A single smoking session from 'hookah', a large communal pipe used for shisha, delivers 25 times more tar than a cigarette, and 10 times more carbon monoxide. Research shows the water-based pipes supplies the user with 125 times more smoke than cigarettes, also delivering the huge amount of toxicants that come with it.

The researchers, from the University of Pittsburgh, found that one hookah session delivers 25 times the tar, 2.5 times the nicotine and 10 times the carbon monoxide than a single cigarette. This report comes following the news that for the first time, hookah tobacco was more widely used in US high schools than cigarettes.

"Our results show that hookah tobacco smoking poses real health concerns and that it should be monitored more closely than it is currently," said Brian Primack, lead author of the research. "For example, hookah smoking was not included in the 2015 Youth Risk Behaviour Surveillance Survey System questionnaire, which assesses cigarette smoking, chewing tobacco, electronic cigarettes and many other forms of substance abuse."

The study was published in Public Health Reports. It used 17 other pieces of research to come to their conclusion, which focused on the amount of tar, nicotine, carbon monoxide and smoke delivered from cigarettes and hookah.

The authors do say that this type of comparison is difficult, because users of cigarettes and hookah have different patterns of smoking. For example, the average amount of cigarettes smoked by cigarette users is between 16 and 20 per day. A typical hookah smoker would usually have no more than 3 sessions in one day.

"We had to conduct the analysis this way – comparing a single hookah session to a single cigarette – because that's the way the underlying studies tend to report findings," said Primack. "So, the estimates we found cannot tell us exactly what is 'worse.' But what they do suggest is that hookah smokers are exposed to a lot more toxicants than they probably realise."

The next stage of research is to obtain more specific data which takes into account user habits. After that, the researchers can compare the amount of toxicants received in the average hookah user, and the average cigarette smoker.

In the UK, roughly 10 million adults smoke cigarettes – just under one in six. On the other hand, nearly 14% of UK adults smoke from hookahs – just over one in seven.