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

Cohort Profile: The Danish Conscription Database(DCD): A cohort of 728,160 men born from 1939 through 1959

The Danish Conscription Database (DCD) was established to enable studies of the influence of early physical and mental exposures on adverse health and social outcomes from a life-course perspective. In Denmark, all young men are requested to appear before the conscription board when they turn 18 years, to be assessed for military service. The DCD was established by digitizing information from conscription board register cards on the height, weight, educational level, intelligence test score and examination details of Danish conscripts. The DCD contains information on 728,160 men born from 1939 through 1959 and examined by the conscription board from 1957 through 1984. The unique Danish personal identification number of each individual conscript has been traced, and this allows linkage of the DCD to all Danish health and socioeconomic registers. More than 130,000 deaths have been identified in a recent linkage to the Danish Register of Cause of Death. We encourage collaboration, and interested researchers should contact: danishconscriptiondatabase.glostrup-hospital@regionh.dk.

The perils of high carbohydrate drinks in the undiagnosed diabetic patient

Diabetes mellitus is increasing in its incidence and prevalence. Reduction in refined carbohydrate (sugar) intake is an important part of nutritional advice to patients with known diabetes. Sugar is available in a variety of confectionary products. It is also available in especially packaged 'convenience foods' as high energy drinks. Among people without diabetes, such food can have its own health risks. A significant group of patients with diabetes remain undiagnosed. This group are at especially high risk from all the negative metabolic effects of high sugar intake available as high calorie drinks. The authors report two patients without previously known diabetes who presented similarly with marked hyperglycaemic states, leading to severe metabolic disturbances. Both were obese, had common precipitating factors and consumed large quantities of sugary soft drinks ('lucozade'). Both patients recovered well. They were followed up for over 7 years. One is not diabetic and the second is diabetic requiring a small dose of metformin.

Long-term trends in the incidence of type 1 diabetes in Denmark: the seasonal variation changes over time

There is a worldwide increase of type 1 diabetes mellitus (T1DM). In 1996, the Danish population-based registry was initiated including all newly diagnosed children aged 0-15 yr. This is the report of incidence and seasonal variation for the first 10 yr of the registry. The data was analyzed using Poisson's regression analysis. A total of 2166 children with diabetes were diagnosed before the age of 15 yr between 1996 and 2005. In this period, the annual increase in childhood T1DM was 3.43% (95% confidence interval: 1.91-4.97), which was unaffected by age and gender. Seasonal variation in incidence rates varied by year but not by age and gender. In conclusion, there is a steep increase in incidence of childhood T1DM in Denmark; the increase is comparable with the increase seen in other European countries. There is a significant seasonal variation that changes on a year-to-year basis. The observed variations in cadence rates may be associated with viral epidemics, sunshine exposure, or vitamin D levels and suggest further exploration of these relations.

Binocular fixation topography in patients with diabetic macular oedema: possible implications for photocoagulation therapy (3rd revision)

BACKGROUND

During retinal photocoagulation for diabetic maculopathy, there is a potential risk of foveal burns, and laser scars may later enlarge to be sight-threatening when involving retinal areas previously used during fixation. Since the retinal area used during binocular steady fixation has been found to vary considerably in the normal test person and central fixation may be even further compromised in patients with diabetic maculopathy, the sight-threatening side effects could possibly be reduced by taking into account the fixation area individually. However, no study has described and quantified the retinal area of fixation binocularly in patients with clinically significant macular oedema (CSME).

METHODS

Sixteen diabetic patients with CSME in one or both eyes were examined. Each examination included visual acuity testing (ETDRS charts), a standard eye examination, central retinal thickness assessment by optical coherent tomography, fluorescein angiography and binocular quantification of fixational eye movements using an infrared recording technique.

RESULTS

A negative correlation was found between visual acuity and mean microsaccadic amplitude (R=0.48, p=0.009). The maximal retinal extension of the fixation area ranged between 1.0 degrees and 3.0 degrees , and in two eyes with CSME, this area was estimated to exceed 800 mum on the retinal plane. No correlation was found between retinal thickness and visual acuity, retinal area of fixation, maximal extension of the fixation area or mean microsaccadic amplitude.

CONCLUSION

Large interindividual differences in quantitative measures of binocular fixational eye movements were found. The mean amplitude of fixational eye movements was not correlated to central retinal thickness, and fixation area could only partly be predicted by visual acuity. Two eyes with CSME had an estimated maximal extension of the fixation area exceeding the central 800 mum on the retinal plane; thus, the possible benefit of individualising central photocoagulation according to precise measures of fixation area needs to be investigated on a larger population.

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%.

Bayesian approach to study the temporal trend and the geographical variation in the risk of type 1 diabetes. The Sardinian Conscript Type 1 Diabetes Registry

BACKGROUND

A previous analysis of the Sardinian Conscript Type 1 Diabetes Registry indicated an abrupt increase in the risk for type 1 diabetes (T1D) among Sardinian male cohorts starting from the 1946 one.

OBJECTIVE

The aim of this study was to update the point prevalence of T1D among Sardinian male army conscripts aged 18 yr from 1992 to 1997 described in the previous survey and to update its secular trend. It also looked at the geographical distribution of prevalence.

SUBJECTS AND METHODS

All male Italian citizens must appear before the Conscript Board for a clinical examination prior to military service. T1D patients are rejected with T1D listed as the reason. We examined, retrospectively, a total of 83807 Sardinian males aged 18, born between 1 January 1974 and 31 December 1979. They virtually represent the whole Sardinian population of that age and sex.

RESULTS

A total of 307 subjects with T1D were identified. T1D point prevalence for the birth cohorts 1974-1979 was 3.66/1000 (95% CI 3.28-4.09). Bayesian analysis of the geographical distribution of prevalence shows the highest rate in the Southern part of the island (Cagliari province) and the lowest in the north-western part (Sassari province). A similar picture was produced by data from the Eurodiab Registry in Sardinia (1989 ongoing). No significant temporal trend of prevalence was seen in the 6 yr examined in the current study; pooling these recent birth cohorts with the previous ones, the increasing trend of prevalence was confirmed.

CONCLUSIONS

Our data confirmed the South to North gradient of T1D and the progressive increase of T1D risk among males in Sardinia.

The rise of childhood type 1 diabetes in the 20th century

The incidence of childhood type 1 diabetes increased worldwide in the closing decades of the 20th century, but the origins of this increase are poorly documented. A search through the early literature revealed a number of useful but neglected sources, particularly in Scandinavia. While these do not meet the exacting standards of more recent surveys, tentative conclusions can be drawn concerning long-term changes in the demography of the disease. Childhood type 1 diabetes was rare but well recognized before the introduction of insulin. Low incidence and prevalence rates were recorded in several countries over the period 1920-1950, and one carefully performed study showed no change in childhood incidence over the period 1925-1955. An almost simultaneous upturn was documented in several countries around the mid-century. The overall pattern since then is one of linear increase, with evidence of a plateau in some high-incidence populations and of a catch-up phenomenon in some low-incidence areas. Steep rises in the age-group under 5 years have been recorded recently. The disease process underlying type 1 diabetes has changed over time and continues to evolve. Understanding why and how this produced the pandemic of childhood diabetes would be an important step toward reversing it.

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

OBJECTIVE

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

RESEARCH DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Viruses and diabetes

Insulin-dependent diabetes mellitus (IDDM) is a multifactorial disease. Besides a genetic predisposition environmental factors have been implicated in the pathogenesis of beta cell destruction. Among these environmental factors viruses have been the focus of many studies. Some viruses are diabetogenic in animals, and others have been implicated as triggers in human IDDM by temporal and geographical association between IDDM and viral infections, serological evidence of infection in recently diagnosed diabetic patients, and the isolation of viruses from the pancreas of affected individuals. We discuss possible pathomechanisms of viral infections in beta cell destruction and review the studies on involvement of enteroviruses, retroviruses, rubella viruses, cytomegaloviruses, and Epstein-Barr viruses in human IDDM. We also report on studies of diabetogenic viruses in animal models as well as on viral infections protecting from IDDM. Some of the difficulties in linking viral infections to IDDM will be illustrated with data from a transgenic mouse model in which IDDM can be precipitated by infections with certain strains of lymphocytic choriomeningitis virus (LCMV). Emerging treatment concepts that do not rely on defining the initiating autoantigens but involve self-reactive regulatory lymphocytes such as oral antigen administration, as well as DNA vaccines, will be discussed briefly.

Is one 60 degrees fundus photograph sufficient for screening of proliferative diabetic retinopathy?

OBJECTIVE

To compare one 60 degrees fundus photograph to seven field stereo fundus photographs in identifying proliferative diabetic retinopathy.

RESEARCH DESIGN AND METHODS

A total of 44 eyes in 23 patients with moderate/severe nonproliferative diabetic retinopathy were included. Evaluation of each eye was based on one 60 degrees fundus photograph. Eyes were re-examined using seven field 30 degrees stereo fundus photographs according to the protocol of the Early Treatment Diabetic Retinopathy Study, and the photographs were examined independently by three ophthalmologists to identify retinal neovascular lesions. In addition, fluorescein angiography was performed in all patients to verify the presence of the lesions.

RESULTS

In four eyes of three patients (11.1% of eyes) evaluated based on seven field stereo photographs, retinal neovascularization was found. This condition was not found on examination of 60 degrees fundus photographs.

CONCLUSIONS

Examination of one 60 degrees fundus photograph was found to be insufficient as a screening procedure in patients with moderate/severe nonproliferative diabetic retinopathy.

The rising incidence of childhood type 1 diabetes in New South Wales, Australia

OBJECTIVES

1. To determine the incidence of type 1 (insulin dependent) diabetes in children aged 0-14 years who were resident in the state of New South Wales, Australia over the period 1992-1996. 2. To analyse the trends in incidence over the period 1990-1996.

METHODS

Primary ascertainment of patients was performed using a prospective incidence register established in 1990. The secondary source of ascertainment was the National Diabetes Supply Scheme, a government subsidised scheme for diabetic supplies.

RESULTS

There were 1,230 patients identified over the five-year period. Using the capture-recapture method, ascertainment was estimated to be 99% complete. The lowest incidence occurred in 1992 (16.9 per 10(5) person years) and the highest incidence was in 1995 (21.7 per 10(5)). The crude incidence of IDDM from 1990-1996 was 17.8 per 10(5) and there was a statistically significant rise in the incidence of type 1 diabetes over this period (p=0.0003). The annual incidence has increased on average by 3.2% per year since 1990.

CONCLUSION

The incidence of childhood type 1 diabetes in NSW has increased significantly since 1990.

Incidence of type I diabetes mellitus in Navarre, Spain (1975-91)

The aim of this study was to ascertain the incidence of Type 1 diabetes mellitus in Navarre, an autonomous community in northern Spain. Subjects were patients who presented with diabetes between 1975 and 1991, age range 0-16 years, resident in Navarre at the onset of symptoms. Endocrinologists in outpatient centres and hospitals (both public and private) in Navarre were the primary source of data, while secondary sources were: independent general practitioners, health centre paediatricians and the Child-Youth Diabetics Parents' Association of Navarre. The degree of ascertainment was 97.8%. Average annual incidence of diabetes detected was 9.54/100000 (95% CI 8.2-11.1) in the 0-14 year-old group. The least incidence was observed in 1976 and highest in 1990. The incidence in males (9.71/100000) was higher than in females (7.83/100000). The highest incidence was observed in the 10-14 year-old group (13.70/100000) when analysed by groups. No seasonal variation in the onset of diabetes was observed. These results suggest a significant increase in the incidence of type 1 diabetes between 1975 and 1991.

Cancer and diabetes--a follow-up study of two population-based cohorts of diabetic patients

OBJECTIVES

To study the occurrence of cancer amongst patients with diabetes mellitus (DM).

DESIGN

Population based cohort study.

SETTING

Denmark.

SUBJECTS

Two cohorts of patients with DM were identified. One cohort comprised 1659 conscripts diagnosed with type I DM before the age of 20 years. Another cohort comprised 1499 men and women with insulin treated DM identified by means of medical prescriptions on 1 July 1973. Both cohorts were followed until the end of 1992.

MAIN OUTCOME MEASURES

The relative risk of cancer in the two cohorts was estimated as the ratio of observed to expected number of cancers in the cohort (SIR).

RESULTS

No unusual risk of cancer was observed amongst the conscripts (SIR 0.9, n = 13) or amongst patients with onset of DM before the age of 30 years in the prescription cohort (SIR 0.9, n = 32). Amongst those aged 30 years or more at DM onset in the prescription cohort, the overall risk of cancer did not depart from normal (SIR 1.0, n = 103), however, pancreatic cancer occurred in excess both immediately (< 1 year) (SIR 190, n = 1), and during 1-9 years after DM onset (SIR 9.0, n = 4). Similarly, the risk of non-Hodgkin's lymphoma was increased significantly (SIR 3.3, n = 6), all cases occurring more than 10 years after DM onset.

CONCLUSIONS

Our data suggest that there is no unusual risk of cancer associated with type I DM. Type II DM may be the first symptom of pancreatic cancer and may be associated with an increased risk of non-Hodgkin's lymphoma.

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.

Variation by age group and seasonality at diagnosis of childhood IDDM in Europe. The EURODIAB ACE Study Group

Recent data provided by the EURODIAB ACE study group have confirmed wide variation in the incidence of insulin-dependent diabetes mellitus (IDDM) across Europe. The aim of this report is to compare age-specific incidence and seasonality at clinical onset of IDDM between study regions. Using a uniform methodology, the EURODIAB ACE framework ascertained 3,168 newly-diagnosed cases of IDDM in children under the age of 15 years during 1989-1990. Eighteen percent of the cases were age 0-4 years at diagnosis, 34% were age 5-9 years and 48% were age 10-14 years. Poisson regression analysis suggested that there were highly significant statistical differences in incidence between the three age groups and between the 24 regions. Although incidence rates in the 0-4 year and 5-9 year age groups varied from region to region in a similar fashion, the pattern of variation in the older age group was different. Seasonality of diagnosis conformed to a sinusoidal model with a peak occurring in winter, a feature which was consistently observed in both sexes and in all age groups. However, a statistically significant heterogeneity in the seasonal distribution was present among regions, those in Scandinavia showing the smallest relative amplitude. The first insulin injection was given the same day or the day after diagnosis in 93% of the cases for whom data were available.

Molecular genetics of diabetes mellitus

As a result of advances in technology, genome searches have been carried out for susceptibility genes for type 1 diabetes in humans and in the NOD mouse. These have shown that, in the NOD mouse, diabetes susceptibility is under the control of at least ten separate chromosomal loci. In the human, in addition to HLA and INS, two new susceptibility genes have been localized, IDDM4 on chromosome 11q and IDDM5 on 6q, demonstrating the polygenic nature of type 1 diabetes and the role of HLA as the major locus. Candidate genes at these loci are the subject of current investigation. Genetic and immunological markers of disease may be of value in screening the general population for individuals at risk of developing type 1 diabetes. The predictive power of different screening strategies should be tested in order to work out the potential value to the general population of preventive therapies that are now undergoing clinical trials in high risk 'pre-diabetics'. Type 2 diabetes is genetically heterogeneous, and, since 1992, two distinct genetic subtypes have been identified. The first is defined by mutations in the GCK gene, which cause up to 60% of cases of MODY. The second, designated MIDD (maternally inherited diabetes and deafness), is defined by mutation in the mitochondrial gene for tRNA(Leu(UUR)). MIDD patients are less obese than is usual for typical type 2 diabetes, may present in early adult life or occasionally in childhood and may have been diagnosed as having autoimmune type 1 diabetes, type 2 diabetes or MODY. Typically, patients with MIDD require insulin earlier than do type 2 diabetics without mitochondrial mutations. Genetically complex diseases, such as diabetes, hypertension, cancer and coronary heart disease, are common in most populations. The approaches to the genetic analysis of diabetes outlined in this review are likely to be useful to the genetic analysis of many of these disorders. Progress in this area will have important implications for public health strategies in the next decade and beyond.

The Verona diabetes study: a population-based survey on known diabetes mellitus prevalence and 5-year all-cause mortality

This population-based survey aimed to determine the prevalence of known diabetes mellitus on 31 December 1986, and to assess all-cause mortality in the subsequent 5 years (1987-1991) in Verona, Italy. In the study of prevalence, 5996 patients were identified by three independent sources: family physicians, diabetes clinics, and drug prescriptions for diabetes. Mortality was assessed by matching all death certificates of Verona in 1987-1991 with the diabetic cohort. Overall diabetes prevalence was 2.61% (95% confidence interval 2.56-2.67). Prevalence of insulin-dependent and non-insulin-dependent diabetes mellitus was 0.069% (0.059-0.078) and 2.49% (2.43-2.54), respectively. Diabetes prevalence sharply increased after age 35 years up to age 75-79, and finally declined. Prevalence was higher in men up to age 69 years, in women after age 75 years. Of the diabetic cohort 1260 patients (592 men, 668 women) died by 31 December 1991, yielding an overall standardized mortality ratio of 1.46 (CI 1.38-1.54). Even though the differences narrowed with age, mortality rates in the diabetic cohort were higher than in the non-diabetic population at all ages. Women aged 65-74 years showed observed/expected ratio higher than men (2.27, CI 1.92-2.66, vs 1.50, CI 1.30-1.72), while in other age groups the sex-related differences were not significant. Pharmacological treatment of diabetes was associated with an excess mortality, while treatment with diet alone showed an apparent protective effect on mortality (observed/expected ratio 0.73, CI 0.58-0.92).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased prevalence of insulin-treated diabetes mellitus in Funen County, Denmark

OBJECTIVE

To determine the prevalence of insulin-treated diabetes mellitus in Funen County, Denmark as of 1 July 1987 and compare the findings with those of a similar study from 1973.

DESIGN

The population was identified by insulin prescriptions collected during a 1 year period. The identity of the prescription holders, the diagnosis and the date of diagnosis were verified from medical records and public registers.

RESULTS

The estimated degree of ascertainment of the material is 0.95-0.97. The prevalence rates (per 1000 of the population) of insulin-treated diabetes mellitus as of 1 July 1987 are: 4.74 (95% Cl 4.66-4.82) for all cases, 2.08 (95% Cl 2.01-2.15) for the group with onset of diabetes before age 30 years and 2.66 (95% Cl 2.59-2.73) for the group with onset after age 30 years. These figures correspond to increases of 39, 26 and 51% (P < 0.001) on data collected in 1973.

CONCLUSIONS

There was a significant increase in the prevalence of insulin-treated diabetes mellitus in Funen County, Denmark from 1973 to 1987. Analysis of the data shows that an important factor for this increase is a liability to start insulin treatment of type 2 (non-insulin-dependent) diabetes mellitus at an earlier stage than previously. Also, the data suggest that improved prognosis for diabetic patients as well as an increasing incidence of diabetes mellitus are factors involved in the increase.

A review of the recent epidemiological data on the worldwide incidence of type 1 (insulin-dependent) diabetes mellitus. World Health Organization DIAMOND Project Group

Nearly 70 registries from more than 40 countries have collected and published incidence data of childhood Type 1 (insulin-dependent) diabetes mellitus up to the end of the 1980s. The majority of incidence data comes from regions of high incidence i.e. from Europe and North America. All these published data facilitate the descriptive comparison of incidence and variation of the occurrence of Type 1 diabetes roughly throughout the northern hemisphere. The aim of this paper is to review and compare the most recent epidemiology data on the incidence of Type 1 diabetes among children under the age of 15 years. A clear difference in incidence appeared between northern and southern hemisphere with no countries below the equator having an incidence greater than 15.0 per 100,000. In contrast above the equator the disease is common. Between continents the variation in incidence showed that the lowest incidences were found in Asia, followed by Oceania (Australia and New Zealand), South and North America, and the highest rates were in Europe. The incidence varied from 0.6 per 100,000 in Korea and Mexico to 35.3 per 100,000 in Finland showing prominent worldwide variation in incidence of Type 1 diabetes. The largest intracontinental variation in incidence appeared in Europe, varying from the highest in Finland to the lowest (4.6 per 100,000) in northern Greece. The highest incidence in the world was in northern Europe, but within the continent scale there were some striking exceptions from the overall level of incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Increasing prevalence of juvenile onset type 1 (insulin-dependent) diabetes mellitus in Sardinia: the military service approach

In order to obtain new and more detailed information about temporal trends and geographic distribution of Type 1 (insulin-dependent) diabetes mellitus in Sardinia, we screened a series of birth cohorts (1936-1973) of all male army conscripts aged 18-19 years, filed in the Sardinian Conscript Register where Type 1 diabetes is a cause of rejection. A total of 678 diabetic subjects, born and permanently residing in Sardinia, was identified. The point prevalence (x 1000) at the age of 20 years in the birth cohorts ranged from values close to zero for the first ten cohorts (1936-1945) up to a maximum of 3.08 (95% confidence limits 2.28-4.08) for the 1966 cohort and continued high thereafter although an apparent decrease was observed from the early 1970s birth cohorts. Type 1 diabetes was distributed throughout the four provinces of Sardinia with no particularly significant heterogeneity; however, in accordance with the geographical distribution of diabetes cases of the Eurodiab Ace survey (1989-1990), the highest prevalence of the disease was observed in the Cagliari and Oristano provinces, followed by Nuoro and Sassari. These data suggest a gradually increasing trend of male Type 1 diabetes prevalence in Sardinia with a 29-fold increase between the late 1930s and the late 1960s birth cohorts. This seems to confirm the high incidence of Type 1 diabetes in the 0-14 and 0-29 year age groups recently reported among Sardinians during the Eurodiab Ace collaborative multicentre study.

Type I diabetic nephropathy: clinical characteristics and economic impact

Approximately one-third of type I diabetic patients develop diabetic nephropathy with confounding pathogenesis--frequently manifested as heavy persistent proteinuria, fall in glomerular filtration rate, and increased arterial hypertension. There is increasing incidence and prevalence of type I diabetes, particularly in northern Europe and the United States. Increased morbidity and mortality occur in type I diabetic patients with renal disease. Among type I patients with persistent proteinuria, death occurs on the average within 5-10 years. The economic impact of endstage renal disease due to diabetic nephropathy is overwhelming, and the cost is increasing at an alarming rate.