Researchers have found an increased incidence of end-stage renal disease (ESRD) in adults with high blood lead levels as a result of occupational exposure, especially among nonwhites, according to an online report in the American Journal of Kidney Diseases.

The finding, which came from a study of 58,307 men in an occupational surveillance system in 11 states, suggest that current occupational limits on blood lead levels may need to be strengthened, Ritam Chowdhury, PhD, and colleagues at Emory University in Atlanta concluded.

The median follow-up for the men was 12 years. The investigators mainly found excess risk for ESRD only among men in the highest blood lead level category (above 51 μg/dL). In these subjects, the incidence of ESRD was 1.47 times greater than would be expected in the general U.S. population, with the incidence higher for nonwhites than whites (2.12 times greater vs. 1.14 times greater). “Our finding may imply that high lead exposure exacerbates the already high underlying risk for the nonwhite group,” Dr. Chowdhury’s group observed.

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At a blood level threshold of 50 μg/dL, the Occupational Safety and Health Administration (OSHA) requires removal of construction workers to a lower exposed job until their blood lead level falls to below 40 μg/dL, the authors pointed out. For other workers, these limits are 60 μg/dL or higher on a single test or a series of recent tests averaging greater than 50 μg/dL.

“Given that repeated intermittent high exposures can lead to a high body burden over time, which may lead to kidney damage, the precautionary principle would suggest that the present OSHA standard, even if consistently enforced, may not be sufficiently protective,” the authors wrote.

The men in the study were participants in the Adult Blood Lead Epidemiology and Surveillance (ABLES) program sponsored by National Institute for Occupational Safety and Health.