Association of Intestinal Alkaline Phosphatase and vitamin D level with enteric pathogens in children: results from the MAL-ED study in Bangladesh

Objective Intestinal Alkaline Phosphatase (IAP), expressed by enterocytes, maintains gut homeostasis by promoting commensal microbiota growth and limiting inflammation. Vitamin D strengthens intestinal barrier, and its deficiency is linked to various diseases. This study explores the relationship among IAP, vitamin D, and enteric pathogens in children.

In the MAL-ED (Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development) study, 265 newborns were enrolled between February 2010 to February 2012, from Dhaka, Bangladesh. 15-month time point data was collected and analyses, where intestinal pathogens were identified by TaqMan Array Card assay, stool IAP and serum vitamin D level were determined by colorimetric assay and chemiluminescence immunoassay respectively. Multivariable linear regression was performed to determine the association between IAP, vitamin D and gut pathogens. A p-value of <0.05 is considered as significant.

Median (IQR) of IAP was 55.41 (19.60, 155.41) U/µL. Bivariate analysis showed significant negative association of IAP with Campylobacter-pan Genome (p=0.047), Campylobacter jejuni (p=0.020) and Enterocytozoon bieneusi (p=0.023). Multivariable linear regression analysis revealed a significant and inverse association with the Adenovirus-pan genome (β= -2.00; 95% CI= -3.94, -0.07) and E. bieneusi (β= -3.03; 95% CI= -5.94, -0.11).

IAP was inversely and significantly associated with Adenovirus-pan genome and E. bieneusi, a less-explored enteric pathogen, while its relationship with vitamin D was positive but not statistically significant. These findings suggest that IAP may play a protective role against specific enteric pathogens. What is already known on this topic Intestinal Alkaline Phosphatase (IAP) plays a crucial role in maintenance of gut homeostasis by promoting beneficial microbiota and reducing intestinal inflammation. Vitamin D strengthens the intestinal barrier, and deficiency has been linked to increased risk of infections and various chronic diseases. While both IAP and vitamin D are important in gut health, evidence linking them with specific enteric pathogens in human, especially in children remains limited. What this study adds This study demonstrates that IAP is inversely and significantly associated with Adenovirus-pan genome and Enterocytozoon bieneusi, a less-explored pathogen in children. It shows that although not statistically significant, IAP levels were positively related to vitamin D These findings provide novel evidence that IAP may play a protective role against specific viral and protozoan enteric infections. How this study might affect research, practice or policy The results highlight IAP as a potential biomarker of intestinal defense and a candidate for future therapeutic or preventive interventions targeting childhood enteric infections. Insights into IAP–pathogen relationships could guide in the development of microbiome-based or nutritional strategies to reduce diarrheal disease burden, and support the inclusion of IAP as potential intervention in child health and nutrition research in low-resource settings. Competing Interest Statement The authors have declared no competing interest. Funding Statement For this particular study we did not receive any grants from any funding agency in the public, commercial or not-for-profit sectors. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All procedures were carried out in accordance with relevant regulations and the Institutional Review Board (IRB) of icddr,b, Mohakhali, Dhaka, Bangladesh had approved the research protocol (protocol number: 2008-020). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Statement Data are available upon reasonable request. At icddr,b, we adhere to a strict policy to ensure that data containing identifying patient information is not made available. However, data related to this paper are available on request. Researchers who meet the criteria for accessing confidential data may request it by contacting Ms. Shiblee Sayeed (shiblee_s{at}icddrb.org) from the Research Administration of icddr,b (http://www.icddrb.org/).