The clinical presentation of type 1 diabetes at a very young age is associated with severe metabolic decompensation, poorly preserved residual beta-cell function, strong humoral autoimmunity against islet cells and insulin, and strong HLA-defined disease susceptibility.

A nationwide study of childhood Type 1 (insulin-dependent) diabetes mellitus was established in 1986 in Finland, the country with the highest incidence of this disease worldwide. The aim of the project called "Childhood Diabetes in Finland" is to evaluate the role of genetic, environmental and immunological factors and particularly the interaction between genetic and environmental factors in the development of Type 1 diabetes. From September 1986 to April 1989, 801 families with a newly-diagnosed child aged 14 years or younger at the time of diagnosis were invited to participate in this study. The vast majority of the families agreed to participate in the comprehensive investigations of the study. HLA genotypes and haplotypes were determined in 757 families (95%). Our study also incorporates a prospective family study among non-diabetic siblings aged 3-19 years, and two case-control studies among the young-onset cases of Type 1 diabetes. During 1987-1989, the overall incidence of Type 1 diabetes was about 35.2 per 100,000 per year. It was higher in boys (38.4) than in girls (32.2). There was no clear geographic variation in incidence among the 12 provinces of Finland. Of the 1,014 cases during these 3 years only six cases were diagnosed before their first birthday. The incidence was high already in the age group 1-4-years old: 33.2 in boys and 29.5 in girls. Of the 801 families 90 (11.2%) were multiple case families, of which 66 had a parent with Type 1 diabetes at the time of diagnosis of the proband.(ABSTRACT TRUNCATED AT 250 WORDS)

The determinants of the degree of metabolic decompensation at the diagnosis of type 1 (insulin dependent) diabetes mellitus (IDDM) and the possible role of diabetic ketoacidosis in the preservation and recovery of residual P cell function were examined in 745 Finnish children and adolescents. Children younger than 2 years or older than 10 years of age were found to be more susceptible to diabetic ketoacidosis than children between 2 and 10 years of age (<2 It is well known that the capacity of residual 5 cells to secrete insulin is decreased at the time of diagnosis of IDDM, often improving in a few weeks after the initiation of exogenous insulin treatment.8'-`The extent of improvement in insulin secretory capacity has been observed to be associated with age at diagnosis,' degree of metabolic decompensation,9 mild clinical symptoms at diagnosis,2910 and strict initial blood glucose control.2 13 Diabetic ketoacidosis is a serious consequence of insufficient insulin secretion.'4 In addition to possible acute complications, it may also influence the later outcome of diabetes.To study the effect of age, sex, and socioeconomic factors on the clinical condition of the patient at the diagnosis of IDDM, and to find out whether metabolic decompensation at diagnosis is related to subsequent endogenous insulin secretion and impaired metabolic control, 745 Finnish children and adolescents, aged 0.8-14.9 years, were evaluated at the time of diagnosis of IDDM and then observed for two years. Methods PATIENTSAs a part of the Finnish nationwide 'Childhood diabetes in Finland' study,'5 801 probands younger than 15 years, diagnosed as having IDDM during the recruitment period from 1 September 1986 to 30 April 1989, were offered the possibility of participating in the study. Of these 745 had analyses of blood pH, serum C peptide concentrations, and blood glycated haemoglobin levels at the time of hospital admission. At the time of admission, a clinical examination including assessment of consciousness and dehydration was performed, and the parents were asked to fill out a questionnaire concerning the socioeconomic status of the family. The subjects were then followed up in their own outpatient clinics (n = 31) for two years. At six month intervals, the recommended amount of insulin was recorded, blood specimens werc taken for glycated haemoglobin and serum C peptide concentrations, and a clinical examination including height and weight recording was performed.The mean age of the probands was 8.4 years (range 0.8 to 14.9 years). The majority of them were males (n = 412; 55.3%). The subjects were divided into two groups: those with and without diabetic ketoacidosis at diagnosis. In the longitudinal study the groups were compared at the time of diagnosis and at six, 12, 18, and 24 months after diagnosis. LABORATORY MEASUREMENTSCapillary or venous blood pH was measured at the time of hospital admission. Diabetic

The protective effects of a long duration of breast-feeding and a late introduction of dairy products on the risk of IDDM remained significant after adjusting for the mother's education.

The intakes of nitrate and nitrite of children and their parents from food and drinking water were estimated in a Finnish nation-wide case-control study on the epidemiology of Type 1 diabetes. The study population consisted of 684 case and 595 control children; 548 case-control pairs of fathers; and 620 case-control pairs of mothers. The consumption frequencies of foods which are important sources of nitrate and nitrite were assessed by structured questionnaire. Nitrate and nitrite concentration data were collected from Finnish water works. Diabetic children's and their mothers' daily dietary intake of nitrite was greater compared with that of control children and mothers (for case and control children 0.9 mg vs 0.8 mg, for case and control mothers 0.9 mg vs 0.8 mg, p < 0.001). Case mothers compared with control mothers received less (p < 0.05) nitrate from their diet. No differences were observed in the intake of nitrate or nitrite from drinking water. Dietary nitrite intake of children (odds ratios and 95% confidence intervals for the second, third, and fourth quartile 1.16, 0.82-1.65; 1.49, 1.06-2.10; 2.32, 1.67-3.24, respectively) and mothers (odds ratios and 95% confidence intervals for the second, third, and fourth quartile 1.15, 0.76-1.74; 1.29, 0.87-1.91; 1.98, 1.35-2.90, respectively) was positively associated with the risk for Type 1 diabetes independently from length of mother's education, child's or mother's age, place of residence or mother's smoking status.(ABSTRACT TRUNCATED AT 250 WORDS)