Interaction between 25-hydroxyvitamin D and variants at 17q12-21 on respiratory infections

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

Prenatal vitamin D status and respiratory and allergic outcomes in childhood: A meta-analysis of observational studies

BACKGROUND

Prenatal vitamin D status may influence offspring's respiratory and allergic outcomes; however, evidence is inconclusive. A systematic review and meta-analysis were conducted on the association between 25-hydroxyvitamin D [25(OH)D] levels in maternal blood in pregnancy or cord blood at birth with the risk of offspring's respiratory and allergic conditions.

METHODS

Two independent researchers conducted systematic searches for observational studies published until May 2017 using defined keywords on vitamin D and health outcomes, including respiratory tract infections (RTIs), wheeze, asthma, atopic eczema, allergic rhinitis, allergic sensitization, and lung function. Random-effects meta-analyses were conducted.

RESULTS

A total of 34 from 547 retrieved articles were included. Increased prenatal exposure to 25(OH)D was inversely associated with risk of RTIs. Comparing the highest with the lowest category of 25(OH)D levels, the pooled odds ratio was 0.64 (95% CI 0.47, 0.87). A positive borderline association was found for lung function at school age (FEV1 z-score coefficient 0.07, 95% CI -0.01, 0.15). No associations were found for wheeze, asthma, atopic eczema, allergic rhinitis, and allergic sensitization.

CONCLUSION

The introduction of public health measures to tackle vitamin D status in pregnancy may reduce the burden of RTIs in offspring. Current evidence does not support an impact on asthma and allergy.

Pediatric pulmonology year in review 2016: Part 2

Pediatric Pulmonology continues to publish research and clinical topics related to the entire range of children's respiratory disorders. As we have done annually in recent years, we here summarize some of the past year's publications in our major topic areas, as well as selected literature in these areas from other core journals relevant to our discipline. This review (Part 2) covers selected articles on neonatology, asthma, physiology and lung function testing, and infectious diseases.

Infant Respiratory Tract Infections or Wheeze and Maternal Vitamin D in Pregnancy: A Systematic Review

BACKGROUNDS

Respiratory tract infections (RTIs) are a common cause of morbidity and mortality in young children and can be associated with wheeze. Vitamin D can have a protective role against RTI.

MATERIALS AND METHODS

A systematic search of PubMed, Embase and the Cochrane library was performed. Titles and abstracts were evaluated, and selected articles were reviewed by 2 authors. We included randomized controlled trials (RCTs) investigating the effect of vitamin D supplementation during pregnancy on RTIs or wheeze in children of 5 years of age or younger. Observational studies on the association between serum 25-hydroxyvitamin D during pregnancy, or at birth, and RTIs and/or wheeze were included. The protocol was registered on PROSPERO (Registration number: CRD42015019183).

RESULTS

Of 4 RCTs, 1 showed a protective effect of a high daily dose (2000 IU) of vitamin D during pregnancy on offspring RTI doctor visits (P = 0.004; the RCT also included 800 IU/d supplement to the infants until 6 months). Meta-analysis of 3 RCTs showed a reduced relative risk for offspring wheeze when mothers were supplemented with vitamin D during pregnancy [relative risk: 0.81 (95% confidence interval: 0.68-0.97), P = 0.025]. In 3 of 4 strong-quality, and 5 of 10 moderate-quality observational studies, an inverse association between pregnancy and cord 25-hydroxyvitamin D and subsequent wheeze and/or RTI was seen.

CONCLUSION

Growing evidence supports a preventive role of vitamin D during pregnancy on offspring wheeze and/or RTI. Recommendations in future intervention studies may need to exceed current recommendations of vitamin D supplementation during pregnancy to show benefit against childhood wheeze or infections.