RESEARCH ARTICLE Blood nickel and chromium levels in association with smoking and occupational exposure among head and neck cancer patients in Tunisia Rim Khlifi & Pablo Olmedo & Fernando Gil & Molka Feki-Tounsi & Amine Chakroun & Ahmed Rebai & Amel Hamza-Chaffai Received: 8 October 2012 / Accepted: 3 January 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Chronic exposure to chromium (Cr) and nickel (Ni) has long been recognized as being capable to increase head and neck cancer (HNC) incidence among exposed human populations. This study represents the first biomoni- toring of Cr and Ni exposure in Tunisia and focuses on a possible association with HNC risk. The aim of the present study was to evaluate the concentrations of Cr and Ni in the blood of HNC patients and controls. Metals blood levels of 169 HNC patients and 351 controls were determined using a Perkin-Elmer Analyst 800 Atomic Absorption Spectrome- ter. Mean blood levels of Cr and Ni in HNC cases (52.15 and 111.60 μg/L, respectively) were significantly higher than those of controls (37.04 and 30.50 μg/L, respectively). Cases’ blood levels of Cr and Ni were significantly higher than those of controls after controlling for the other risk factors of HNC, including smoking, shisha consumption, occupational exposure, and nearby environment (P <0.05). Among these risk factors, smoking and occupational expo- sure presented the most significant association with HNC (odds ratio (OR)=6.54 and 7.66, respectively, P <0.001). Cr and Ni levels in blood sample of cases and controls that are smoker/occupationally exposed were higher than that of non- smoker/non-occupationally exposed (P <0.05). Smokers who are occupationally exposed present the most significant asso- ciation with HNC (OR=25.08, P <0.0001). High levels of blood Cr (OR=2.09) and high levels of blood Ni (OR=8.87) were strongly associated with HNC after other potential con- founders were controlled (P=0.004 and P <0.0001, respec- tively). This study suggested a potential role of Cr and Ni in the mechanism of HNC development. Keywords Chromium . Nickel . Head and neck cancer . Tobacco smoking . Occupational exposure Introduction Head and neck cancers (HNC) are one of the sixth most common cancers worldwide (Stewart and Kleihues 2003a; Khandekar et al. 2006). The highest incidences of HNC have been found in South Asia, some parts of central and southern Europe (Blot et al. 1988), and Northern Africa, and two thirds of these cases are occurring in developing countries (Ferlay et al. 2004). Each year, there are approx- imately 560,000 new cases and 300,000 deaths due to HNC (Boyle and Levine 2008), and 90 % of HNC are squamous cells carcinomas (Curado and Hashibe 2009). The incidence of HNC was 18.3/100,000/year (Ben Abdallah et al. 2003) in north and 20.6/100,000/year in south of Tunisia (Sellami et al. 2007). Tobacco exposure and alcohol drinking have been estab- lished as major risk factors of HNC in most of countries in the world (Stewart and Kleihues 2003b; Boyle and Levine 2008). Tobacco carcinogenicity is more than evident, and about one fourth of oral cancer cases are attributable to cigarette smoking (Hashibe et al. 2007). Specifically, Responsible editor: Philippe Garrigues R. Khlifi : M. Feki-Tounsi : A. Hamza-Chaffai Unit of Marine and Environmental Toxicology, UR 09-03, Sfax University, IPEIS, BP 1172, 3018, Sfax, Tunisia R. Khlifi (*) : M. Feki-Tounsi : A. Rebai Bioinformatics Unit, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia e-mail: rimkhlifi@yahoo.fr P. Olmedo : F. Gil Department of Legal Medicine and Toxicology, University of Granada, Granada, Spain A. Chakroun Department of Otorhinolaryngology, Habib Borguiba Hospital, Sfax, Tunisia Environ Sci Pollut Res DOI 10.1007/s11356-013-1466-7