Cancer incidence among Finnish male cobalt production workers in 1969–2013: a cohort study

Abstract

BackgroundThere is inadequate evidence for the carcinogenicity of cobalt and cobalt compounds in humans. Consequently, the International Agency for Research on Cancer (IARC) has evaluated cobalt metal without tungsten carbide as possibly carcinogenic to humans (Group 2B). The aim of the study was to assess the risk of cancer among workers employed in a Finnish cobalt plant since the beginning of production in 1968.MethodsThe study cohort consisted of all males employed by the Finnish cobalt plant for at least a year during 1968–2004. The follow-up for cancer was performed by studying the files of the Finnish Cancer Registry, using personal identity codes as a key. The cohort was divided into subcohorts by exposure levels. Standardised incidence ratios (SIRs) and 95% confidence intervals (95% CIs) were calculated as ratios of the observed numbers of cancer cases and the numbers expected on the basis of incidence rates in the population of the same region.ResultsThe follow-up cohort consisted of 995 men with 26,083 person-years. During the follow-up period, 92 cases of cancer were diagnosed (SIR 1.00, 95% CI 0.81–1.22), six of which were lung cancer cases (SIR 0.50; 95% CI 0.18–1.08). The only cancer type with increased incidence was tongue cancer (three cases, SIR 7.39; 95% CI 1.52–21.6). We observed no dose-response effect across the different exposure levels and the incidence of any cancer type.ConclusionsThe results suggest that occupational exposure to cobalt is not associated with an increased overall cancer risk or lung cancer risk among cobalt workers. Because of the small number of cancer cases the results must be interpreted with caution.

Mechanistic insight into reactivity and (geno)toxicity of well-characterized nanoparticles of cobalt metal and oxides

“…Furthermore, a study on transgenic mice clearly showed higher mutant frequency in lung tissue, as compared to controls (Wan et al 2017). In contrast, a recent cohort study on Finnish male cobalt production workers did not observe any increased cancer risk (Sauni et al 2017). These and other in vivo studies are highly valuable for assessing risks related to cobalt-based particles.…”

Association between heavy metals and colon cancer: an ecological study based on geographical information systems in North-Eastern Iran

“…However, excessive concentration of cobalt may damage human health [ 49 ]. Previous studies investigated the association between exposure levels of the cobalt and cancer incidence and reported controversial findings [ 50 – 52 ]. While some of these studies [ 50 , 51 ] reported that exposure level of the cobalt might increase the risk of cancer of the upper gastrointestinal tract and lungs, Sauni et al [ 52 ] suggest that occupational-exposure to cobalt may not be associated with an increased overall cancer risk.…”

Association Between Heavy Metals and Colon Cancer: An Ecological Study Based on Geographical Information Systems in Northeastern Iran

“…However, excessive concentration of cobalt may damage human health [33]. Previous studies investigated the association between exposure to cobalt and cancer incidence and reported controversial ndings [34][35][36]. A study by Turkdogan et.al [34] reported that heavy metals such as cobalt could be related to the high prevalence of upper gastrointestinal cancer rates, and another study [35] reported exposure to cobalt might increase the risk of lung cancer.…”

“…A study by Turkdogan et.al [34] reported that heavy metals such as cobalt could be related to the high prevalence of upper gastrointestinal cancer rates, and another study [35] reported exposure to cobalt might increase the risk of lung cancer. On the other hand, Sauni et al [36] suggested that occupational-exposure to cobalt may not be associated with increased overall cancer risk. Our study revealed that cobalt is signi cantly associated with colon cancer incidence in men.…”