Cross-sectional study protocol to assess the environmental exposure of endocrine disruptive chemicals: bisphenol-A and heavy metals in children

Introduction
Endocrine-disruptors are exogenous compounds that interfere with the human biological system. Bisphenol-A and toxic ele-mental mixtures (e.g. As, Pb, Hg, Cd, and U) are major endocrine-disruptive chemicals documented by the USEPA. Globally obesi-ty is a major health problem with increasing fast-food intake among children. The use of food packaging material is rising global-ly, becoming a primary source of chemical migration from food contact materials.

Material and methods
This protocol is a cross-sectional study, and the primary outcome is to assess the various dietary and non-dietary exposure sources of endocrine-disruptive chemicals (bisphenol A and heavy metals) through a questionnaire, and quantification of urinary bisphenol A and heavy metals using LC-MS/MS and ICP-MS, respectively, among children. In this study, anthropometric assess-ment, socio-demographic characteristics, and laboratory investigations will be performed. Exposure pathway assessment will be done using questions about household characteristics, surroundings, food and water sources, physical/dietary habits, and nutri-tional assessment.

Results
An exposure pathway model will be developed based on the questions on source, pathway/exposure, and receptor (child), of those exposed to or potentially exposed to the endocrine-disruptive chemicals.

Conclusions
The children who are exposed or potentially exposed to the chemical migration sources need intervention through local bodies, school curriculum, and training programs. Also, methodological points of view implication of regression models and the LASSO approach will be assessed to identify the emerging risk factors of childhood obesity and even reverse causality through multi-pathway exposure sources. The feasibility of the current study outcome can be implicated in developing countries.