Comparative evaluation of salivary levels of malondialdehyde and lactate dehydrogenase in active and passive smokers

This study is conducted aiming to assess and compare the salivary levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) in active and passive smokers to determine the correlation between environmental tobacco smoke and health condition. This study evaluated 75 healthy individuals including 25 active smokers, 25 passive smokers, and 25 non-smokers with an equal percentage of males and females. Unstimulated saliva samples were collected from all participants. The salivary level of cotinine was first measured for correct allocation of participants to the aforementioned three groups using enzyme-linked immunosorbent assay (ELISA) technique. The salivary levels of MDA and LDH were then measured. The salivary level of cotinine was 19.1, 8.12, and 3.36 nmol/ml in active smokers, passive smokers, and non-smokers, respectively. The salivary level of MDA was 4.78, 2.67, and 2.63 nmol/ml while the salivary level of LDH was 508.33, 364.98, and 271.63 nmol/ml in active smokers, passive smokers, and non-smokers, in the order given. Acceding to the results, the salivary levels of cotinine, MDA, and LDH had significant correlations with cigarette smoking. The salivary levels of MDA and LDH were significantly higher in active smokers than passive smokers, and also the values in passive smokers were higher than the corresponding values in non-smokers (P < 0.05).