Analysis of weight at birth and at diagnosis of childhood-onset type 2 diabetes mellitus in Japan

Abstract

The prevalence of childhood-onset type 2 diabetes mellitus (T2DM) has increased dramatically over the past two to three decades in Japan, but epidemiological and clinical data remain limited. Several epidemiological studies stress the importance of elucidating the pathophysiology of prenatal nutrition and other intra-uterine environmental factors and the risk of T2DM in each of the different populations. We examined the associations of weight at birth, weight at diagnosis of T2DM, and clinical characteristics of childhood-onset T2DM.Clinical data sheets were sent to councillors of the Japanese Society for Pediatric Endocrinology (JSPE) and members of the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) in June 2003. Clinical data on 259 children (9-17 yr of age) categorized as T2DM by pediatric endocrinologists, who are members of the JSPE and/or JSGIT, using 1999 Japan Diabetes Society criteria were analyzed. Degree of overweight was assessed by percent overweight and standard deviation score-body mass index.The age (mean +/- SD) of the 259 patients recruited (121 boys and 138 girls) was 11.9 +/- 2.1 yr at diagnosis and 14.4 +/- 2.0 yr at the time of the survey. Sixty-nine percent of all patients were obese (percent overweight >or=20%) at the time of diagnosis. Obese patients were older at the time of diagnosis and had a higher level of hemoglobin A1c (HbA1c) at diagnosis than non-obese patients (p < 0.05), and there were fewer girls than boys. Twenty two (11.3%) of 195 patients had low birth weights (or=4000 g). The frequencies of low and high birth weights were higher among patients with T2DM than among a control group, producing a U-shaped distribution (p < 0.05). The frequency of a family history of diabetes was lower among low-birth weight patients. In contrast, high-birth weight patients had a higher prevalence of diabetic mothers and medication including insulin therapy (p < 0.05).Obesity was shown to be a major risk factor for childhood-onset T2DM in Japan. The frequencies of low and high birth weights were higher among patients with T2DM, and differences in clinical characteristics, such as family history of diabetes, were recognized among patients with T2DM with low, normal, and high birth weights.