Association of vitamin D levels and asthma exacerbations in children and adolescents: Experience from a tertiary care center

Molecular Insight into the Role of Vitamin D in Immune-Mediated Inflammatory Diseases

In the last decades, it has become increasingly evident that the role of vitamin D extends beyond the regulation of calcium homeostasis and the maintenance of bone health. A significant extraskeletal function of vitamin D is its role in modulating the immune system, particularly highlighted in the context of immune-mediated inflammatory diseases, where correlations between vitamin D status and genetic variations in the vitamin D receptor have been observed about the incidence and severity of these conditions. Additionally, different studies have reported the existence of immunomodulatory effects of vitamin D, particularly the effects of vitamin D on dendritic cell function, maturation, cytokine production, and antigen presentation, and that its deficiency may be associated with a sub-inflammatory state. In this sense, different clinical trials have been conducted to assess the therapeutic efficacy of vitamin D in different immune-mediated inflammatory disorders, including asthma, atopic dermatitis (AD), rheumatoid arthritis (RA), psoriasis, thyroid diseases, infectious diseases, and systemic lupus erythematosus (SLE). This review will provide a comprehensive overview of the current understanding of the molecular mechanisms underlying vitamin D's immunomodulatory properties, its role, and innovative therapeutic applications in patients with immune-mediated inflammatory diseases.

The role of vitamin D deficiency in the development of paediatric diseases

Children's Vitamin D (VitD) fortification and supplementation are diminishing due to less outdoor exercise and insufficient VitD intake (low exogenous intake and endogenous malabsorption induced by gastrointestinal disease). Consequently, children in many developed countries suffer from VitD deficiency, which may contribute to many paediatric disorders. Our review briefly introduced the metabolic process of VitD, summarized the role of VitD in paediatric diseases such as autism, obesity, rickets and asthma. We sought to identify the link between VitD deficiency and these diseases.

Asthma exacerbations and body mass index in children and adolescents: experience from a tertiary care center

The prevalence and incidence of asthma continue to rise globally. Obesity has been identified as a potential risk factor for asthma exacerbations. The association between body mass index (BMI) and asthma is not well studied in some regions. This study aims to investigate the impact of BMI on pediatric asthmatic patients. This retrospective study was conducted at the Aga Khan University Hospital from 2019 to 2022. Children and adolescents with asthma exacerbations were included. The patients were classified into four groups based on their BMI: underweight, healthy weight, overweight, and obese. The demographic characteristics, medications used, predicted forced expiratory volume in 1 second (FEV1) measurements, asthma exacerbations per year, length of stay per admission, and the number of patients requiring high dependency unit (HDU) care were recorded and analyzed. Our results demonstrated that patients in the healthy weight category had the highest percentage of FEV1 (91.46±8.58) and FEV1/forced vital capacity (FVC) (85.75±9.23) (p<0.001). The study found a significant difference in the average number of asthma exacerbations per year between the four groups. Obese patients had the highest number of episodes (3.22±0.94), followed by the underweight group (2.42±0.59) (p<0.01). The length of stay per admission was significantly shorter for patients with a healthy weight (2.0±0.81), and there was a statistically significant difference observed in the number of patients requiring HDU care among the four groups, as well as in the average length of stay at the HDU (p<0.001). Elevated BMI is related to an increased number of annual asthma exacerbations, a low FEV1 and FEV1/FVC, an increased length of stay at admission, and an increased stay in the HDU.

Stunting as a Risk Factor for Asthma: The Role of Vitamin D, Leptin, IL-4, and CD23+

Stunting, which results from chronic malnutrition, is common in children from low- and middle-income countries. Several studies have reported an association between obesity and asthma. However, only a handful of studies have identified stunting as a significant risk factor for wheezing, a symptom of asthma, although the underlying mechanism remains unclear. This article aimed to review possible mechanisms underlying asthma in stunted children. Overall, changes in diet or nutritional status and deficiencies in certain nutrients, such as vitamin D, can increase the risk of developing asthma. Vitamin D deficiency can cause linear growth disorders such as stunting in children, with lower levels of 25(OH)D found in underweight and stunted children. Stunted children show a decreased lean body mass, which affects lung growth and function. Low leptin levels during undernutrition cause a Th1–Th2 imbalance toward Th2, resulting in increased interleukin (IL)-4 cytokine production and total immunoglobulin E (IgE). Studies in stunted underweight children have also found an increase in the proportion of the total number of B cells with low-affinity IgE receptors (CD23+). CD23+ plays an important role in allergen presentation that is facilitated by IgE to T cells and strongly activates allergen-specific T cells and the secretion of Th2-driving cytokines. Stunted children present with low vitamin D and leptin levels, impaired lung growth, decreased lung function, and increased IL-4 and CD23+ levels. All of these factors may be considered consequential in asthma in stunted children.