Chronic renal disease among lead-exposed workers.

BACKGROUND

Very high exposure to inorganic lead causes serious kidney damage. We have studied workers with occupational exposure and data on blood lead.

METHODS

We extended follow-up for 7 more years, for a previously studied cohort of 58 307 male workers who were part of a surveillance programme in 11 different states. Mortality was assessed using the National Death Index, and end-stage renal disease (ESRD) incidence was assessed using the US Renal Data System. We conducted internal analyses via Cox regression adjusting for age, calendar time and race.

RESULTS

The cohort was followed for a median of 18 years and had 524 cases of ESRD and 6527 deaths. Average maximum blood lead was 26 µg/dL; the mean year of first blood lead test was 1997. No trends by lead level were seen overall or when restricting to those with 15+ years follow-up. Among non-Caucasians with >15 years of follow-up, there was a positive but inconsistent trend (Rate ratios (RRs) 1.00, 2.10, 1.33, 2.20 and 2.76 for maximum blood lead categories of <20 µg/dL, 20-29 µg/dL, 30 to <40 µg/dL, 40 to ≤50 µg/dL and >50 µg/dL, respectively (p for linear trend 0.26). Those with >15 years of follow-up and birth year <1941 showed a positive trend with increased blood lead (RRs 1.00, 1.14, 1.18, 1.46, 1.66, p trend=0.26).

CONCLUSIONS

We found no association between higher lead exposure and ESRD. There were positive but not statistically significant trends of increased risk for non-Caucasians with >15 years of follow-up and for older men with >15 years of follow-up.