Just one cigarette a day is enough to significantly increase the risk of heart disease and stroke, according to a new study.
The British Medical Journal report indicates that there is nothing safe about smoking, even at extremely low levels.
It found that just one cigarette a day increases the risk of heart disease by half and the risk of stroke by just under a third when compared to non-smokers.
Globally, around 48 per cent of smoking-related deaths are attributed to cardiovascular disease.
Allan Hackshaw, co-author of the research from University College London, said: “There seems to be a belief that cutting down a lot greatly reduces your chance of getting all smoking-related disorders.
“Whilst that is true for cancer, it doesn’t seem to be true for heart disease or stroke.”
The study looked at people who smoked on average one cigarette a day, five a day, or 20 a day, and those who didn’t smoke at all.
It found that when comparing one-a-day smokers to 20-a-day smokers, the risk of disease was not reduced as much as first thought. In fact, it was only around half that.
“The problem is with cardiovascular disease, the effects on the blood system, the heart, occur really quickly,” added Hackshaw.
“You only need a little bit of exposure to give you the big harmful effects; that is why the one cigarette per day carries a much bigger risk than many people realise. When you smoke up to 20 [a day] it gives you more risk, but not hugely more.”
Deborah Arnott, chief executive of the charity Action on Smoking & Health, urged smokers to cut the habit out “completely”.
“Sadly, many smokers are in denial and refuse to believe a few fags a day will do any harm,” she said.
“Vaping is much less harmful and smokers who can’t quit because they crave the nicotine should consider switching, but they need to stop smoking completely.”