[Low bone mineral density in children with Crohn's disease]

Risk of diagnosed fractures in children with inflammatory bowel diseases

BACKGROUND

Decreased bone mass is common in children with inflammatory bowel disease (IBD); however, fracture risk is unknown. We sought to evaluate fracture risk in children with IBD as compared to unaffected controls and determine whether this risk is affected by geographical region (a proxy for sun/vitamin D exposure) and oral steroid use.

METHODS

We identified cases of Crohn's disease (CD) and ulcerative colitis (UC), less than 20 years of age, using administrative data from 87 health plans. Each case was matched to three controls on the basis of age, gender, and geographical region. We identified fractures in cases and controls using ICD-9 diagnosis codes and measured oral steroid exposure using NDC codes.

RESULTS

The study included 733 children with CD, 488 with UC, and 3287 controls (mean age 15 years). IBD was not associated with a higher risk of fracture at any site (CD odds ratio [OR] 0.8, 95% confidence interval [CI] 0.6-1.1; UC OR 1.4, 95% CI 1.0-2.1) or at multiple sites (CD OR 0.8, 95% CI 0.4-1.7; UC OR 0.4, 95% CI 0.1-1.4). Among IBD patients we did not identify any significant differences in the fracture rate between those residing in the Northeast/Midwest versus the South (OR 1.3, 95% CI 0.8-2.2). Steroid exposure was not associated with the occurrence of fractures (P = 0.6).

CONCLUSIONS

Children with IBD are no more likely to have experienced a diagnosed fracture than age-, sex-, and gender-matched controls.

Longitudinal study of bone mineral density in children after a diagnosis of Crohn's disease

AIM

The purpose of this study was to measure the bone mineral density (BMD) of children with Crohn's disease (CD) and to prospectively assess its evolution.

PATIENTS AND METHODS

A total of 27 children (20 boys, seven girls), aged 12.1±2.5 years, were recruited at the time of CD diagnosis. Dual-energy X-ray absorptiometry (DEXA) was used to measure BMD, expressed as Z scores for chronological age (BMD/CA) and bone age (BMD/BA). One year later, BMD was measured again to identify any correlations with disease activity [group A (active disease) vs group R (remission)].

RESULTS

BMD/CA and BMD/BA were negatively correlated with delay in diagnosis (P<0.0001 and P<0.05, respectively). BMD/CA was less than -2 standard deviation (SD) in nine patients and BMD/BA was less -2 SD in four patients. At the follow-up, the increase in BMD was smaller in group A (n=14), whether expressed as absolute values (-0.002 vs 0.040 g/cm(2) per year; P<0.024) or as percentages (-0.2 vs 6.6%; P<0.041); changes in BMD/CA (-0.5 vs -0.1 SD/year) and BMD/BA (-0.3 vs 0 SD/year) did not differ.

CONCLUSION

Diagnostic delay greatly affects BMD in children with CD even prior to corticosteroid therapy. The risk of low BMD increases with persistent CD activity, although the risk is reduced in association with bone maturation delay.

Nutritional considerations in pediatric inflammatory bowel disease

Nutrition is a critical part of the management of inflammatory bowel disease (IBD) in children and adults. Malnutrition and micronutrient deficiencies are common at the time of diagnosis and may persist throughout the course of the disease. There are a number of similarities with regards to the nutritional complications and the approach to nutritional management in IBD in both children and adults, but there are also important differences. Growth failure, pubertal delay and the need for corticosteroid-sparing regimens are of higher importance in pediatrics. In the pediatric population, exclusive enteral nutrition may be equivalent to corticosteroids in inducing remission in acute Crohn's disease, and may have benefits over corticosteroids in children. Adherence with exclusive enteral nutrition is better in children than in adults. Iron deficiency anemia is an important problem for adults and children with IBD. Intravenous iron administration may be superior to oral iron supplementation. Ensuring adequate bone health is another critical component of nutritional management in IBD, but guidelines for screening and therapeutic interventions for low bone mineral density are lacking in children.

Report on the vitamin D status of adult and pediatric patients with inflammatory bowel disease and its significance for bone health and disease

Vitamin D is a hormone responsible for calcium homeostasis and essential for bone mineralization throughout the lifespan. Recent studies revealed a high prevalence of hypovitaminosis D among healthy adults and children, especially in the northern hemisphere, and a link between this condition and suboptimal bone health. Moreover, maintenance of what are today considered optimal vitamin D stores has not been achieved throughout the year with currently recommended daily intake for vitamin D. The prevalence of hypovitaminosis D is even higher among adults with inflammatory bowel disease (IBD), a situation that may be caused by malabsorption and gastrointestinal losses through an inflamed intestine, among other factors. In children with IBD, existing reports of vitamin D status are scarce. The relationship between vitamin D status and bone health, although well-established in healthy adults and children, has been controversial among adults and children with IBD, and the reasons for this have not been investigated to date. Studies in animal models of colitis and in vitro human studies support a role of vitamin D in the regulation of the immune system of the gut and the potential of vitamin D and its derivatives as therapeutic adjuncts in the treatment of IBD. This role of vitamin D has not been investigated with translational studies to date. Currently, there are no guidelines for monitoring vitamin D status, treating hypovitaminosis D, and maintaining optimal vitamin D stores in patients with IBD. These tasks may prove particularly difficult because of malabsorption and gastrointestinal losses that are associated with IBD.

Vitamin D status in children and young adults with inflammatory bowel disease

OBJECTIVES

Previous studies of vitamin D status in pediatric patients with inflammatory bowel disease have revealed conflicting results. We sought to report (1) the prevalence of vitamin D deficiency (serum 25-hydroxy-vitamin D concentration < or = 15 ng/mL) in a large population with inflammatory bowel disease, (2) factors predisposing to this problem, and (3) its relationship to bone health and serum parathyroid hormone concentration.

PATIENTS AND METHODS

A total of 130 patients (8-22 years of age) with inflammatory bowel disease, 94 with Crohn disease and 36 with ulcerative colitis, had serum 25-hydroxy-vitamin D, intact parathyroid hormone, and lumbar spine bone mineral density (using dual-energy x-ray absorptiometry) measured at Children's Hospital Boston.

RESULTS

The prevalence of vitamin D deficiency was 34.6%. Mean serum 25-hydroxy-vitamin D concentration was similar in patients with Crohn disease and ulcerative colitis, 52.6% lower among patients with dark skin complexion, 33.4% lower during the winter months (December 22 to March 21), and 31.5% higher among patients who were taking vitamin D supplements. Serum 25-hydroxy-vitamin D concentration was positively correlated with weight and BMI z score, disease duration, and serum albumin concentration and negatively correlated with erythrocyte sedimentation rate. Patients with Crohn disease and upper gastrointestinal tract involvement were more likely to be vitamin D deficient than those without it. Serum 25-hydroxy-vitamin concentration was not associated with lumbar spine bone mineral density z score or serum parathyroid hormone concentration.

CONCLUSIONS

Vitamin D deficiency is highly prevalent among pediatric patients with inflammatory bowel disease. Factors predisposing to the problem include having a dark-skin complexion, winter season, lack of vitamin D supplementation, early stage of disease, more severe disease, and upper gastrointestinal tract involvement in patients with Crohn disease. The long-term significance of hypovitaminosis D for this population is unknown at present and merits additional study.

Calcium supplementation for improving bone mineral density in children

BACKGROUND

Clinical trials have shown that calcium supplementation in children can increase bone mineral density (BMD) although this effect may not be maintained. There has been no quantitative systematic review of this intervention.

OBJECTIVES

. To determine the effectiveness of calcium supplementation for improving BMD in children. . To determine if any effect varies by sex, pubertal stage, ethnicity or level of physical activity, and if any effect persists after supplementation is ceased.

SEARCH STRATEGY

We searched CENTRAL, (Cochrane Central Register of Controlled Trials) (Issue 3, 2005), MEDLINE (1966 to 1 April 2005), EMBASE (1980 to 1 April 2005), CINAHL (1982 to 1 April 2005), AMED (1985 to 1 April 2005), MANTIS (1880 to 1 April 2005) ISI Web of Science (1945 to 1 April 2005), Food Science and Technology Abstracts (1969 to 1 April 2005) and Human Nutrition (1982 to 1 April 2005). Conference abstract books (Osteoporosis International, Journal of Bone and Mineral Research) were hand-searched.

SELECTION CRITERIA

Randomised controlled trials of calcium supplementation (including by food sources) compared with placebo, with a treatment period of at least 3 months in children without co-existent medical conditions affecting bone metabolism. Outcomes had to include areal or volumetric BMD, bone mineral content (BMC), or in the case of studies using quantitative ultrasound, broadband ultrasound attenuation and ultrasonic speed of sound, measured after at least 6 months of follow-up.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data including adverse events. We contacted study authors for additional information.

MAIN RESULTS

The 19 trials included 2859 participants, of which 1367 were randomised to supplementation and 1426 to placebo. There was no heterogeneity in the results of the main effects analyses to suggest that the studies were not comparable. There was no effect of calcium supplementation on femoral neck or lumbar spine BMD. There was a small effect on total body BMC (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). Only the effect in the upper limb persisted after supplementation ceased (SMD+0.14, 95%CI+0.01, +0.28). This effect is approximately equivalent to a 1.7% greater increase in supplemented groups, which at best would reduce absolute fracture risk in children by 0.1-0.2%per annum. There was no evidence of effect modification by baseline calcium intake, sex, ethnicity, physical activity or pubertal stage. Adverse events were reported infrequently and were minor.

AUTHORS' CONCLUSIONS

While there is a small effect of calcium supplementation in the upper limb, the increase in BMD which results is unlikely to result in a clinically significant decrease in fracture risk. The results do not support the use of calcium supplementation in healthy children as a public health intervention. These results cannot be extrapolated to children with medical conditions affecting bone metabolism.