Waterpipe Tobacco Chemical Content, Microbial Contamination, and Genotoxic Effects: A Systematic Review.

The spread of tobacco smoking has increased over time at the global and national levels. One of the widely spread tobacco products is waterpipe. Recent studies showed that waterpipe tobacco smoke contains toxic substances, including carbon monoxide and nicotine. Some of them are genotoxic carcinogen, such as formaldehyde. This study aims to provide comprehensive insight into the types and depth of the scientific literature on waterpipe tobacco smoke chemical content, its genotoxic effects, and waterpipe device microbial contamination. We conducted a systematic comprehensive review of articles published between 1986 and December 2018. Primary research articles focusing on the content of waterpipe smoke, including chemical, genotoxic, and microbial contaminants, were eligible for inclusion. Of the 1,286 studies generated, 22 studies were included. Twenty-three chemical families were extracted from waterpipe smoke. Aldehydes were the most identified chemical family in 6 studies, and next is polycyclic hydrocarbons, found in 5 studies. About 206 chemical compounds were identified. Flavobacterium, Pseudomonas, coagulase-negative Staphylococci, and Streptococcus were the most abundant pathogen contaminants. Waterpipe smoke had elevated levels of many DNA damage markers (8-hydroxy-2'-deoxyguanosine and cytochrome P450 1A1) and inhibited levels of many DNA repair genes (OGG1 and XRCC1) in waterpipe smokers. Waterpipe smoke is associated with the genotoxic effect, which elevates the levels of many DNA damage markers and inhibits the levels of many DNA repair genes. In addition, waterpipe smoking can expose smokers to a range of pathogenic bacteria.