Fig. 3
Association between lead content per unit calcium and age at death of study population. Quadratic regression analysis was carried out to generate best-fit lines as they result in higher R2 values than linear regression in the three series of data. The cluster A (younger and high in bioaccumulation) (red line) shows a relationship of inverse U appearance between age and calcium adjusted lead levels as they had a shorter life span with higher lead accumulation. Cluster B showed a low level of bioaccumulation (orange line) as compared to cluster A but with a higher level of bioaccumulation than the controls (green line)