Water pipe smoking is as bad as deeply inhaling cigarette smoke when it comes to causing respiratory problems, according to a study published today.
Researchers led by Mohammad Hossein Boskabady at Masshad University of Medical Sciences in Iran monitored lung functions among 57 local water-pipe smokers, 30 deep-inhalation cigarette smokers and 51 normal-inhalation smokers.
They also studied 44 non-smokers for a comparison.
Wheezing occurred among 23 per cent of the water-pipe users, 30 per cent of the deep-inhalation and 21.6 per cent of normal-inhalation cigarette smokers, but only among 9.1 per cent of non-smokers.
Coughing occurred among 21 per cent, 36.7 per cent and 19.6 per cent of the smoking groups, compared with 6.8 per cent of non-smokers, according to the study, which measured smokers over three months in two consecutive years.
Sputum production, meanwhile, was found in 14 per cent, 10 per cent, 3.9 per cent respectively among the various smoking groups, but among 6.8 per cent of the non-smoking group.
The results, published in the peer-reviewed journal Respirology, adds a further scientific blow to the defenders of shisha who claim that water pipes are safer because they filter out tobacco toxins.
"Our findings reveal that there were profound effects of water-pipe smoking on lung function values, which were similar to the effects observed in deep-inhalation cigarette smokers," Mr Boskabady said.
"Normal" inhalation cigarette smoking, which relates to the amount of smoke inhaled per puff, had less of an effect compared to the water pipe, but still contributed significantly to respiratory disorders, the paper stressed.
According to a 2005 study by the UN World Health Organisation (WHO), water pipe smoke has high concentrations of toxic compounds, including carbon monoxide, heavy metals, cancer-causing chemicals and potentially addictive levels of nicotine.
Cigarette smokers typically take eight to 12 puffs over five to seven minutes, inhaling a total of 0.5 to 0.6 of a litre of smoke.
In contrast, water pipe sessions typically last 20-80 minutes, during which the smoker may take 50-200 puffs. The total smoke intake can range from 0.15 to one litre.
"The water pipe smoker may therefore inhale as much smoke during one session as a cigarette smoker would inhale consuming 100 or more cigarettes," the WHO said.
The Iranian research used a gadget called a spirometer to measure how deeply smokers inhaled and retained the puff.
"Normal" inhalers typically inhaled less than 10 per cent above a benchmark of lung inflation called tidal volume. For "deep" inhalers, it was typically more than 30 per cent, and for water-pipe smokers it was usually 40 per cent above tidal volume.