Variation in cancer incidence in northeastern Belgium and southeastern Netherlands seems unrelated to cadmium emission of zinc smelters

Abstract

Exposure to cadmium has been established to be carcinogenic for humans by the International Agency for Research on Cancer, but this is mainly based on studies with occupational exposures. The substantial 100 year long emission of cadmium by three zinc smelters in the Kempen area across the Dutch-Belgian border might have affected the incidence of cancer in this region. Following a study of increased risks of lung cancer due to cadmium emission (hazard ratio was 4.2 for high vs. low cadmium exposure areas in that study), we used data from the three regional population-based cancer registries, covering an area with 2.9 million inhabitants. Analyses of observed incidence were carried out for all cancers and cancer of the lung, kidney, bladder, prostate, testis, and breast separately. At the municipality level standardized incidence ratios were calculated and smoothed using a Poisson-gamma or a conditional autoregressive model. To detect clusters and to calculate an observed/expected ratio (O/E ratio) for each cluster a spatial scan statistic was applied. Significantly increased cancer incidence rates were found at a multimunicipality level for female lung cancer (O/E ratio=1.2), male and female bladder cancer (O/E ratio male=1.8, O/E ratio female=1.7), and prostate cancer (O/E ratio=1.3), none of these clusters being located specifically around the area of the zinc smelters. Therefore, the long term emission of cadmium by the zinc smelters in the Kempen area did not seem to lead to an increase in the incidence of all cancers, and lung, kidney, bladder, prostate, testicular, or breast cancer.

Testicular Cancer: Genes, Environment, Hormones

“…In 2011, an epidemiological study for cancer incidence was performed in the Kempen area across the Dutch-Belgian border, featuring the very long activity of cadmium and zinc smelters. Compared to the control population, identified through regional population-based cancer registries, environmental exposure to Cd showed an increased risk for female lung cancer, male and female bladder cancer and prostate cancer but not TC (106). Similarly, another study focused on the north-east Belgium area investigated the ~17 years incidence of cancers, finding an overall increased risk of doubling the 24-h urinary cadmium excretion, however no significant association with TC was documented (107).…”

Adolescent and adult risk factors for testicular cancer

“…An ecologic study in the Netherlands and Belgium of various malignancies (including testicular cancer) in municipalities either close to or distant from a cadmium smelter found no difference in their incidence. 109 Similarly, a case–control study from the Netherlands reported no testicular cancers among men with occupational exposure to cadmium. 110 …”

Cadmium from zinc smelter emission and variation in cancer incidence

“…The conclusion in the recent report of Verhoeven et al (2011) on the incidence of cancer in relation to cadmium (Cd) emission of zinc smelters in the Belgian Noorderkempen remains far from convincing and is at variance with our results (Nawrot et al, 2006). We showed that the risk of lung cancer significantly correlated with indicators of environmental Cd exposure (soil Cd, residence in a high-exposure area), and more importantly, that allcancer, lung cancer risk, and mortality were significantly dose-related with 24 h urinary excretion of Cd (Nawrot et al, 2006(Nawrot et al, , 2008, a good surrogate biomarker of internal Cd dose reflecting an individual's lifetime-integrated Cd exposure.…”