Background: Epidemiologic studies of occupational lead exposure have suggested increased risks
of cancers of the stomach, lung, kidney, brain, and meninges; however, the totality of the evidence
is inconsistent.
Objective: We investigated the relationship between occupational lead exposure and cancer
incidence at the five abovementioned sites in two prospective cohorts in Shanghai, China.
Methods: Annual job/industry-specific estimates of lead fume and lead dust exposure, derived
from a statistical model combining expert lead intensity ratings with inspection measurements,
were applied to the lifetime work histories of participants from the Shanghai Women’s Health
Study (SWHS; n = 73,363) and the Shanghai Men’s Health Study (SMHS; n = 61,379) to estimate
cumulative exposure to lead fume and lead dust. These metrics were then combined into an overall
occupational lead exposure variable. Cohort-specific relative hazard rate ratios (RRs) and 95%
confidence intervals (CIs) comparing exposed and unexposed participants were estimated using Cox
proportional hazards regression and combined by meta-analysis.
Results: The proportions of SWHS and SMHS participants with estimated occupational lead
exposure were 8.9% and 6.9%, respectively. Lead exposure was positively associated with meningioma
risk in women only (n = 38 unexposed and 9 exposed cases; RR = 2.4; 95% CI: 1.1, 5.0),
particularly with above-median cumulative exposure (RR = 3.1; 95% CI: 1.3, 7.4). However, all
12 meningioma cases among men were classified as unexposed to lead. We also observed nonsignificant
associations with lead exposure for cancers of the kidney (n = 157 unexposed and 17 ever
exposed cases; RR = 1.4; 95% CI: 0.9, 2.3) and brain (n = 67 unexposed and 10 ever exposed cases;
RR = 1.8; 95% CI: 0.7, 4.8) overall.
Conclusions: Our findings, though limited by small numbers of cases, suggest that lead is associated
with the risk of several cancers in women and men