A Comparison of Childhood and Adult Type I Diabetes Mellitus

TLDR

The incidence rate of insulin‑dependent (Type I) diabetes mellitus is bimodal, peaking near puberty and again in the fifth decade. The study aimed to evaluate differences between childhood and adult onset Type I diabetes by examining clinical, biochemical, autoimmune, and genetic features. The authors compared 82 children/adolescents and 44 adults at diagnosis, assessing these features. Adults presented with a longer symptomatic period, higher C‑peptide levels indicating better residual beta‑cell function, and lower insulin autoantibody prevalence and HLA‑D3/D4 heterozygosity compared to children, while other clinical and genetic markers were similar between groups. N Engl J Med 1989; 320:881–6.

Abstract

The incidence rate of insulin-dependent (Type I) diabetes mellitus is bimodal: one peak occurs close to puberty, and the other in the fifth decade. To evaluate possible differences in these forms of the disease, we examined the clinical, biochemical, autoimmune, and genetic features of 82 children and adolescents (1.3 to 18.2 years old) and 44 adults (20.0 to 55.8 years old) when they presented with Type I diabetes. The mean (±SEM) duration of symptoms before diagnosis was longer in the adults (7.5±1.0 vs. 3.9±0.4 weeks; P<0.001), and their serum C-peptide concentrations at diagnosis were higher (0.29±0.03 vs. 0.17±0.01 nmol per liter; P<0.001), suggesting that they had more residual beta-cell function. There were no significant differences between the two groups in sex ratio, blood glucose levels, hemoglobin A1 values, degree of metabolic decompensation, or frequency of Type I diabetes in first-degree relatives. Thirty-four of 80 children tested (42.5 percent) were positive for insulin autoantibodies, as compared with only 1 of 26 adults (3.8 percent; P<0.001). However, the frequencies of islet-cell autoantibodies were similar in the adults and children (conventional autoantibodies, both 81 percent; complement-fixing autoantibodies, 46.2 percent and 60 percent). More children than adults were heterozygous for both HLA-Dw3/4 antigens (26.6 percent vs. 9.8 percent; P<0.05) and HLA-DR3/4 antigens (36.6 percent vs. 12.5 percent; P<0.05). We conclude that Type I diabetes that begins in adulthood is characterized by a longer symptomatic period before diagnosis, better preservation of residual beta-cell function, and lower frequencies of insulin autoantibodies and HLA-D3/D4 heterozygosity than Type I diabetes that begins in childhood or adolescence. (N Engl J Med 1989; 320:881–6.)