The association between indoor air pollution and inflammation in children – A scoping review

Indoor air pollutants (IAPs) significantly contribute to the global heath burden for children, in part due to their underdeveloped physiological systems. Despite the growing evidence of the health impacts of IAPs, the association between IAP and biomarkers of inflammation, which is involved in several disease processes, remains underexplored. The main objective of this scoping review is therefore to identify, evaluate, and summarize the current body of literature on the association between IAP exposures and biomarkers of inflammation among children. Additionally, this review examines the extent to which identified studies have explored the potential role of diet, nutrition, or weight status in modifying this relationship. A scoping review of the literature was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews) guidelines. Studies published in the last 20 years and that measured IAPs and inflammatory biomarkers in children under 18 years of age were included. In total, 22 studies met the inclusion criteria. Most of these studies indicated positive associations between IAPs, including particulate matter and nitrogen dioxide, and inflammatory biomarkers such as fraction exhaled of nitric oxide (FeNO), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6). While some studies suggested the potential modifying role of nutrition and weight status, and the findings suggests that anti-inflammatory nutrients such as omega-fatty acids can mitigate inflammation, whereas pro-inflammatory nutrients may exacerbate IAP-related inflammation, the evidence remains limited. Further research is needed to explore these relationships and their long-term health consequences.