Genetic predisposition and environmental factors leading to the development of insulin-dependent diabetes mellitus in Chilean children.

This study was designed to examine the hypothesis that some environmental factors increase the risk for insulin-dependent diabetes mellitus. Data on dietary history was collected from 80 diabetic children from the Santiago de Chile Registry and from 85 nondiabetic control subjects who were comparable in terms of age, sex, and ethnic characteristics. Early exposure was defined as the ingestion of food sources other than maternal milk before 3 months of age. To define genetic susceptibility to insulin-dependent diabetes mellitus each subject was typed in terms of HLA DQA1 and DQB1, and the possible conformation of susceptible heterodimers was considered as a risk marker. Fewer children were exclusively breast fed in the diabetic group than in the control group (21.55 +/- 15.05 vs 33.95 +/- 20.40 weeks, P<0.01). In addition, exposure to cow's milk and solid foods occurred earlier in the diabetic group than in the control group (15.90 +/- 10.95 vs 21.15 13.65 and 16.85 +/- 10.25 vs 21.20 +/- 12.35 weeks, P<0.05). Our data show that a short duration of breast-feeding and early exposure to cow's milk and solid foods may be important factors in the development of insulin-dependent diabetes mellitus. The high relative risk observed in individuals genetically predisposed indicates an interaction effect between genetic and environmental components.

[HLA and insulin-dependent diabetes mellitus]. / HLA y diabetes mellitus insulinodependiente.

The propensity of an individual to develop type I (insulin dependent) diabetes mellitus is directly related to specific HLA class II proteins, specially those from DR and DQ regions. Genetic susceptibility to insulin dependent diabetes arises from a preestablished conformation of alpha and beta chains of DQ and beta chain of DR. Since the classic demonstration by McDevitt and colleagues that DQ beta chain aspartate at position 57 was protective against the development of the disease, many populations have been surveyed to study the association between the incidence Type I diabetes and determined frequencies of DR and DQ haplotypes. The association between these markers and susceptibility to Type I diabetes is well established in caucasians at the present time. However, little information is available for Latin American populations, that share a mixture of european, african and native genes. Our group is studying genetic markers of three Latin American populations (Argentina, Perú and Chile) and their possible association to the different incidence of Type I diabetes mellitus in each country.

[Lipoprotein (a) and other risk factors in Chilean children with type I diabetes mellitus]. / Lipoproteina (a) y otros factores de riesgo en niños chilenos con Diabetes Mellitus Tipo I.

AIMS: To study serum Lp(a) levels and other metabolic cardiovascular risk factors in children with type I diabetes mellitus (DM) in comparison with sex and age matched nondiabetic children. To determine the influence of diabetes control on serum lipoprotein (a) concentrations. DESIGN: Transversal observational study. TARGET POPULATION: diabetic group: 70 type I DM children without microalbuminuria and no macro-microvascular nor neurological complications, aged from 8 to 15 years; 30 boys, 40 girls. Mean duration of type I DM was 8 +/- 4 years. Non diabetic group: composed by 123 healthy children with no family history of DM, aged from 8 to 15 years, 53 boys, 70 girls. METHODS: The lipids profile include: total cholesterol (TC) and triglyceride (TG), cholesterol high-density lipoproteins (C-HDL) cholesterol very-low-density lipoproteins (C-LDL) and cholesterol low-density lipoproteins (C-LDL). ApoAI, APOAII and ApoB, Lp(a) and fructosamine. RESULTS: Fructosamine concentration in diabetic children was 340 +/- 108 uM/1 in 240 +/- 25 uM/l nondiabetic children. Lp(a) serum levels did not significantly differ among both groups 17 +/- 16 mg/dl in diabetics 19 +/- 18 mg/dl in controls. Multivariate analysis showed that in the diabetic children the worsening of metabolic control as reflected by fructosamine, was positively correlated with the increase in total Lp(a) serum concentration. CONCLUSIONS: In children aged 8-15 years with uncomplicated IDDM lasting less than 15 years duration, Lp(a) serum levels are positively correlated with the poorest metabolic control.

[Lipoprotein (a), atherosclerosis, and diabetes mellitus]. / Lipoproteina (a), aterosclerosis y diabetes mellitus.

Diabetes mellitus is associated with a three to fourfold increased risk for coronary artery disease and diabetic patients frequently have an abnormal plasma lipid profile. Lately, lipoprotein (a) has received attention as an important independent risk factor for cardiovascular disease. This lipoprotein is elevated in patients with type II diabetes mellitus and there may be an association between the metabolic control of these subjects and its levels. In this review the main features of lipoprotein (a) and its relationship to the fibrinolytic system and atherosclerosis are reviewed.