Gender differences and temporal variation in the incidence of type 1 diabetes: results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002.

OBJECTIVES: To establish the gender difference amongst newly diagnosed type 1 diabetic patients aged 15-34 years, considering age at diagnosis, temporal trend and seasonal variation at time of diagnosis. STUDY DESIGN: A population-based prospective study with a mean annual population at risk of 2.3 million. SETTING: All departments of medicine, endocrinology and paediatrics and primary health care units in Sweden. SUBJECTS: Incident cases of diabetes aged 15-34 years at diagnosis 1983-2002. MEASURE INSTRUMENT: Basic characteristics of patients at diagnosis were reported by the diagnosing doctor on a standardized form. Level of ascertainment was estimated at 80-90%. RESULTS: Amongst all incident cases (n = 8012), 74% was diagnosed with type 1 diabetes. The mean annual incidence rate of type 1 diabetes was 12.7/100,000, in men 16.4/100,000 and in women 8.9/100,000. The incidence of type 1 diabetes decreased slowly by increasing age but was in all age groups higher in men, yielding an overall male/female ratio of 1.8. In both genders the incidence of type 1 diabetes decreased in average of 1.0% per year. A seasonal pattern with significantly higher incidence during January-March and lower during May-July was seen in both genders. CONCLUSIONS: A clear male predominance of type 1 diabetes was seen in all ages. The temporal trend and the seasonal pattern was similar in men and women. Hence, internal factors related to the gender rather than differences in the exposure to environmental factors seem to explain the consistent male-female bias in the postpubertal risk of developing type 1 diabetes.

The Swedish Childhood Diabetes Study--a multivariate analysis of risk determinants for diabetes in different age groups.

In a nationwide incident case-referent study stepwise univariate analysis has revealed several risk determinants for childhood diabetes mellitus. In a multivariate analysis we have determined the set of risk determinants that would independently predict childhood Type 1 (insulin-dependent) diabetes. Possible interactions between the risk determinants and differences in risk profiles with different ages at onset were also examined. Reported familial insulin-treated and non-insulin-treated diabetes were significant risk factors in all age groups, as was also a low frequency of milk intake. The frequency of infections and a high intake of foods rich in nitrosamine tended to interact (OR 11.8, p = 0.053) indicating a synergistic effect. A Cox regression analysis revealed that stressful life events during the last year was the only variable that tended to affect the age at onset (p = 0.055). This indicated that psychological stress may rather precipitate than induce Type 1 diabetes. A short breast-feeding duration (OR = 3.81), and an increased body height (OR = 3.82) contributed significantly to the predictive model in only the youngest age group (0-4 years). An increased frequency of infections in the year preceding onset (OR = 2.15) and no vaccination against measles (OR = 3.33) contributed significantly to the model only in the age group 5-9 years. Various nutrients had different impacts on the risk of developing Type 1 diabetes in different age groups. It is concluded that in the genetically susceptible child, risk factors which are associated with eating habits, frequency of infections, vaccination status, growth pattern and severe psychological stress affect the risk of developing diabetes independently of each other.(ABSTRACT TRUNCATED AT 250 WORDS)

The Butajira project in Ethiopia: a nested case-referent study of under-five mortality and its public health determinants.

During one year of follow-up, 306 deaths of children under the age of 5 years were included in a concurrent case-referent study that was based on a population estimated at 28,780 in 1987. A total of 612 live referents, matched for age, sex and study area, were also selected from the study population through density sampling. Data were collected by lay reporters by verbal autopsy. For the study period the estimated cumulative under-five mortality rate was 293 and the infant (0-11 months old) mortality rate was 136 per 1000. Major probable causes of death were diarrhoeal disease or acute respiratory infections (ARI). The relative importance of parental and environmental characteristics was assessed using conditional multiple logistic regression analysis. Under-five mortality was associated with paternal illiteracy, maternal ethnicity, and not being in the committee of people's organizations. Parental factors affected the infants relatively more than they did the children, especially with regard to ARI mortality. This was also noted with "absence of window", a proxy measure for evaluating the type of housing. In terms of etiological fractions a greater number of under-five deaths could be ascribed to parental than environmental conditions, with relatively more infants being affected than children.

PIP: In Butajira district, Ethiopia (130 km south of Addis Ababa), 2 trained field workers went to each household of 306 5 children who died between October 1988 and September 1989 and of 612 age, sex, and study area matched referents to interview caretakers as part of a study analyzing determinants of 5 mortality, especially parental and environmental determinants. Leading causes of infant and child deaths were acute respiratory infections (ARI) (33 and 20%, respectively) and diarrheal disease (23 and 32%, respectively). The multivariate analysis showed that Silti ethnicity of the mother (odds ration = 1.74), paternal illiteracy (OR = 1.45), and nonmembership in people's organizations (OR = 1.95) were parental risk factors. All children with all 3 parental factors were at a 4.6 times higher risk of 5 mortality than those with no parental risk factors. Infants with 3 parental risk factors were at a considerably greater mortality risk than were 1-4 year old children with 3 parental risk factors (OR, 10.7 vs. 2.5). Children with 3 parental risk factors living in the highlands faced a higher risk of death than those in the lowlands (15.5 vs. 2.8). 3 parental risk factors carried a higher risk of mortality pursuant to ARI than to diarrhea (14.8 vs. 2.4). The only environmental risk factor was no window in the house (OR = 1.54). Absence of windows was especially risky for infants (OR = 2.7) and for children with ARI (OR = 1.8 vs. 1.3 with diarrhea). Lack of windows was linked to crowding and poor housing. Public health interventions to eliminate parental or environmental factors would result in 55% or 31% fewer deaths, respectively. These findings suggest that parental factors have a greater impact on 5 mortality than environmental factors and that both parental and environmental factors and that both parental and environmental factors have a greater impact on infant than on child mortality.

The Swedish childhood diabetes study: indications of severe psychological stress as a risk factor for type 1 (insulin-dependent) diabetes mellitus in childhood.

This study is part of a nationwide case-referent study. All recent-onset Type 1 (insulin-dependent) diabetic children aged 0-14 years in Sweden were invited to participate. Referent subjects matched for age-, sex- and geographical distribution were selected. In all, 338 patients and 528 referent subjects took part. Life events during the last year prior to clinical onset of Type 1 diabetes were recorded on a questionnaire. The total frequency of life events did not differ between diabetic and referent children. However, qualitatively the life events reported by diabetic children revealed a tendency to increased severity. Events related specifically to actual or threatened losses within the family--events that may affect children differently in different age groups--were reported with a significantly higher frequency by diabetic patients than by referent subjects, aged 5-9 years. The relative risk that such events in fact comprise a risk factor for Type 1 diabetes was 1.82 (95% confidence limits 1.09, 3.03). The relative risk was significantly increased even when standardized for possible confounding factors such as age, sex and indices of social status of the family. We conclude that stressful life events, related to actual or threatened losses within the family, occurring in the vulnerable age group of 5-9 years, are associated with the onset of childhood Type 1 diabetes. Such stressful events may in fact be a risk factor for the disease.