Seasonal variability of vitamin D and bone metabolism in infliximab-treated paediatric Crohn's disease

The Role of Vitamin D in Immune System and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a nonspecific inflammatory disease that includes ulcerative colitis (UC) and Crohn’s disease (CD). The pathogenesis of IBD is not fully understood but is most reported associated with immune dysregulation, dysbacteriosis, genetic susceptibility, and environmental risk factors. Vitamin D is an essential nutrient for the human body, and it not only regulates bone metabolism but also the immune system, the intestinal microbiota and barrier. Vitamin D insufficiency is common in IBD patients, and the abnormal low levels of vitamin D are highly correlated with disease activity, treatment response, and risk of relapse of IBD. Accumulating evidence supports the protective role of vitamin D in IBD through regulating the adaptive and innate immunity, maintaining the intestinal barrier and balancing the gut microbiota. This report aims to provide a broad overview of the role vitamin D in the immune system, especially in the pathogenesis and treatment of IBD, and its possible role in predicting relapse.

A Systematic Review of Micronutrient Deficiencies in Pediatric Inflammatory Bowel Disease

BACKGROUND

This systematic review critically analyzes the current research on micronutrient deficiency in children with inflammatory bowel disease (IBD) and synthesizes these data to provide evidence-based guidelines for nutritional surveillance in this population.

METHODS

We searched 5 databases (Ovid Medline, PubMed, Scopus, CINAHL, and Cochrane Library) for studies evaluating micronutrients in patients with IBD using the following inclusion criteria: 1) original research, 2) published 1996 or later; 3) published in English; 4) human subjects; and 5) containing pediatric data. Studies were reviewed and included based on the strength of research methods. Data on the prevalence of micronutrient deficiencies in pediatric patients with IBD and risk factors for micronutrient deficiency in these patients were extracted from included studies and compared and discussed in preparation of the proposed guidelines and manuscript.

RESULTS

A total of 39 studies were included in the final review. The data presented in these studies show that iron deficiency and vitamin D deficiency are common in pediatric patients with IBD. Vitamin B12 and folate deficiency are rare. Zinc deficiency, while not common, occurs at a higher rate in patients with Crohn's disease than in healthy controls. There was limited data on vitamins A, E, and C, and selenium, but deficiency of these micronutrients seems rare.

CONCLUSIONS

We recommend annual surveillance of iron and vitamin D in pediatric patients with IBD regardless of disease activity or phenotype. Zinc should be monitored annually in patients with Crohn's disease. There is insufficient evidence to support routine screening for other micronutrient deficiencies.

Persistence of Muscle-bone Deficits Following Anti-tumour Necrosis Factor Therapy in Adolescents With Crohn Disease

OBJECTIVES

The aim of the study is to assess change in the muscle-bone unit in adolescents with Crohn disease (CD) on anti-tumour necrosis factor (anti-TNFα).

METHODS

Prospective study following anti-TNFα in 19 adolescents with CD with a median age (range) of 15.1 years (11.2, 17.2). At baseline, 6 and 12 months, subjects had a biochemical assessment of insulin growth factor axis, bone turnover and muscle-bone health by dual energy absorptiometry (DXA), peripheral quantitative computed tomography (pQCT), and dynamic isometry.

RESULTS

Significant clinical improvement in disease activity was observed by 2 weeks (P = 0.004 vs baseline) and maintained at 12 months (P = 0.038 vs baseline). Median bone specific alkaline phosphatase standard deviation score (SDS) increased from -1.7 (-3.6 to -1.0) to -1.2 (-3.6 to -0.5) by 6 weeks (P = 0.01). At baseline, DXA total body and lumbar spine bone mineral density (BMD) SDS was -0.9 (-2.3 to 0.5) and -1.1 (-2.9 to 0.4), respectively. At baseline, pQCT trabecular BMD SDS at 4% tibia and muscle cross-sectional area SDS at 66% radius was -1.6 (-3.2 to 1.1) and -2.4 (-4.3 to -0.3), respectively. At baseline, maximal isometric grip force (MIGF) of the non-dominant hand adjusted for height was -1.5 (-4.5 to 0.49). All these deficits in muscle-bone persisted at 6 and 12 months.

CONCLUSIONS

Despite improvement in disease and osteoblast activity, bone and muscle deficits, as assessed by DXA, pQCT, and grip strength in adolescents with CD did not improve following twelve months of anti-TNFα.

Associations of seasonal patterns and vitamin D levels with onset and flares of pediatric inflammatory bowel disease

BACKGROUND

As inflammatory bowel disease (IBD) might be associated with environmental factors such as seasonal patterns and low vitamin D levels we aimed to assess their association with IBD onset and flares in a large cohort of children.

METHODS

The records of 623 pediatric onset IBD patients were reviewed retrospectively including age at onset, gender, severity indices, month of first symptom, and vitamin D levels at diagnosis. For a subgroup of patients, data included date of first flare and vitamin D levels during flare and remission.

RESULTS

Median age at diagnosis was 14 years (IQR 11.66-15.58). Disease onset did not vary significantly between either month (P=0.367) or seasons (P=0.460). Vitamin D deficiency at the time of diagnosis was prevalent in 21% of patients with no significant association with month, season or disease's type. Vitamin D deficiency was significantly more prevalent in patients with malnutrition (P<0.001) and was associated with hypoalbuminemia (P=0.02) but did not correlate with low bone mineral density. Analysis of 169 first flares showed that flares were more common in June and less common in April (P=0.016). Mean vitamin D level was significantly lower during flares compared with remission (55.25±19.28 vs. 64.16±26.6, respectively, P=0.012).

CONCLUSIONS

IBD onset in school aged children is not associated with seasonal patterns whereas flares may follow a specific monthly pattern. Disease flares are associated with low vitamin D blood levels. Vitamin D deficiency is associated with malnutrition and hypoalbuminemia.