Long-term glycemic control influences the onset of limited joint mobility in type 1 diabetes

Background: Limited joint mobility (LJM) in childhood insulin-dependent (type 1) diabetes is associated with a substantially increased risk of microvascular complications. Cross-sectional studies have not demonstrated a relationship between LJM and metabolic control. This study was designed to determine whether glycemic control, as measured by glycohemoglobin (hgbA(1C)) levels from the onset of diabetes, is associated with the occurrence of LJM. Method: Probands (n = 18) had hgbA(1C) values and recorded observation of joint function from soon after onset of their diabetes. Controls (n = 40) were matched to probands for gender and age at diagnosis and had follow-up beyond the age at which the proband was found to have LJM. Results: The odds ratio for occurrence of LJM for the mean hgbA(1C) from diabetes onset was 1.46, 95% confidence limits 1.07 to 2.00. Thus, for every unit increase in average hgbA(1C) there was approximately a 46% increase in the risk of LJM. When hgbA(1C) was dichotomized, the OR for hgbA(1C) of more than 8% was 2.55, and the OR was 4.54 if the hgbA(1C) was greater than 12%. Age at diagnosis and duration of diabetes were not independent prognostic factors for LJM.