Risk factors for low bone mineral density in children and adolescents with inflammatory bowel disease.
OBJECTIVE
To evaluate bone mineral density of the lumbar spine in children and adolescents with inflammatory bowel disease, and to identify the clinical risk factors associated with low bone mineral density.


METHODS
Bone mineral density of the lumbar spine was evaluated using dual-energy X-ray absorptiometry (DXA) in 40 patients with inflammatory bowel disease. Patients were 11.8 (SD = 4.1) years old and most of them were male (52.5%). Multiple linear regression analysis was performed to identify potential associations between bone mineral density Z-score and age, height-for-age Z-score, BMI Z-score, cumulative corticosteroid dose in milligrams and in milligrams per kilogram, disease duration, number of relapses, and calcium intake according to the dietary reference intake.


RESULTS
Low bone mineral density (Z-score bellow -2) was observed in 25% of patients. Patients with Crohn's disease and ulcerative colitis had equivalent prevalence of low bone mineral density. Multiple linear regression models demonstrated that height-for-age Z-score, BMI Z-score, and cumulative corticosteroid dose in mg had independent effects on BMD, respectively, beta = 0.492 (P = 0.000), beta = 0.460 (P = 0.001), beta = - 0.014 (P = 0.000), and these effects remained significant after adjustments for disease duration, respectively, beta = 0.489 (P = 0.013), beta = 0.467 (P = 0.001), and beta = - 0.005 (P = 0.015). The model accounted for 54.6% of the variability of the BMD Z-score (adjusted R2 = 0.546).


CONCLUSIONS
The prevalence of low bone mineral density in children and adolescents with inflammatory bowel disease is considerably high and independent risk factors associated with bone mineral density are corticosteroid cumulative dose in milligrams, height-for-age Z-score, and BMI Z-score.
Lopes
Letícia Helena Caldas
LH
Division of Pediatric Gastroenterology, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, Brazil.
Sdepanian
Vera Lucia
VL
Szejnfeld
Vera Lúcia
VL
de Morais
Mauro Batista
MB
Fagundes-Neto
Ulysses
U
D015502:Absorptiometry, Photon; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D001827:Body Height; D015992:Body Mass Index; D015519:Bone Density / Q000187:drug effects / Q000502:physiology*; D001938:Brazil / Q000453:epidemiology; D002118:Calcium / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology*; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D010024:Osteoporosis / Q000453:epidemiology* / Q000503:physiopathology*; D015995:Prevalence; D012307:Risk Factors
D000305:Adrenal Cortex Hormones; D002118:Calcium