Figure 1.

Metabolic profiling in molecular epidemiology: a methodology to identify intermediate biomarkers of response to environmental toxicants. A) Map of United Kingdom showing Bristol region. Reproduced from Ordnance Survey map data by permission of the Ordnance Survey ^© Crown copyright 2010. B) Air Cd concentration around the Avonmouth zinc smelter site (data from Thomas et al. (2009)[37]). Contours represent modeled air Cd concentration (ng/m³). Dotted line represents boundary of Bristol North PCT from where volunteers were recruited. C) Partial ¹H NMR one dimensional spectrum with key metabolites annotated. 3-HV, 3-hydroxyisovalerate; DMG, dimethylglycine. D) Outline of the metabolic profiling and statistical methods used to define associations between the metabolome and environmental toxicants.