['Here we examined whether intellectual disability is independently associated with hyperglycaemia.', 'We recruited 233 consecutive young and middle-aged adults with intellectual disability. After exclusion of subjects on medication for metabolic diseases or with severe intellectual disability (IQ < 35), 121 subjects were divided by IQ into a group with moderate intellectual disability (35 ≤ IQ ≤ 50), a mild intellectual disability group (51 ≤ IQ ≤ 70) and a borderline group (IQ > 70).', 'HbA1c level was higher in subjects with moderate intellectual disability (42 ± 9 mmol/mol; 6.0 ± 0.8%) than those in the borderline group (36 ± 4 mmol/mol; 5.5 ± 0.3%) and mild intellectual disability group (37 ± 5 mmol/mol; 5.5 ± 0.5%) groups. HbA1c level was correlated with age, BMI, blood pressure, serum triglycerides and IQ in simple linear regression analysis. Multiple regression analysis indicated that IQ, age, BMI and diastolic blood pressure were independent explanatory factors of HbA1c level.'] Is iQ an independent predictor of glycated haemoglobin level in young and middle-aged adults with intellectual disability?