BONE-DENSITY AND CALCIUM-METABOLISM IN PATIENTS WITH LONG-STANDING, QUIESCENT CROHNS-DISEASE

Objective: To assess the prevalence of metabolic bone disease associated with Crohn's disease and its possible aetiopathogenic factors. Patients: The study included 20 men with long-standing, inactive Crohn's disease of the ileum or ileo-caecum (nine not resected, 11 with surgical resections) and 12 healthy age-matched controls. Interventions: Bone density (BMD) was measured using dual X-ray absorptiometry of the lumbar spine. Calciotropic hormones, vitamin D metabolites, minerals and markers of bone turnover were determined in serum, and hydroxyproline, cyclic AMP and calcium in urine. The intestinal fractional absorption of orally administered 47 calcium was also assessed. Results: Of the patients, 30% had densitometric signs of bone demineralization (Z-score less than -2). Patients who had not undergone surgical resection had a lower lumbar spine BMD compared with controls (P<0.05). The degree of osteopenia correlated with the lifetime prednisolone dose (P<0.01). Patients who had experienced relapses of Crohn's disease in the previous year, not treated with steroids, had a significantly greater bone loss compared with those with quiescent disease. Smokers had a lower BMD than non-smokers. None of the biochemical markers were significantly altered. Conclusions: Bone demineralization is frequent in Crohn's disease. Since there is no evidence of calcium malabsorption, vitamin D deficiency or active bone disease, demineralization appears to be mainly due to steroid therapy, but inflammation may have an important contributory role.