PET dogs are forced to inhale the equivalent of up to 15 cigarettes a day by owners with a regular nicotine habit, Scottish scientists have discovered.
Research at the University of Glasgow found high levels of nicotine in the hair of pets living in households with smokers .
The team say exposure to cigarette smoke is almost certain to result in an increased chance pet dogs will suffer cancer or other serious conditions.
Around one in four dogs is struck down by cancer and vets say it does not even occur to many smokers they are putting their pets at risk.
The Glasgow researchers closely examined the coats of 38 dogs – 23 of which had been had been exposed to “environmental tobacco smoke”.
Sixteen pets had been exposed to tobacco smoke regularly, through close contact with smoking owners, in their home, during car travel, or outdoors.
The amount of nicotine in these dogs’ coats – a reliable indicator of their exposure to cigarette smoke – ranged from 1mg to 11.3mg.
The higher figure is the equivalent of directly smoking up to 15 cigarettes a day, according to Professor Claire Knottenbelt, who led the study.
She said the research proved without a doubt that carcinogens would have passed into the dogs – and statistically almost certainly increase their risk of cancer.
The Professor of Small Animal Medicine and Oncology at Glasgow University said: “An average dog, regularly exposed, smokes between one cigarette per day and one cigarette per week depending on coat variables
“A dog with 11mg smoked about 11-15 cigarettes per day.”
She added: “In non-smoking environments, the amount of nicotine to hair concentration was generally low, or zero.
“With dogs that had been exposed to cigarette smoke, it was very high and comparable to children in a passive-smoking environment.
“There has been a very big drive to link a children’s exposure to smoke in the house, but with dogs, people don’t think about it.
“They love their pets – in some cases more than they love their children – but they don’t stop and think.”
The professor, who regularly treats dogs with cancer, said: “People will often bring their pets in, smelling of smoke, and they are still not making the link with smoking.
“We don’t want people to feel guilty but it’s my hope that people seeing there pet when it’s unwell that they will hopefully look at their own smoking habits and it may encourage them to stop.”
There are at least half a million dogs in Scotland, and one in four will suffer from cancer.
Symptoms of lung cancer – which has a 50% survival rate in canines – include lethargy, weight loss, a chronic cough, lameness and difficulty breathing.
It is amongst the most expensive cancer treatment for dogs, and can cost owners up to £4,000 to treat.
Many vets are likely to suggest putting down dogs in these circumstances because of the enormous cost of treatment.
The Glasgow study, carried out in conjunction with the British Small Animal Veterinary Association’s Petsavers Charity, and animal charity PDSA, is just the first step.
Prof Knottenbelt is planning research which aims precisely to measure the amount and type of carcinogens inhaled by the pet dogs of smokers.
Researchers will attach a backpack device to the pets, provided by volunteer owners, which will monitor chemicals in the immediate environment.
She added: “I think the results of the preliminary study probably underestimates how affected dogs are by passive smoking.
“The backpack study will look at what is in the air around the dog. Nicotine is a marker, this will tell us how many nasty carcinogens the dogs are being exposed to.”
Libby Anderson, of animal charity OneKind, said: “OneKind welcomes the research by Glasgow as a significant step towards protecting animals and people from suffering a preventable disease.
“It also underlines the close and complex relationship between families and their pets – and if people give up smoking because they care about their pets, that’s a very good thing.”