A first-degree relative with diabetes mellitus is an important risk factor for rural Thai villagers to develop type 2 diabetes mellitus.

The screening of 609 villagers in rural areas of northeastern Thailand resulted in the detection of 110 (18.1%) new cases of type 2 diabetes (T2DM). The diagnoses were made on the basis of a glycated hemoglobin (HbA1c) value ≤ 6.5%. Among all those screened, 243 (40%) reported having a father or mother with T2DM. Among the new cases, 66 (60%) reported a first-degree relative, predominantly their mothers, who had the disease. Together with age and the body mass index, a mother or father with DM was strong risk factor for the development of T2DM (adjusted odds ratio = 2.9, 95% confidence interval = 1.84-4.57) when compared with the absence of a first-degree relative with DM. It is concluded that family history of a first-degree relative is an important additional information that might improve the validity of the screening procedure.