Stunting and lead: using causal mediation analysis to better understand how environmental lead exposure affects cognitiv
- PDF / 808,750 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 88 Downloads / 162 Views
(2020) 12:39
RESEARCH
Open Access
Stunting and lead: using causal mediation analysis to better understand how environmental lead exposure affects cognitive outcomes in children Kelsey M. Gleason1, Linda Valeri2, Anuraj H. Shankar3, John F. Obrycki4 , Md Omar Sharif Ibne Hasan5, Golam Mostofa5, Quazi Quamruzzaman5, Robert O. Wright6,7, David C. Christiani8, David C. Bellinger4,8 and Maitreyi Mazumdar4,8*
Abstract Background: Many children in Bangladesh experience poor nutritional status and environmental lead exposure, both of which are associated with lower scores on neurodevelopmental assessments. Recent studies have suggested that part of lead’s adverse effects on neurodevelopment are caused in part by lead’s effect on growth. New statistical methods are now available to evaluate potential causal pathways in observational studies. This study used a novel statistical method to test the hypothesis that stunting, a measure of linear growth related to poor nutrition, is a mediator and/or an effect modifier of the lead exposure’s adverse effect on cognitive development. Methods: Participants were 734 children from a longitudinal birth cohort established in rural Bangladesh to study the health effects of prenatal and early childhood environmental metal exposures. Lead exposure was estimated using umbilical cord blood samples obtained at birth and blood obtained via venipuncture at age 20–40 months. Stunting was determined using the World Health Organization’s standards. Neurodevelopment was assessed at age 20–40 months years using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). We evaluated the effect of lead on stunting and whether the effect of lead on cognitive scores is modified by stunting status in multivariable regression analyses. We then conducted a novel 4-way mediation analysis that allows for exposure-mediator interaction to assess how much of the effect of lead on cognitive scores is explained by the pathway through stunting (mediation) and how much is explained by the interaction between lead and stunt (effect modification). (Continued on next page)
* Correspondence: [email protected] 4 Department of Neurology, Boston Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115, USA 8 Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Comm
Data Loading...
