Juvenile onset of Crohn's disease: A risk factor for reduced lumbar bone mass in premenopausal women

BACKGROUND: Crohn's disease (CD) is associated with reduced bone mass. Bone fragility is the result of both growth-related and age-related factors; thus, exposure to a chronic illness, such as CD, during skeletal growth may compromise peak bone mass. Our aim was to assess whether the onset of CD during skeletal growth had an impact on bone mass in adulthood in premenopausal women. METHODS: Adult premenopausal CD patients who had a whole body, lumbar and hip bone densitometric evaluation were selected. Information regarding age, gender, weight, duration of CD, age at diagnosis, use of glucocorticoids and disease activity during the year before densitometric assessment and laboratory parameters were collected. RESULTS: Data from 57 patients (28+/-10 years) were analyzed. Age at diagnosis was independently associated with lumbar bone mineral content (BMC). Lean mass was independently associated with total, lumbar and hip BMC. Patients with a history of onset of CD before 16 years of age (n=20) were 11.6+/-2 years old at diagnosis. They had low lumbar and hip Z scores. They had significantly lower BMC, bone mineral density and Z scores in lumbar area and both hips than those diagnosed after the age of 16. They also had significantly lower lumbar area than those diagnosed after the age of 16. CONCLUSIONS: The onset of CD during skeletal growth is a risk factor for reduced lumbar and hip bone mass in adulthood in premenopausal women.