We did not consider differential risk prediction in different subpopulations. Emerging evidence suggests that certain subgroups may be more responsive to environmental pollutant exposure. Women are known to take up more divalent metals such as lead and cadmium due to iron depletion [71]. Stronger associations between lead and hypertension have been found in some racial/ethnic populations [72], [73]. Sex- or race/ethnic group-specific biological differences, such as differences in body iron and estrogen levels between men and women, or socially determined gender- or race/ethnic group differences, such as different psychosocial stress levels, may confer susceptibility to health responses to pollutant exposures [74], [75]. Sex-specific or race/ethnic group-specific ERS’s may provide better risk prediction as well as risk assessment.
