Effects of smoking on trace metal levels in saliva

Abstract

The aim of this study was to compare the salivary levels of trace metals between nonsmokers and smokers using inductively coupled plasma mass spectroscopy (ICP-MS). The effect of pre-treatment methods on the accuracy of ICP-MS analysis and daily variations in trace metal levels in saliva were also investigated. The participants were 10 male non-smokers (mean age: 27.4 ± 3.4 years) and 30 male smokers (mean age: 26.5 ± 4.1 years). Unstimulated whole saliva was collected. Salivary flow rate, the number of metal restorations in the oral cavity, the level of blood contamination in the saliva, and the levels of cotinine and trace metals in the saliva of each participant were determined. The obtained results were as follows: 1. Direct dilution of saliva samples with nitric acid showed the most accurate ICP-MS results among the tested pre-treatments. 2. Trace metal levels in saliva showed wide daily variations. 3. Trace metal levels in saliva were not affected by the number of metal restorations in the oral cavity. 4. The concentrations of magnesium, aluminum, and copper in saliva had significant negative correlations with salivary flow rate. 5. The salivary concentrations and salivary secretion rates of cotinine and aluminum were significantly increased in smokers compared with non-smokers. In conclusion, saliva can be a medium for trace metal analysis. Smoking status has significant effects on cotinine and aluminum levels in human saliva.