Rising incidence of type 1 diabetes in Hungarian children (1978-1987). Hungarian Childhood Diabetes Epidemiology Group

Exploring quality of care and social inequalities related to type 2 diabetes in Hungary: Nationwide representative survey

AIMS

The study aimed to launch a T2DM adult cohort that is representative of Hungary through a cross-sectional study, to produce the most important quality indicators for T2DM care, to describe social inequalities, and to estimate the absolute number of T2DM adult patients with uncontrolled HbA1c levels in Hungary.

METHODS

A representative sample of the Hungarian T2DM adults (N=1280) was selected in 2016. GPs collected data on socio-demographic status by questionnaire, and on history and laboratory parameters from medical records. The process and outcome indicators used in the international monitoring practice were calculated. The socio-economic status influence was determined by multivariate logistic regression models.

RESULTS

Target achievement was 61.66%, 53.48%, and 54.00% for HbA1c, LDL-C, and blood pressure, respectively, in the studied sample (N=1176). In Hungary, 294,534 patients have above target HbA1c value out of 495,801 T2DM adults. The education-dependent positive association with majority of process indicators was not reflected in HbA1c, LDL-C, and blood pressure target achievements. The risk of microvascular complications and requirement of insulin treatment were higher among less educated.

CONCLUSIONS

According to our observations, the education-independent target achievement for HbA1c and LDL-C is similar as, for blood pressure is less effective in Hungary than in Europe.

Climates on incidence of childhood type 1 diabetes mellitus in 72 countries

We are aimed to systematically assess the worldwide trend in incidence of childhood type 1 diabetes mellitus (CT1DM) from 1965 to 2012 and to discuss whether climate affect incidence of CT1DM. We searched the relevant literatures in detail to judge the effect of different climates on incidence of CT1DM. The climates included Mediterranean, monsoon, oceanic, continental, savanna, and rainforest. According to different climates, we further researched relevant factor such as sunshine durations and latitudes. The overall incidence of CT1DM in 72 countries was 11.43 (95% CI 10.31–12.55) per 100,000 children/yr. The incidence of CT1DM in Oceanic climate [10.56 (8.69–12.42)] is highest compared with other climates; the incidence in 40°–66°34′N/S [14.71 (12.30–17.29)] is higher than other latitude groups; the incidence in sunshine durations with 3–4 hours per day [15.17 (11.14–19.20)] is highest compared with other two groups; the incidence of CT1DM from 2000 to 2012 [19.58 (14.55–24.60)] is higher than other periods; all p < 0.01. Incidence of CT1DM was increasing from 1965 to 2012, but incidence in Oceanic climate is higher than other climates. Furthermore, it is higher in centers with higher latitude and lower sunshine durations. The climates might play a key role in inducing CT1DM.

Clinical and genetic characteristics of autoimmune polyglandular syndrome type 3 variant in the Japanese population

OBJECTIVE

Type 1 diabetes (T1D) is commonly associated with autoimmune thyroid disease (AITD), and the occurrence of both T1D and AITD in a patient is defined as autoimmune polyglandular syndrome type 3 variant (APS3v). We aimed to clarify the differences in the clinical and genetic characteristics of APS3v patients and T1D patients without AITD [T1D/AITD(-)] in the Japanese population.

DESIGN/PATIENTS

Our subjects were 54 APS3v patients and 143 T1D/AITD(-) patients who were consecutively diagnosed at Nagasaki University Hospital from 1983 to the present.

RESULTS

A remarkable female predominance, a slow and older age onset of T1D, and a higher prevalence of glutamic acid decarboxylase autoantibodies were observed in APS3v patients compared to T1D/AITD(-) patients. The older onset age of T1D in APS3v patients was associated with a higher proportion of slow-onset T1D. Among the two major susceptible human leukocyte antigen (HLA) class II haplotypes in Japanese T1D, DRB1*0405-DQB1*0401, but not DRB1*0901-DQB1*0303, was associated with APS3v patients. Furthermore, DRB1*0803-DQB1*0601 was not protective in patients with APS3v. The frequencies of the GG genotype in +49G>A and +6230G>A polymorphism in the CTLA4 gene were significantly higher in T1D/AITD(-) patients, but not in APS3v patients, compared to control subjects.

CONCLUSIONS

In conclusion, we found notable differences in the clinical and genetic characteristics of APS3v patients and T1D/AITD(-) patients in the Japanese population, and the differences in the clinical characteristics between the two groups may reflect distinct genetic backgrounds including the HLA DRB1-DQB1 haplotypes and CTLA4 gene polymorphisms.

Twenty-one years of prospective incidence of childhood type 1 diabetes in Hungary--the rising trend continues (or peaks and highlands?)

The aim of this study was to examine secular trends in the incidence of type 1 diabetes in children aged 0-14 yr in Hungary over the period 1989-2009. Newly diagnosed children with type 1 diabetes aged 0-14 yr in Hungary were prospectively registered from 1989 to 2009. Primary ascertainment of cases was by prospective registration using hospital notifications. Case ascertainment was over 96% complete using the capture-recapture method. Standardized incidence rates were calculated and secular trends estimated using Poisson regression analysis. In Hungary during 1989-2009 a total number of 3432 children were identified, giving a standardized incidence rate of 12.5 [95% confidence interval (CI) 12.1-12.9] per 100,000 person yr. The overall incidence rate has doubled from 7.7 (95% CI 6.4-9.15) per 100,000 per yr in 1989 to 18.2 (95% CI 15.7-20.9) per 100,000 per yr in 2009. A significant linear trend in incidence (p < 0.001) has been observed over time, with a mean annual increase of 4.4%. The increase in incidence was present in both genders and in all age groups, with the largest relative increase in the youngest age group (6.2%; p < 0.001). The incidence of type 1 diabetes in Hungarian children continues to increase, with the highest rate in the very young. Although it seems that transient periods of stabilization followed by increases in incidence are apparent, the long-term trend continues to be steadily upward. Incidence of childhood type 1 diabetes is a dynamic process, probably reflecting the changes of the environmental exposures and continued registration is necessary to recognize these trends.

Prediction and prevention of type 1 diabetes mellitus: initial results and recent prospects

Epidemiological studies indicate that the incidence and prevalence of type 1 diabetes mellitus is rising worldwide. The increase in incidence has been most prominent in the youngest age group of childhood. Prediction of type 1a autoimmune diabetes can be established by a positive family history or by genetic, immunological or metabolic markers. Prevention of type 1 diabetes can be implemented at three different levels of pathogenesis: primary prevention in individuals without any sign of beta-cell damage, secondary prevention in individuals with signs of beta-cell destruction and tertiary prevention in patients with newly diagnosed type 1 diabetes. In the recent years our knowledge of the disease pathogenesis has grown quickly and worldwide several new prevention trials have been started. Probably immune intervention of type 1 diabetes will prove to be the most effective. Orv. Hetil., 2011, 152, 1916–1921.

“Always up or peaks and highlands?” Incidence of childhood type 1 diabetes in Hungary (1989–2009)

Aim of this study was to examine secular trends in the incidence of type 1 diabetes in children aged 0–14 years in Hungary over the period 1989–2009. Methods: Newly diagnosed children with type 1 diabetes aged 0–14 years in Hungary were prospectively registered from 1989 to 2009. Standardized incidence rates were calculated and secular trends were estimated using Poisson regression analysis. Results: Between 1989 and 2009 a total number of 3432 children were identified, giving a standardized incidence rate of 12.5 (95%CI 12.1–12.9) per 100 000 person/year. The overall incidence rate has doubled from 7.7 (95%CI 6.4–9.15) per 100 000 per year in 1989 to 18.2 (95%CI 15.7–20.9) per 100 000 per year in 2009. A significant linear trend in incidence (p<0.001) has been observed over time, with a mean annual increase of 4.4%. The increase in incidence was present in both genders and in all age groups, with the largest relative increase in the youngest age group (6.2%; p<0.001). Conclusion: The incidence of type 1 diabetes in Hungarian children continues to increase, with the highest rate in the very young. Orv. Hetil., 2011, 152, 1692–1697.

Prevalence of diabetes in a large, nationally representative population sample in Hungary

We examined the prevalence of diabetes in a large, Hungarian, nationally representative adult population sample. The overall prevalence of diabetes was 6.2% (95% CI: 5.7-6.6). Increasing age and body mass index (BMI), male gender, physical inactivity, lower self-reported financial status, hypertension and non-smoking were independently associated with diabetes.

An update on the etiology and epidemiology of diabetes mellitus

Diabetes mellitus is one of the most common endocrine disorders affecting almost 6% of the world's population. The number of diabetic patients will reach 300 million in 2025 (International Diabetes Federation, 2001). More than 97% of these patients will have type II diabetes. The projected increase in the number of diabetic patients will strain the capabilities of healthcare providers the world over. Thus it is of paramount importance to revisit the causes and epidemiology of diabetes mellitus. Diabetes mellitus is caused by both environmental and genetic factors. The environmental factors that may lead to the development of diabetes mellitus include physical inactivity, drugs and toxic agents, obesity, viral infection, and location. While type I diabetes is not a genetically predestined disease, an increased susceptibility can be inherited. Genetic susceptibility plays a crucial role in the etiology and manifestation of type II diabetes, with concordance in monozygotic twins approaching 100%. Genetic factors may have to be modified by environmental factors for diabetes mellitus to become overt. An individual with a susceptible gene may become diabetic if environmental factors modify the expression of these genes. Since there is an increase in the trend at which diabetes prevail, it is evident that environmental factors are playing a more increasing role in the cause of diabetes mellitus. The incidence of type I diabetes ranged from 1.9 to 7.0/100,000/yr in Africa, 0.13 to 10/100,000/yr in Asia, approximately 4.4/100,000/yr in Australasia, 3.4 to 36/100,000/yr in Europe, 2.62 to 20.18/100,000/yr in the Middle East, 7.61 to 25.7/100,000/yr in North America, and 1.27 to 18/100,000/yr in South America. The epidemiology of type II diabetes is equally bleak. The prevalence of type II diabetes ranged from 0.3 to 17.9% in Africa, 1.2 to 14.6% in Asia, 0.7 to 11.6% in Europe, 4.6 to 40% in the Middle East, 6.69 to 28.2% in North America, and 2.01 to 17.4% in South America.

An increasing trend in the incidence of type 1 diabetes mellitus in children aged 0-14 years in Romania--ten years (1988-1997) EURODIAB study experience

AIM

To assess the incidence of type 1 diabetes mellitus (DM1) in Romanian children aged 0-14 years using EURODIAB Study methodology.

METHODS

Data were collected for a 10-year interval (1988-1997) for the whole country, using the capture-recapture method.

RESULTS

We registered 1,418 newly diagnosed patients. The mean total incidence rate was 3.051/100,000/year. There was a wide geographic variation (6.71-fold) between the highest and the lowest incidence rates in different districts. We noticed a progressive increase of age-specific incidence rates from 1.43/100,000/year for the 0-4 year age subgroup to 4.37/100,000/year (10-14 years). The annual mean incidence rate rose from 1.91/100,000/year (1988) to 3.94/100,000/year (1996).

CONCLUSIONS

Romania is one of the European countries with the lowest incidence rates (3.051/100,000/year) for DM1 in children. There was an evident increasing trend of DM1 incidence in children between 1988 and 1997, with an annual increase of 7.57%.

Dynamic changes in the trends in incidence of type 1 diabetes in children in Hungary (1978-98)

OBJECTIVE

To determine the recent trends in incidence, to analyze the age and geographic distribution, as well as the seasonal pattern of type 1 diabetes in Hungarian children aged 0-14 yr for the period from 1978 to 1998.

METHODS

Primary ascertainment of cases was by retrospective (1978-88) and by prospective (1989-98) registration using hospital notifications. The level of ascertainment was estimated by the capture-recapture method. The temporal trend was estimated by fitting Poisson regression models to the yearly incidence data. Roger's test was used to investigate possible seasonal variation in time of diagnosis. Heterogeneity between geographic areas was assessed by Poisson regression.

RESULTS

A total of 2616 patients (1214 in the first 11 yr, 1402 in the remaining 10 yr) were identified; the male:female ratio was 0.93. The overall standardized incidence rate was 7.87 (95% CI = 7.57-8.18) per 100,000 person-yr, the lowest in the youngest (0-4 yr) and highest in the oldest (10-14 yr) age group. There was an increasing trend in incidence with a largest relative annual increase in the youngest age group. Seasonal and regional variations in incidence were also observed.

CONCLUSION

Our 21-yr study shows dynamic changes in incidence of childhood type 1 diabetes in Hungary, probably reflecting changes in the environment.

Interplay between heredity and environment in the recent explosion of type 1 childhood diabetes mellitus

The fast increase in the incidence of childhood type 1 diabetes mellitus (T1DM) that cannot be explained by changes in the genetic susceptibility, led us to look for environmental causes. To test the hypothesis that the initiation of the autoimmune process of childhood T1DM in genetically susceptible subjects begins in the perinatal period by a viral infection, we studied the seasonal variations in the month of birth of several cohorts of patients compared to the general population. Population groups with high or low T1DM incidence were analyzed separately by t-test and the Cosinor methods. In areas with populations with a high incidence (Israeli Jews, Sicily, Sardinia, Slovenia, Germany) we found that the children (in Sicily also young adults) who subsequently developed T1DM, have a higher incidence of births in the summer months than in other seasons of the year, a mirror image of the seasonality of the clinical onset of disease. This pattern differed significantly from the seasonality of the total live births in the same populations. In populations with a low T1DM incidence, (China, Japan and Cuba) no seasonality of month of birth was found. Similar findings have been reported, from five counties in the U.K. and the Netherlands. It is hypothesized that mothers who become pregnant during the period of yearly viral epidemics transmit to the fetus, either a virus or antiviral antibodies, which determine whether an autoimmune process against the pancreatic beta is initiated or whether the fetus is protected against that process.

Incidence, prevalence, and mortality of insulin-dependent (type 1) diabetes mellitus in Lithuanian children during 1983-98

AIMS/HYPOTHESIS

Our purpose is to analyze interrelations of the incidence, prevalence and mortality of childhood-onset insulin-dependent diabetes mellitus (type 1) in Lithuania.

METHODS

Incidence and prevalence rates were based on the national type 1 diabetes register during 1983-98. The cohort study was performed to evaluate the standardized mortality ratios.

RESULTS

The average incidence of type 1 diabetes during the 16-yr study period was 7.36 per 100,000/yr. For both males and females the highest incidence of type 1 diabetes was recorded in the 10-14 yr age group. The regression-based linear trends of the increase in incidence in various age groups and the annual percentage change for both genders was 2.05 (p = 0.0039) and the greatest regression slope is observed for both genders in the 10-14 yr age group. Regression-based linear trends in type 1 diabetes prevalence indicate an even growth in all age groups (3.47; p = 0.001), although the annual percentage change is most prominent in the 5-9 yr age group for girls (4.95%/yr) and in the 10-14 yr age group for boys (4.06%/yr). The standardized mortality ratio of all-cause mortality in people with diabetes is higher than in the common population 7.71 (p < 0.0001). The standard mortality ratio for all causes increases with longer diabetes duration.

CONCLUSION/INTERPRETATION

The significant increasing trend of incidence and prevalence during 1983-98 is observed. The annual percentage change is similar. The young patients with type 1 diabetes have a higher mortality risk.

Seasonality of birth in children (0-14 years) with type 1 diabetes mellitus in Slovenia

The aim of this study was to find out whether there is seasonality of month of birth of children with diabetes in Slovenia and if so whether it differs from that of the general population. A cohort of 849 children and adolescents (0-14 years) with type 1 diabetes mellitus born between 1956 and 1998 were included in the study. Monthly and seasonal patterns of birth of the patients with diabetes were compared with the pattern of normal live births (n = 1,345,921) and the pattern of disease onset. Statistical analysis was made using Student's t-test to compare the means between the four seasons of the year, and single cosinor analysis for a period of 12 months. The children and adolescents with diabetes had a statistically significant different seasonality of month of birth compared to that of the general population, and an opposite pattern from the seasonality of month of onset of disease. The observations made are in accordance with observations made recently in other countries and support the hypothesis that a virus infection transmitted by the mother to the fetus during the annual viral epidemic induces the autoimmune process in the pancreatic beta-cells in genetically susceptible individuals who will subsequently develop clinical diabetes during childhood.

Epidemiology and estimated population burden of selected autoimmune diseases in the United States

Autoimmune diseases cause significant and chronic morbidity and disability. The actual number of persons in the United States that are affected by autoimmune diseases and the resultant magnitude of their impact on the public's health are limited to a few specific diseases. In order to understand the clinical, public health and economic importance of these diseases it is necessary to have estimates of incidence and prevalence rates in the population. In this analysis, we estimate the number of persons affected by 24 autoimmune diseases in the United States by applying mean weighted prevalence and incidence rates obtained from published articles to U. S. Census data. The study was restricted to 24 autoimmune predefined diseases for which there was direct or indirect evidence for autoimmune pathogenesis. Subsequently, we used computerized search software and ancestry searching (bibliographies) to conduct a comprehensive search of articles published from 1965 to the present. Eligible studies included those which adhered to standard disease definitions and which included population-based estimates of incidence or prevalence rates. Mean weighted incidence and prevalence rates were calculated from eligible published studies with greater weight proportionately given to larger studies. The mean rates were then applied to the U.S. Census population figures to estimate the number of persons currently afflicted with each disease and the number of new cases occurring each year in the United States. Only U.S. and European studies were used to estimate prevalence and incidence rates when there were at least six eligible studies available for a disease. When there were fewer than six studies, all available studies were included, regardless of country of origin. The number of eligible incidence and prevalence studies found in the literature varied considerably between the 24 autoimmune diseases selected. The largest number of eligible prevalence studies were conducted on multiple sclerosis (MS), rheumatoid arthritis, and systemic lupus erythematosus (SLE) (>/=23), followed by insulin-dependent diabetes (IDDM), myasthenia gravis, primary biliary cirrhosis, and scleroderma (>/=7). There were only one to four eligible studies done on 11 other diseases, and no prevalence studies on 6 diseases. Incidence studies were less frequent but the largest number of studies were conducted on IDDM (n = 37) and MS (n = 28), followed by Graves' disease/hyperthyroidism, glomerulonephritis, primary biliary cirrhosis, rheumatic fever, rheumatoid arthritis, scleroderma, and SLE (>/=9). On the other 11 diseases, there were one to six eligible studies, and no studies on 5 diseases. There were no eligible incidence or prevalence studies on Goodpasture's syndrome, idiopathic thrombocytopenia purpura, or relapsing polychondritis. Overall we estimate that 8,511,845 persons in the United States or approximately 1 in 31 Americans are currently afflicted with one of these autoimmune diseases. The diseases with the highest prevalence rates were Graves'/hyperthyroidism, IDDM, pernicious anemia, rheumatoid arthritis, thyroiditis, and vitiligo, comprising an estimated 7,939, 280 people or 93% of the total number estimated. Glomerulonephritis, MS, and SLE added an estimated 323,232 people. The prevalence of the other diseases reviewed were rare, less than 5.14/100,000. Most diseases were more common in women. From the incidence data we estimate that 237,203 Americans will develop an autoimmune disease in 1996 and that approximately 1,186,015 new cases of these autoimmune diseases occur in the United States every 5 years. Women were at 2.7 times greater risk than men to acquire an autoimmune disease. After reviewing the medical literature for incidence and prevalence rates of 24 autoimmune diseases, we conclude that many autoimmune diseases are infrequently studied by epidemiologists. As a result the total burden of disease may be an underestimate. (ABSTRACT TRUNCATED)

Rising incidence of type 1 diabetes in Scottish children, 1984-93. The Scottish Study Group for the Care of Young Diabetics

OBJECTIVES

To calculate the incidence of type 1 diabetes in Scottish children aged less than 15 years between 1984 and 1993; to examine changes in incidence; and to calculate the prevalence of diabetes at the end of this period.

DESIGN

Three data sources were used to construct the Scottish Study Group for the Care of Young Diabetics register: active reporting of all new cases; reports from the Scottish Morbidity Register 1; and local registers.

SUBJECTS

All children resident in Scotland diagnosed with primary insulin dependent diabetes mellitus when less than 15 years of age between 1984 and 1993.

MAIN OUTCOME MEASURES

Annual incidence and prevalence rate for Scotland; time trend in incidence over the 10 years; differences in incidence between the three different age groups; and completeness of the register.

RESULTS

The average annual incidence for Scotland was 23.9/100,000 children. The prevalence rate was 1.5/1000 in 1993. A total of 2326 cases was identified from the three sources. Capture-recapture analysis suggests a case ascertainment of 98.6%. The annual incidence rates increased at a rate of 2% each year (rate ratio = 1.02, 95% confidence interval (CI) 1.01 to 1.03). The incidence was higher in boys than girls (rate ratio = 1.08, 95% CI 1.00 to 1.18), and the incidence rates increased with age: 15.3/100,000/year for age 0-4 years, 24.4/ 100,000/year for age 5-9 years, and 31.9/ 100,000/year for age 10-14 years.

CONCLUSIONS

The incidence of type 1 diabetes in Scotland is increasing and the prevalence is relatively high. These findings have important implications for health service resource allocation. The Scottish Study Group for the Care of Young Diabetics' register provides a base for monitoring and research.

Long-term patterns in seasonality of insulin-dependent diabetes mellitus diagnosis in Austrian children

The analysis of the seasonal pattern of incidence of childhood insulin-dependent diabetes mellitus in Austria was carried out among cases where the child was under the age of 15 when diagnosed between 1979 and 1993. The cases are registered in the nationwide population-based Austrian insulin-dependent diabetes mellitus registry. Seasonal variation was compared between boys and girls and between three 5-year age groups. We also tested whether the seasonal pattern changed over the 15-year observation period. We found a significant seasonal variation among boys aged 10-14 and girls aged 5-14, while in the 0-4 years age group no seasonal pattern could be demonstrated. Two peaks in incidence were identified during a calendar year (February-March and September-October) for girls aged 5-14. For boys aged 10-14, a yearly cycle was found with a peak in January and October. An extension of the Poisson regression model for testing seasonality by Jones et al. was developed to allow for estimation of a time-dependent amplitude of the seasonal component. The annual incidence rate increased by 36% during the observation period, but no significant change in seasonal pattern could be demonstrated.

Incidence of IDDM during 1988-1992 in Zagreb, Croatia

The objective of this study was to determine the incidence of insulin-dependent diabetes mellitus (IDDM) in the population of Zagreb, Croatia, during 1988-1992. A centralized diabetes registry was the primary source of data, while secondary sources were used to assess ascertainment. A total of 282 new cases of IDDM were diagnosed in the study period, the primary and secondary sources identifying annually 93-100% of the cases. The annual incidence rate ranged from 5.6 per 100,000 to 6.6 per 100,000. Early fatality in persons older than 50 years was the major cause of underascertainment. The incidence peaked in the 10-14 years age group (12.4 per 100,000), and remained stable after age 24 years. Males had a significantly higher incidence in the 5-9 and 24-44 years age groups. In the 45-54 years age group, females had a significantly higher incidence. No seasonality was observed. Despite the war conditions in Croatia, the low overall IDDM incidence rates did not change significantly during the study period.

Insulin dependent diabetes in children under 5: incidence and ascertainment validation for 1992

OBJECTIVE

To establish the incidence of insulin dependent diabetes diagnosed in children under 5 years of age in the British Isles during 1992, comparing the national and regional results with those of our 1988 national study, and estimating the 1992 study's level of case ascertainment.

DESIGN

Active monthly reporting of cases by consultant paediatricians through the framework of the British Paediatric Surveillance Unit, with additional reports from specialist diabetes nurses and regional health authorities.

SUBJECTS

All children diagnosed under the age of 5 years with primary insulin dependent diabetes from 1 January to 31 December 1992 (inclusive) and resident in the British Isles at diagnosis.

RESULTS

387 children (208 boys and 179 girls) were confirmed to have insulin dependent diabetes, giving a national incidence of 9.3/100,000/year. This is similar to the 9.9/100,000/year found in 1988. Three sample capture-recapture analysis, which could only be applied across the 12 (out of 18) regions supplying regional information to the study, suggested ascertainment rates of 78% for the British Paediatric Surveillance Unit, 67% for specialist nurses, 69% for regional health authorities, and 99% for the aggregated registry.

CONCLUSIONS

The national incidence of diabetes in the under 5s in the British Isles did not differ between 1988 and 1992. Nearly complete (99%) ascertainment of cases was possible only for regions for which three data sources were available. Capture-recapture analysis highlighted both the need for more than one data source and for each data source to be complete for the whole study area.

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

Using the prospective Hungarian childhood diabetes register, a nationwide case-control study was carried out to investigate the possible role of various non-genetic factors as risk determinants for type 1 diabetes in childhood. A questionnaire (covering family characteristics, social status, fetal and perinatal events, breast-feeding habits, infectious diseases and stressful life events) was sent by mail to all incident diabetic children in 1990 (n = 163) and to two referent children (for each diabetic child), matched for age, sex and county. Diabetic children had a tendency to have mothers > 35 years of age (odds ratio (OR) = 3.52; 95% confidence intervals (CI) 0.74-16.79), a lower proportion of their mothers had higher education (OR = 1.69; 95% CI 0.95-3.0) and these children tended to move home more frequently (OR = 1.99; 95% CI 0.97-4.1). Although the duration of exclusive breast feeding was similar in both groups, the proportion of diabetic children who received no breast milk tended to be higher (OR = 1.76; 95% CI 0.91-3.4). A higher proportion of diabetic children reported non-specific infections (OR = 2.94; 95% CI 1.19-7.21) and the number of stressful life events was higher in diabetic children aged 10-14 years (OR = 3.9; 95% CI 1.14-13.27). As the risk determinants for childhood insulin-dependent diabetes mellitus identified in our low-risk population appear to be similar to those detected in the genetically different, high-risk Swedish population, our study strongly supports an etiological role for these non-genetic risk factors in IDDM.

A nationwide population-based study of the familial aggregation of type 1 (insulin-dependent) diabetes mellitus in Denmark. Danish Study Group of Diabetes in Childhood

The objective of the present study was to assess the prevalence of familial aggregation of Type 1 (insulin-dependent) diabetes mellitus among Danish families with a diabetic child aged 20 years or less and to compare epidemiological data for familial and sporadic cases. We attempted to identify all patients with Type 1 diabetes aged 0-19 years in Denmark treated at paediatric departments or at departments of internal medicine. This comprises more than 98% of all patients with Type 1 diabetes in this age group. Patients were identified through the local diabetic out-patient registry and asked to complete a questionnaire regarding data on diabetes onset and family history. Of 1574 probands 1419 agreed to participate (90.2%). Additional cases of Type 1 diabetes were found in 171 families (12.8%). Of these 115 were parent-offspring affected families, and in 56 families at least two siblings had Type 1 diabetes and healthy parents. Significant correlation in age at onset of Type 1 diabetes in concordant siblings was observed (r = 0.5, p = 0.0004). Significantly more probands had an affected father with Type 1 diabetes than a mother affected (p < 0.0001). Heterogeneity in epidemiological characteristics was observed between familial and sporadic cases, i.e. familial index cases were younger at onset of the disease, their parents were younger at birth of the index case, and there was no difference in gender of familial cases in contrast to sporadic cases where significantly more males were found. Over a 4-year period (1986-1989) an increasing trend in incidence was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of childhood-onset insulin-dependent diabetes mellitus: the EURODIAB ACE Study

EURODIAB ACE is a collaborative European study that was set up to assess incidence of childhood insulin-dependent diabetes mellitus (IDDM) in Europe, test the proposal of a south-north gradient, and to gather information to determine the causes and pathogenesis of the disease. Here, the basic epidemiological results are reported. Newly diagnosed cases of IDDM in children aged up to 15 years were identified prospectively in twenty-four geographically well-defined study regions in Europe and Israel (a total of 16.8 million children) during 1989 and 1990. 3060 cases were identified with estimated ascertainment rates exceeding 90% in all study regions. Age-standardised and sex-standardised incidence rates varied widely, ranging from 4.6 (northern Greece) to 42.9 (two regions in Finland) cases per 100,000 per year. Rates in southern Europe were generally higher than previously assumed, and there was an unexpectedly high incidence in Sardinia, which had the second highest rate (30.2 cases per 100,000 per year) recorded in Europe. Eastern European regions had generally low rates. The collaborative network now established provides a framework for further studies to examine the complex interaction between genetic and environmental factors in the cause and pathogenesis of IDDM.

Increasing incidence of early onset type 1 (insulin-dependent) diabetes mellitus: a study of Danish male birth cohorts

To provide information of the incidence trends of Type 1 (insulin-dependent) diabetes mellitus we performed a cohort study of a series of Danish male birth cohorts. All male livebirths in Denmark between 1 January 1949 and 31 December 1964, were investigated regarding the development of Type 1 diabetes during the first 20 years of life using the files of the Danish Conscript Board, supplemented by a search in the Danish National Registry of Deaths. Diagnosis was verified and clinical information obtained from medical records. The material is estimated to be more than 95% complete. A total of 1705 diabetic subjects were identified of whom 23 were not representative of idiopathic Type 1 diabetes. The cumulative rate of Type 1 diabetes development during the first 20 years of life increased from 2.37 to 2.90 per 1000 for the first eight and last eight birth cohorts, respectively. A log-linear analysis of the incidence revealed significantly increasing incidence rates, independent of age effects, with a maximum in the late 1970's. About 75% of the cases presented short duration of symptoms prior to diagnosis, and only very few cases were diagnosed incidentally. Cases were diagnosed relatively less frequently during summer months than during winter months.

The changing face of the epidemiology of insulin-dependent diabetes mellitus (IDDM): research designs and models of disease causation

Epidemiology can be broadly defined as the study of the cause and distribution of diseases in human populations. This review is concerned with the role of epidemiology in elucidating the cause of insulin-dependent diabetes mellitus (IDDM). Methodological aspects of epidemiologic studies are discussed including study designs and their limitations. Markers of genetic susceptibility to IDDM are examined in terms of their potential value for selecting high risk individuals for prospective follow-up studies of IDDM etiology. Models of disease causation pertinent to IDDM are presented with a primary focus on the recently developed epigenesis theory. Finally, a framework is provided that integrates approaches of infectious disease, chronic disease and genetic epidemiology, to link epidemiologic data with information from other disciplines, such as genetics, microbiology or immunology.

The incidence of type 1 (insulin-dependent) diabetes mellitus 15-29 years in Norway 1978-1982

All new cases of Type 1 (insulin-dependent) diabetes mellitus in the 15-29 year age group during the five-year period 1978-1982 were registered using a retrospective technique on a nation-wide basis. A total of 784 newly diagnosed cases were detected, from an average population of 926,192. The degree of ascertainment was almost 90%. The mean yearly incidence for the five-year period was 17.0 per 100,000. The observed incidence is doubled compared to the incidence found in the city of Oslo during the years 1956-1964 (8.8 per 100,000). The male incidence exceeded the female incidence by 12% (p less than 0.05). There was a marked geographic variation in incidence, with a higher incidence in the three southern health regions compared to the two northern, 18.3 vs 13.9 per 100,000 (p less than 0.01). There was a significant seasonal trend in the incidence data (p less than 0.025) with the highest number of new cases detected in the months of January and September and the lowest number in July. In conclusion, the study suggests a two-fold increase of incidence of diabetes mellitus in the age group 15-29 years during the last 2-3 decades and a geographic variation in incidence within the country, pointing to the operation of environmental pathogenic factors.

Incidence of insulin dependent diabetes in children aged under 15 years in the British Isles during 1988

OBJECTIVE

To ascertain the annual incidence rate of insulin dependent diabetes diagnosed in children under the age of 15 years in the British Isles during 1988, and to compare the results with an earlier study carried out in 1973-4.

DESIGN

Active monthly reporting of cases by consultant paediatricians, with additional input from diabetologists and all specialist diabetes nurses and health visitors.

SETTING

British Isles (England, Wales, Scotland, Northern Ireland, Republic of Ireland) with a total population at risk of 11,819,000 children.

PATIENTS

All children diagnosed under the age of 15 years with primary insulin dependent diabetes from 1 January to 31 December 1988 and resident in the British Isles at diagnosis.

MAIN OUTCOME MEASURES

National incidence rate of insulin dependent diabetes; differences in incidence rates between regions and between three age groups: 4 and under, 5-9, and 10-14 year olds.

RESULTS

1600 children (837 boys and 763 girls) had a confirmed diagnosis of insulin dependent diabetes, giving a national incidence rate of 13.5/100,000/year (95% confidence interval 12.9 to 14.2/100,000/year). This was considerably higher than the incidence rate of 7.7/100,000/year in children under the age of 16 years reported in the British Diabetic Association's study of 1973-4. The age-sex adjusted rates varied between regions, ranging from 6.8/100,000/year (Republic of Ireland) to 19.8/100,000/year (Scotland). There were considerable differences in the numbers of cases diagnosed each month, with the 10-14 year age group showing the most seasonal variation. A quarter of the children (404/1600) were under 5 years old. Case ascertainment was estimated as 90%.

CONCLUSIONS

Insulin dependent diabetes in the British Isles does not seem to occur uniformly over time or geographical area. Even allowing for differences in ascertainment between the 1973-4 and 1988 studies, there seems to have been an increase in the incidence rate of insulin dependent diabetes in children under the age of 15 years during the 15 year time period. If diabetes is becoming more common in this age group, possibly by developing earlier in susceptible children, this would be a matter of considerable public health concern.