In France, only the fasting blood glucose (FBG) measurement is recommended for diabetes screening. Ethnic heterogeneity and genetic polymorphisms specific to the Afro-Caribbean and Indo-Caribbean population in Guadeloupe justify the interest to early screen type 2 diabetes mellitus (T2DM). Our main objective is to estimate the prevalence of T2DM defined by oral glucose tolerance (OGTT) in subjects with risk factors for T2DM and not diagnosed with the FBG.

Contrary to the French recommendations, the American recommendations for the diagnosis of T2DM, include FBG, HbA1c or OGTT. These recommendations suggest that there are differences in the HbA1c levels between subjects of African origin and Caucasian subjects. The population in Guadeloupe is characterized by ethnic heterogeneity with genetic polymorphisms specific to the subjects of African and Indian origin that could justify the interest of a targeted and early screening of T2DM by another test than FBG. The main dilemma is how to confirm that subjects with risk factors of T2DM but normal FBG are not diabetic? Some of them have normal FBG levels but HbA1c levels between 5.7 and 6.4% that are not used as diagnostic criteria in France. We think that OGTT could help to better diagnose T2DM in such subjects.

After identifying these subjects, an OGTT will be performed after inclusion. The diagnosis of T2DM will be confirmed in subjects who exceeded the glucose threshold of 11mmol/L (200mg/dL), 2 hours after the OGTT.

The number of these diabetic subjects is evaluated to 10%, they will be treated according to the HAS recommendations and monitored during the year of the study. The other subjects without abnormalities will be followed at 12 months with OGTT repetition.

o Inclusion criteria : Adult subject (over 18 years and under 65 years old) Subjects of African or Indian origin and self-declared Normal FBG levels (110mg/dL) HbA1c levels between 5.7 and 6.4% One or more of the following factors: BMI > 25 kg/m2, family history of T2DM in the 1st and 2nd familial degree, hypertension, dyslipidemia.

Affiliation to the national social health system or equivalent Informed and written consent signed by the patient and the investigator (at the latest on the day of inclusion and before the completion of any research related exam)

o Exclusion criteria : Pregnant or lactating woman Women with a history of gestational diabetes Polycystic ovary syndrome Endocrine, hepatic or renal diseases affecting glycemic control Treatment that affect the metabolism of glucose or insulin Refusal to participate Subjects without adequate or impaired decisional abilities for consent to research and placed under guardianship, curatorship or safeguard of justice, person participating in another research including an exclusion period still in progress, severely impaired physical and / or psychological health, which, according to the investigator, may affect the compliance of the study participant