Water-pipe smoking is as bad as deeply inhaling cigarette smoke when it comes to causing respiratory problems, according to a study published on Thursday.
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 percent of the water-pipe users, 30 percent of the deep-inhalation and 21.6 percent of normal-inhalation cigarette smokers, but only among 9.1 percent of non-smokers.
Coughing occurred among 21 percent, 36.7 percent and 19.6 percent of the smoking groups, compared with 6.8 percent of non-smokers, according to the probe, which measured smokers over three months in two consecutive years.
Sputum production, meanwhile, was found in 14 percent, 10 percent, 3.9 per cent respectively among the various smoking groups, but among 6.8 percent 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.
The water pipe, often used with sweet or fruit-flavoured tobacco, is a centuries-old tradition in the Middle East but in recent years has become fashionable among young westerners, particularly women.
"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," Boskabady said in a press release.
"Normal" inhalation cigarette smoking 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, waterpipe sessions typically last 20-80 minutes, during which the smoker may take 50-20 puffs which each range from 0.15 to one litre each.
"The waterpipe 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 percent above a benchmark of lung inflation called tidal volume. For "deep" inhalers, it was typically more than 30 percent, and for water-pipe smokers it was usually 40 percent above tidal volume.