Clinical features of normal weight Japanese patients with type 2 diabetes who had formerly been obese.

AIM: Although the mean body mass index (BMI) of Japanese patients with type 2 diabetes was within the normal range, we have previously shown that approximately half of all patients classified as normal weight had been formerly obese. The present study examined the clinical features of Japanese type 2 diabetic patients who are currently of normal weight but had formerly been obese (NWFO).
METHODS: Body weight history with selfreported body weight was obtainable for 108 of 114 type 2 diabetic outpatients who had been regularly attending our department. Common carotid artery intimamedia thickness (IMT) was also measured.
RESULTS: At the time of the examinations, 5 (5%) and 36 (33%) of 108 type 2 diabetic patients were lean (BMI <18.5 kg/m(2)) and obese (BMI ≥25 kg/m(2)), respectively, whereas normal weight (BMI ≥18.5-<25 kg/m(2)) was found in 67 (62%) patients. Among 108 patients, 67 (62%) were normal weight, of which 32 (48%) were formerly obese (NWFO). NWFO patients with a mean age of 65 years old at the clinic visit had reached their lifetime maximum body weight at age 45 and became diabetic at age 51 years. Obese patients aged 62 years at the clinic visit became diabetic at age 50 and had reached their maximum weight at age 51 years. Diabetes duration was 11 years in patients who had never been obese. Thus, NWFO patients had been exposed to obesity-related metabolic abnormalities and/or hyperglycemia for 20 years on average whereas obese and never obese patients had been exposed for 11-12 years. Although obese patients had higher fasting TG and greater BMI than NWFO, both obese and NWFO patients had similarly lower HDL cholesterol levels than those who had never been obese; however, there was no difference among the 3 groups in diabetic treatment, diabetes duration, HbA1c levels, and prevalence of atherosclerotic risk factors, including smokers, users of statins and antihypertensive drugs. Carotid max IMT was thicker in NWFO type 2 diabetic patients (0.86±0.04 mm) than either obese patients (0.78±0.03 mm, p=0.041) or those who had never been obese (0.78±0.02 mm, p=0.046).
CONCLUSION: This report confirms that approximately half of 108 Japanese type 2 diabetic patients who are currently normal weight were formerly obese and shows that these patients had a thicker carotid IMT than either obese patients or those who had never been obese. Formerly obese diabetic patients who have lost weight and are currently normal weight might have been exposed to long-term obesity-related cardiometabolic abnormalities and/or hyperglycemia, resulting in increased common carotid IMT. We therefore suggest that an improved clinical screening tool would include the assessment of body weight history for all Japanese type 2 diabetic patients at their first clinic visit.