Bone density in a population-based cohort of premenopausal adult women with early onset inflammatory bowel disease

OBJECTIVE: We aimed to determine the bone mineral density (BMD) using dual energy x-ray absorptiometry in a population-based sample of women with inflammatory bowel disease who were diagnosed before age 20 yr and who are currently premenopausal and less than 45 yr. METHODS: The University of Manitoba Inflammatory Bowel Disease Epidemiology Research Registry was accessed to find eligible women. Of 171 eligible subjects, 82 agreed to participate, and 70 appeared for dual energy x-ray absorptiometry. All subjects completed demographic, clinical, and lifestyle questionnaires and underwent dual energy x-ray absorptiometry with analyses for both areal and volumetric BMD. RESULTS: The mean areal T scores at the lumbar spine, femoral neck, total hip, and total body were -0.14 +/- 1.05, -0.15 +/- 1.04, -0.25 +/- 1.17, and +0.09 +/- 1.04, respectively. Forty-five subjects had normal BMD, and 25 had a T score < -1. There were no significant differences between these groups for predictive variables. Only three (4%) had osteoporosis (T score < -2.5 at any site). There were 12 with disease onset before puberty and 58 after puberty. There were no differences between these groups for BMD. Volumetric BMD was slightly higher than areal BMD at the lumbar spine (p < 0.0002), femoral neck (p < 0.01), and total hip (p < 0.001). CONCLUSIONS: In a population-based sample of women diagnosed with IBD before 20 yr of age and who are currently premenopausal, their average BMD is normal and the prevalence of osteoporosis is very low. Despite the potential for children with IBD to develop osteoporosis, their BMD as adults is generally normal.