Impaired skin blood flow response to heat in children with insulin dependent diabetes

Vascular disease is a major problem affecting adults with type 1 insulin-dependent diabetes mellitus. Vascular damage may occur early in the disease but the time at which this occurs is not known. We have shown previously that markers of endothelial and white blood cell function are abnormal in young people with diabetes mellitus before clinical evidence of vascular disease is apparent. This paper evaluates blood flow responses in this group (skin blood cell flux (SBCF)). We have compared vascular responses in 21 young children with diabetes (10-14 years) and matched 21 young controls (12-15 years). SBCF was measured at the dorsum of the foot by laser Doppler flowmetry and expressed in volts. The blood flow response to local heating to 44°C was assessed. Comparisons between groups were made using nonparametric statistical analyses. Results are expressed as medians and interquartile range. Basal SBCF was significantly lower in young diabetics than in young control subjects [1.3 (0.9-1.5) volts c.f. 1.8 (1.5-3.0) volts,p <0.01, respectively] as was the maximum SBCF response to 44°C [7.0 (5.0-9.0) volts c.f. 10.6 (9.5-12.6) volts,p <0.01 in diabetic and control children, respectively]. These results suggest that vascular responsiveness may be abnormal in children with diabetes mellitus well before there is clinical evidence of vascular disease.