Twenty‐year trend of increasing obesity in young patients with poorly controlled type 2 diabetes at first diagnosis in urban Japan

AIMS/INTRODUCTION: To investigate trends over the past 20 years for the prevalence of obesity and glycemic control in association with a patient's first hospital visit for type 2 diabetes mellitus. MATERIALS AND METHODS: This was a historical, cross‐sectional, time‐series, single‐center study carried out at Marunouchi Hospital. Data from type 2 diabetic patients who were never treated until their first hospital visit were analyzed for the following periods: 1986–1987 (group A, n = 453), 1996–1997 (group B, n = 547) and 2006–2008 (group C, n = 443). Data on each patient's body mass index (BMI), age, untreated duration and glycated hemoglobin levels were also collected. RESULTS: Obesity in younger patients (below age 40 years and ages 40–49 years in group C) with poor glycemic control increased over time. Patients with a BMI of <21.0 kg/m(2) or ≥23.0 kg/m(2) showed worse glycemic control than those with a BMI of 21.0–23.0 kg/m(2) in group C. Younger patients had worse glycemic control and shorter untreated durations in group C. A BMI ≥23.0 kg/m(2) was an independent risk factor for glycated hemoglobin levels ≥8.4% in group C, even after correction for sex, age, untreated duration and symptoms. CONCLUSIONS: In recent years, glycemic control has worsened in young, obese patients in urban Japan. Obesity is rapidly increasing in younger patients, and patients with a BMI ≥23.0 kg/m(2) might be candidates for diabetes screening. This trial was registered with the University Medical Information Network Clinical Trials Registry (no. UMIN000005725).