Increased urinary excretion of collagen crosslinks in type 1 diabetic children in the first 5 years of disease

To analyze possible early abnormalities in bone resorption in type 1 diabet es mellitus the urinary excretion of the collagen crosslinks pyridinoline a nd deoxypyridinoline was evaluated by immunoassay in 26 prepubertal diabeti c patients (mean age 7.8 +/- 1.6 years, mean duration 3.0 +/- 1.1 years) an d 46 healthy children (age 8.3 +/- 1.3 years). Relationships with growth pa rameters (height-standard deviation score, body mass index and height veloc ity during the year preceding the study) and metabolic control were sought. Longitudinal and ponderal growth was normal in diabetic children. Urinary collagen crosslink excretion was 88.4 +/- 25 nmol/mmol creatinine (median 8 6, range 44-146) in diabetic patients and 65.6 +/- 19 nmol/mmol creatinine (median 61, range 32-108) in controls (p = 0.0002). It was positively influ enced by diabetic status (beta = 20.5) and negatively by age (beta = -6.41) , controlling by sex and BMI (p = 0.0001). A positive correlation was found between collagen crosslinks and blood glucose (r = 0.48, p = 0.01) or HbA1 c levels (r = 0.44, p = 0.02) evaluated at the time of the study, while no significant correlation was found with the mean HbA1c values assessed in th e last year or throughout the whole duration of diabetes. Collagen crosslin k excretion was significantly increased in patients who presented worsening of their metabolic control in the last 3 months. No relationship was found with the duration of disease or growth parameters. In conclusion, the elev ated urinary excretion of collagen crosslinks in diabetic children indicate s that bone resorption may be disturbed. Poor metabolic control influences the increased rate of bone resorption and may expose growing diabetic patie nts to a risk of bone loss.