Nocturnal activity of 11β-hydroxy steroid dehydrogenase type 1 is increased in type 1 diabetic children. 
The objective of this study was to investigate low-grade inflammation in children with type 1 diabetes (T1D) and its association with cortisol levels as well as its bioavailability through 11β-hydroxy steroid dehydrogenase type 1 (11β-HSD1) activity.  Children with T1D (n=45) and their non-diabetic siblings (n=28) participated in the study.  Interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRPhs) were measured between 1400 and 1800h.  Glucocorticoid metabolites were measured in the first morning urine on clinic day and 11β-HSD1 activity was estimated by tetrahydrocortisol/tetrahydrocortisone (THF/THE) ratio.  Diabetic patients presented with an increased THF/THE ratio compared with controls (median: 0.68 [range: 0.45-1.18] vs 0.45 [0.27-0.98], respectively; P<10(-3)).  There was no difference between diabetic patients and controls for IL-6 (0.6ng/mL [0.6-6.8] vs 0.6 [0.6-2.2], respectively; P=0.43) and CRPhs (0.4mg/L [0-7.4] vs 0.3 [0-8.2]; P=0.26, respectively).  When adjusted for age, gender and BMI, the THF/THE ratio was significantly associated with CRPhs (β=0.32, P=0.02) in diabetic patients, but not in controls.  Low-grade inflammation assessed by plasma CRPhs and IL-6 concentrations was not detectable in our cohort of T1D children.  Nocturnal 11β-HSD1 activity was increased and associated with plasma CRPhs concentration in diabetic patients.  These results may be explained by either a direct or inflammation-mediated effect of the relative hepatic lack of insulin due to subcutaneous insulin therapy.