Limited joint mobility in childhood diabetes: discovery, description, and decline.

CONTEXT: The discovery of limited joint mobility (LJM) as the earliest clinically apparent complication of diabetes in children and adolescents nearly 40 years ago provided insights into the mechanism of diabetes complications. RESULTS: LJM, due to periarticular connective tissue thickening and stiffness, varied from single joint involvement bilaterally to obvious hand deformity and limitation of movement of the spine. Thick, tight, waxy skin was apparent with more severe changes; biopsy indicated thickening of the dermis and epidermis with accumulation of collagen and loss of skin appendages. Substantial growth impairment was associated with all levels of LJM. Risk for microvascular disease over a 16-year period was actuarially increased nearly 4-fold by the presence of LJM. Long-term glycemic control influenced the onset of LJM; for every unit increase in average glycated hemoglobin from onset there was a 46% increase in the risk of LJM. Between 1976-78 and 1998, the prevalence of LJM decreased from 30 to 7%, and the portion with moderate to severe changes decreased from 33 to 14%, with the disappearance of severely affected individuals. Furthermore, growth data markedly improved for those with and without LJM; 30% without LJM and 77% with LJM had been less than the 25th percentile for height, whereas the more contemporary group had 22% without LJM and 33% with LJM in this quartile. CONCLUSIONS: The elucidation of LJM as a novel and informative early complication of pediatric diabetes has provided insights into the evolution of the severe long-term complications of diabetes. The marked decrease in the frequency of LJM and statural deficit in children and youth with diabetes in the 20 years between the late 1970s and 1990s can be attributed to improved metabolic control of children and adolescents. The prevalence of LJM in a population may serve as a measure of quality of diabetes control.