 despite the recent declines in environmental lead exposure in the united states and mexico , the potential for delayed toxicity from bone lead stores remains a significant public health concern . 
 some evidence indicates that mobilization of lead from bone may be markedly enhanced during the increased bone turnover of pregnancy and lactation , resulting in lead exposure to the fetus and the breast - fed infant . 
 we conducted a cross - sectional investigation of the interrelationships between environmental , dietary , and lifestyle histories , blood lead levels , and bone lead levels among 98 recently postpartum women living in mexico city . 
 lead levels in the patella ( representing trabecular bone ) and tibia ( representing cortical bone ) were measured by k x - ray fluorescence ( kxrf ) . 
 multivariate linear regression models showed that significant predictors of higher blood lead included a history of preparing or storing food in lead - glazed ceramic ware , lower milk consumption , and higher levels of lead in patella bone . 
 a 34 micrograms / g increase in patella lead ( from the medians of the lowest to the highest quartiles ) was associated with an increase in blood lead of 2.4 micrograms / dl . given the measurement error associated with kxrf and the extrapolation of lead burden from a single bone site , this contribution probably represents an underestimate of the influence of trabecular bone on blood lead . 
 significant predictors of bone lead in multivariate models included years living in mexico city , lower consumption of high calcium content foods , and nonuse of calcium supplements for the patella and years living in mexico city , older age , and lower calcium intake for tibia bone . 
 low consumption of milk and cheese , as compared to the highest consumption category ( every day ) , was associated with an increase in tibia bone lead of 9.7 micrograms pb / g bone mineral . 
 the findings of this cross - sectional study suggest that patella bone is a significant contributor to blood lead during lactation and that consumption of high calcium content foods may protect against the accumulation of lead in bone.imagesfigure 1.figure 1.figure 2.figure 2 . 
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