Predictors of plasma lead among lithographic print shop workers in Mexico City

BACKGROUND: Plasma lead is considered a biological marker that reflects the fraction of lead in blood that is toxicologically available. We examined the relationship between plasma lead and other biomarkers of lead exposure in 69 lithographic print shop workers. METHODS: Lead was measured in plasma and whole blood (by inductively coupled plasma-magnetic sector mass spectrometry), in bone (by 109Cd X-ray fluorescence), and in hand wipes and occupational air samples. Personal hygiene habits at work were surveyed. RESULTS: Mean age was 47 years and 86% (n=59) were men. Mean lead levels were 0.3 microg/L in plasma, 11.9 microg/dL in blood, 46.7 microg/g in patella, and 27.6 microg/g in tibia. Taken together, two multivariate linear models explained 57% of variability in plasma lead levels. Predictors for the first model were lead in patella (beta = 0.006), blood (beta = 0.008), and hygiene index (beta = -0.11). Predictors for the second model were lead in tibia (beta = 0.008), blood (beta = 0.008), and hygiene index (beta = -0.13). CONCLUSIONS: This study demonstrates that accumulated bone stores and hygiene habits are both significant independent predictors of plasma lead levels in active workers at this print shop.