摘要Background:Type 2 diabetes mellitus (T2DM) has traditionally been considered to affect mainly the elderly;however,the age at diagnosis has gradually reduced in recent years.Although the incidence of young-onset T2DM is increasing,it is still not fully clear the onset characteristics and risk factors of early-onset T2DM.The aim of this study was to describe the initiating characteristics of early-onset T2DM in Chinese patients and evaluate the risk factors for diabetes mellitus.Methods:This cross-sectional controlled study was performed using a questionnaire survey method in outpatients of multiple centers in China.A total of 1545 patients with T2DM with an age at onset of＜40 years were included,and the control group consisted of subjects aged ＜40 years with normal blood glucose level.Results:In patients with young-onset T2DM,the mean age and initial hemoglobin 1Ac at diagnosis were 32.96 ± 5.40 years and 9.59 ± 2.71％,respectively.Most of the patients were obese,followed irregular diet pattern and sedentary lifestyle,had life or work pressure,and had a family history of diabetes mellitus.Compared with subjects with normal blood glucose level,logistic regression analysis showed that waist-to-hip ratio (odds ratio [OR] 446.99,95％ confidence interval [CI] 42.37-4714.87),family history of diabetes mellitus (OR 23.46,CI14.47-38.03),dyslipidemia (OR 2.65,CI 1.54-4.56),diastolic blood pressure (OR 1.02,CI 1.00-1.04),and body mass index (OR 0.95,CI 0.92-0.99) are independent factors for early-onset T2DM.Conclusions:We observed that abdominal obesity,family history of diabetes mellitus,and medical history of hypertension and dyslipidemia are independent risk factors for early-onset T2DM.It is,therefore,necessary to apply early lifestyle intervention in young people with risk of diabetes mellitus.