Blood pressure and industrial lead exposure

The association between environmental lead exposure and raised blood pressure remains controversial. This association was examined in a cross-sectional study in 1981 on 809 male workers who were occupationally exposed to lead in a factory manufacturing car lead accumulator batteries in Birmingham, United Kingdom. Lead exposure was assessed by blood lead levels, blood zinc protoporphyrin levels, and years of industrial exposure to lead. The geometric mean blood lead level was 31.6 micrograms/dl with minimum and maximum values of 0 microgram/dl and 98 micrograms/dl, respectively. Unadjusted systolic blood pressure rose with increasing blood lead levels (analysis of variance, F = 3.3, p < 0.05) from 127 mmHg (95% confidence interval (CI) 123.5-130.5) in men with blood lead levels less than 21 micrograms/dl to 133 mmHg (95% CI 128.7-137.3) in men with levels exceeding 50 micrograms/dl. Following adjustment for the confounding effects of age, body mass index, and alcohol consumption, however, the effect of blood lead on systolic pressure was diminished (analysis of variance, F = 1.3, not significant) to 129 mmHg and 132 mmHg in the respective categories. There was no association between diastolic blood pressure and blood lead. Zinc protoporphyrin levels and years of industrial lead exposure did not raise adjusted systolic or diastolic pressure. In conclusion, subject to the limitations inherent in a cross-sectional survey, the findings are consistent with a weak effect of industrial lead exposure on systolic blood pressure, within the range of exposures observed in this study.