THE RELATION OF HAND SKIN-FOLD THICKNESS TO BONE-MINERAL DENSITY IN PATIENTS WITH CROHNS-DISEASE

Objectives: In healthy postmenopausal women, the association of skin-f old thickness (SFT) with bone mineral density (BMD) is well described, and a low SFT is a useful predictor of osteoporosis. In this study th e association between hand SFT and BMD in patients with Crohn's diseas e was assessed; and the potential for hand SFT as a screening test for osteoporosis evaluated. Design/methods: In a cross-sectional study, B MD was measured at the hip and lumbar spine by dual energy x-ray absor ptiometry (DEXA). SFT was measured on the dorsum of the right hand usi ng Holtain Tanner Whitehouse calipers. One hundred and seventeen patie nts (48 male) with Crohn's disease and 50 (25 male) controls were stud ied. Results: There was a significant correlation between hand SFT and BMD (expressed as t scores) at all four measured sites (lumbar spine r = 0.41, P< 0.0001, 95% CI 0.25-0.55, Ward's triangle r = 0.38, P< 0. 0001, 95% Cl 0.21-0.53, trochanter r = 0.33, P< 0.0001, 95% Cl 0.16-0. 48, femoral neck r = 0.38, P< 0.0001, 95% Cl 0.21-0.53). On stepwise r egression analysis, the association remained significant after correct ing for age, weight, menstrual status and current steroid use (P< 0.05 ). Hand SFT was significantly lower in patients with Crohn's disease t han controls (difference in means 0.51 mm, 95% Cl 0.3-0.72, P< 0.0001) . Mean hand SFT was significantly lower in patients with osteoporosis compared to patients with normal BMD (difference in means 0.74 mm, 95% Cl 0.33-1.15, P< 0.001), as was that of osteopenic patients compared to patients with normal BMD (difference in means 0.28 mm, 95% Cl 0.01- 0.55, P< 0.05). In the diagnosis of osteoporosis, the sensitivity of h and SFT ranged from 29% to 93%, with specificities of 54% to 95%. Conc lusions: Hand SFT is independently associated with BMD in Crohn's dise ase and is lower than in age-matched healthy subjects. Hand SFT in com bination with other easily measurable confounding variables might be u seful in screening for osteoporosis in patients with Crohn's disease.