Lead accumulation in teeth as a function of age with different exposures.

The level of lead exposure in industrial, urban, and rural populations has been evaluated by sampling permanent teeth gathered from three regions of Belgium. When tooth lead concentrations are plotted against tooth age, a linear function appears to fit the empirical results satisfactorily. On the contrary, comparing only the arithmetical means of the three samples would bring a possible bias of the results because their mean ages are different. The slope of the three best regression lines obtained respectively with data from the three regions increases significantly in the sequence rural less than urban less than industrial. A simplified mathematical model shows that this slope is directly related to the mean intake of lead under uniform exposure. It is suggested that this slope could be used as an index of the population's exposure to lead.