosamines during pregnancy (3.14, [1.68, 5.87]); and consumption of alcohol by father (4.54, [2.34, 8.79]).

Space-time clustering of childhood Type 1 diabetes in Devon and Cornwall, England

AIMS

Several studies on space-time clustering have been reported in childhood diabetes, but the findings are conflicting. The present study was undertaken to examine whether such clustering could be detected at either birth or the time of diagnosis in the far South-west of England.

METHODS

A cohort of 518 children aged 0-15 years and diagnosed with Type 1 diabetes from 1975 to 1996 contained in the population-based Cornwall and Plymouth Children's Diabetes Register (CPCDR) were included in the analyses. The case ascertainment for this register is estimated to be 94.4% complete. Mantel's modification of Knox's method was employed. A method based on K-function was also used, for the first time, to investigate the space-time clustering of diabetes.

RESULTS

Significant space-time clustering at diagnosis was found by the Knox's test in the following combinations of critical cut-off thresholds: 25, 35 and 50 km and 90, 270 and 360 days (all P < 0.05), with the highest significance found at 35 km and 360 days (P = 0.0011). K-function analysis also confirmed the overall clustering (P = 0.013).

CONCLUSIONS

There is strong evidence of space-time clustering in the onset of childhood Type 1 diabetes in Devon and Cornwall, England. These results lend some support to the hypothesis that viral infections and some unknown localized environmental factors play a role in the development of childhood Type 1 diabetes.

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.

The epidemiology of childhood-onset type 1 diabetes mellitus in Romania. ONROCAD Study Group. National Romanian Organisation for the Care of Diabetic Children and Adolescents

The ONROCAD Study group was established to provide descriptive epidemiological information on type 1 diabetes mellitus (DM) in Romania. Data on all new patients with type 1 DM with onset before age 15 years during the four-year period 1992-1995 in Romania were submitted from all members of the ONROCAD Study Group, representing all doctors and clinics that manage children with DM in Romania. Age- and sex-specific incidence rates were estimated, using available demographic data. A total of 706 new patients with type 1 DM and onset 0-14 years was registered. The overall completeness of ascertainment was estimated at 93.5%. For all Romania, the incidence of childhood-onset type 1 DM was estimated at 3.57/100,000/year. The incidence in the three regions was statistically significantly different (p = 0.002), with high rates in Transylvania and low rates in Muntenia. Girls had a significantly higher incidence than boys for each of the age groups 0-4, 5-9 and 10-14 years. Between these age groups, the incidence increased significantly with age. The incidence of childhood-onset type 1 DM is among the lowest recorded in Europe. Significant, but unexplained, geographical variation exists within Romania. Searches for factors to explain this heterogeneity may provide clues to the etiology of childhood-onset type 1 DM.

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.

IDDM and early exposure of infant to cow's milk and solid food

Associations studies were attempted between the type of feeding, duration, and time of starting of solid foods in infancy and the incidence of insulin-dependent diabetes mellitus (IDDM). The study subjects comprised 52 IDDM patients and 52 control subjects matched for sex, age, social status, country, geographical location and selected from pediatric departments of different hospitals in Tehran. Diabetic children (21 boys, 31 girls) were of the ages of 1.5 to 14 years. Information about the pattern of their feeding at the first two years of life were collected through questionnaires administered to the mothers. The questionnaire was designed to evaluate the duration of complete or partial breast-feeding and the age at which dietary products containing cow's milk were introduced into the diet. A large proportion of the diabetic children rather than the control children had been breast-fed, and the risk of IDDM among children who had not been breast-fed was below unity. No significant difference in the duration of breast-feeding was observed between diabetic and control group. Our data do not support the existence of a protective effect of breast-feeding on the risk of IDDM, nor do the data indicate that early exposure to cow's milk and dairy products has any influence on the development of IDDM.

Decreased prevalence of atopic diseases in children with diabetes. The EURODIAB Substudy 2 Study Group

OBJECTIVE

To test the hypothesis that atopic diseases in early life are associated with a reduced risk (protection) for the development of type 1 diabetes in childhood.

STUDY DESIGN

European centers (n = 8) with access to population-based type 1 diabetes registries (>90% degree of ascertainment) participated in a case control study focusing on early exposures and risk factors for type 1 diabetes. Altogether, data from 1028 members of a case group and 2744 members of a control group corresponding to 85.4% eligible members of the case group and 76.1% of the control group were analyzed. Information in this study was collected regarding atopic diseases (atopic eczema, allergic rhinoconjunctivitis, and asthma).

RESULTS

Atopic disease and asthma particularly are associated with significant reductions in risk of childhood type 1 diabetes. The risk reduction associated with asthma was observed reasonably consistently among the 8 study centers, which represent a wide range of diabetes incidence. Risk reductions associated with all 3 expressions of atopy were particularly marked in children whose type 1 diabetes was diagnosed in the 10- to 14-year age group.

CONCLUSION

These findings indicate that atopic conditions may be protective against the development of type 1 diabetes and are consistent with the immunologic concept of T(H)1 (type 1 diabetes) and T(H)2 (atopy) diseases being mutually exclusive.

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.

Increased frequency of IgM antibodies to cow's milk proteins in Hungarian children with newly diagnosed insulin-dependent diabetes mellitus

We investigated the association between serum antibodies to cow's milk proteins and insulin-dependent diabetes mellitus (IDDM) in Hungarian children. Forty-eight children 1.0-17.1 years of age with newly diagnosed IDDM and 74 control children 1.0-16.0 years of age were studied for serum IgG, IgA and IgM antibodies to cow's milk, beta-lactoglobulin, bovine serum albumin and ovalbumin by enzyme-linked immunosorbent assays. The specificity of IgM antibodies to beta-lactoglobulin and bovine serum albumin was controlled by Western blot. The levels of IgG and IgA antibodies to cow's milk proteins were similar in children with and without IDDM, with the exception of slightly increased levels of IgA antibodies to beta-lactoglobulin in diabetic children (P = 0.05). The levels of IgM antibodies to cow's milk were significantly higher in IDDM patients than in control children (P = 0.0002). Children with IDDM more often had IgM antibodies to beta-lactoglobulin (46.3% vs 18.8%; P = 0.002) and bovine serum albumin (87.8% vs 49.3%, P < 0.0001) than control children. Neither the levels of IgG or IgA antibodies to ovalbumin nor the frequency of IgM antibodies to ovalbumin differed between diabetic and control children.

CONCLUSION

In Hungarian children, clinical manifestation of IDDM is often associated with IgM antibody response to cow's milk protein and its fractions, beta-lactoglobulin and bovine serum albumin, indicating a loss of immunological tolerance to these proteins. IgG and IgA antibodies to cow's milk proteins, associated with an early introduction of cow's milk in diet, seem to play a minor role in the development of childhood IDDM in Hungary.