Factors related to children and their family In the multivariate regression model, two factors related to lead contamination in children was male sex (aOR = 2.66, 95% CI: 1.22 - 5.77, p = 0.013) in Ban Thi, Bac Kan and distance from house to mining area less than 2 km (aOR = 2.23; 95% IC: 1.19 - 4.2; p = 0.012) in Tan Long, Thai Nguyen.