Estimation of toxic elements in the samples of different cigarettes and their effect on the essential elemental status in the biological samples of Irish smoker rheumatoid arthritis consumers

Cigarette smoking interferes with the metal homeostasis of the human body, which plays a crucial role for maintaining the health. A significant flux of heavy metals, among other toxins, reaches the lungs through smoking. In the present study, the relationship between toxic element (TE) exposure via cigarette smoking and rheumatoid arthritis incidence in population living in Dublin, Ireland, is investigated. The trace {zinc (Zn), copper (Cu), manganese (Mn), and selenium (Se)} and toxic elements arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) were determined in biological (scalp hair and blood) samples of patients diagnosed with rheumatoid arthritis, who are smokers living in Dublin, Ireland. These results were compared with age- and sex-matched healthy, nonsmoker controls. The different brands of cigarette (filler tobacco, filter, and ash) consumed by the studied population were also analyzed for As, Cd, Hg, and Pb. The concentrations of trace and TEs in biological samples and different components of cigarette were measured by inductively coupled plasma mass spectrophotometer after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked using certified reference materials. The recovery of all the studied elements was found to be in the range of 96.4–99.8 % in certified reference materials. The filler tobacco of different branded cigarettes contains Hg, As, Cd, and Pb concentrations in the ranges of 9.55–12.4 ng, 0.432–0.727 μg, 1.70–2.12 μg, and 0.378–1.16 μg/cigarette, respectively. The results of this study showed that the mean values of As, Cd, Hg, and Pb were significantly higher in scalp hair and blood samples of rheumatoid arthritis patients as compare to healthy controls, while Zn, Cu, Mn, and Se concentrations were found to be lower in rheumatoid arthritis patients, the difference was significant in the case of smoker patients (p < 0.001). The levels of four toxic elements were 2–3-folds higher in scalp hair and blood samples of nonrheumatoid arthritis smoker subjects as compared to nonsmoker controls. The high exposure of toxic metals as a result of cigarette smoking may be synergistic with risk factors associated with rheumatoid arthritis.