Lead effect on blood pressure in moderately lead-exposed male workers

Background The effect of lead (Ph) and potential confounding variables on blood pressure was examined in healthy male industrial workers 20 - 43 years of age. Methods In 100 Ph workers and 51 reference subjects, the following variables were measured: blood Pb (BPb), activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum zinc (SZn), serum copper (SCu), hematocrit (Hct), body mass index (BMI), and blood pressure. The interrelationship of biomarkers of Pb (BPb, ALAD, EP) and BCd, SZn, SCu, Hct, BMI, age, smoking, and alcohol to systolic and diastolic blood pressure was calculated by forward stepwise multiple regression. Results There was no significant difference in blood pressure between the two groups, possibly because the reference subjects had relatively high BPb levels and significantly higher BMI (P < 0.05) as compared to the Ph workers. According to the multiple regression results in Pb workers, an increase in systolic blood pressure was significantly associated with increasing EP (P = 0.001) and BMI (P < 0.002), or alternatively with increasing BMI (P < 0.004) and decreasing ALAD (P < 0.04) and BCd (P < 0.05). An increase in diastolic blood pressure was significantly associated with increasing BMI (P < 0.009) and EP (P = 0.05) and decreasing BCd (P < 0.04). With respect to the EP range of 0.73 - 13.94 mumol/l erythrocytes in 100 Pb workers, an increase of 17 mmHg in systolic and 6 mm Hg in diastolic blood pressure was found. Conclusions Long-term cumulative Pb exposure, which is better reflected by EP than by ALAD or current BPb level, can significantly increase blood pressure in moderately Pb-exposed male workers (long-term average BPb < 400 mug/l; exposure duration 2 - 21 years). Am. J. Ind. Med. 45:446-454, 2004. (C) 2004 Wiley-Liss, Inc.