Objective To explore the relationship between glycated haemoglobin A1C (HbA1C) and subclinical atherosclerosis as assessed by carotid intima-media thickness (cIMT) in Chinese Han obese children and adolescents without diabetes.

Methods A total of 524 obese children and adolescents without diabetes were analysed. All participants underwent HbA1C measurements, oral glucose tolerance tests and ultrasound measurements of cIMT. The logistic regression models were implemented to evaluate the adjusted OR of HbA1C for increased cIMT.

Results In obese boys, HbA1C was associated with increased cIMT independently of age, measurements of anthropometry, blood pressure, plasma lipid and lipoprotein, fasting plasma glucose, 2 h postchallenge glucose, uric acid and hepatic function. After adjustment for all these risk factors, the OR of increased cIMT for every 1% (11 mmol/mol) increase in HbA1C was 2.702 (95% CI 1.640 to 4.452). However, in girls, the major risk factor independently associated with cIMT was measurement of abdominal obesity instead of HbA1C.

Conclusions Our research suggests that the adoption of HbA1C as a diagnostic criterion of prediabetes and diabetes in obese boys may help to identify early macrovascular complications.