Project Summary (1995-2000)

This project is studying the effect of maternal lead bone stores, accumulated from environmental exposures, on lead exposure to fetuses and infants during pregnancy and lactation. K-x-ray fluorescence (K-XRF) is being used to measure bone lead levels in vivo in a new longitudinal study of lead exposure and reproduction among married women and men in Mexico. Mexican women of reproductive age have bone lead levels three times as high as women of comparable age in Boston. Mexican couples who are planning to conceive within one year right after they marry and register at the central Marriage Registry Bureau are being recruited in the first project phase. A thorough baseline evaluation of both men and women is being conducted including medical, environmental, occupational, dietary, and reproductive histories; semen collection; blood lead analysis; and K-XRF measured bone lead analysis. Another regimen is being conducted at three month intervals on couples selected for follow-up (based on the bone lead levels of the women) that includes in-depth home assessments. A second project phase begins if a woman becomes pregnant, at which time a testing regimen is repeated at each trimester and during lactation, with a K-XRF bone lead added during the post-partum period. The relative contributions of bone lead vs. environmental lead exposure to blood lead, change in blood lead during pregnancy and lactation, and bone lead as a predictor of adverse pregnancy outcomes is being determined from the data obtained. In addition, researchers are examining the proposed modifying influence of dietary calcium and polymorphism of the ALAD gene on these relationships, and the association between bone lead, blood lead, and sperm abnormalities among men.