In the new research, led by Oxford University and published in respiratory journal Thorax on Monday, researchers looked at genetic information and other data including smoking status, Covid tests, hospital admissions and death certificates.
Smokers are more likely to end up in hospital or die from Covid-19, according to new research.
Scientists said there has been conflicting evidence on the impact the disease has on those who use tobacco and cigarettes.
A study published in July 2020 claimed smokers were significantly less likely to be diagnosed with Covid compared to non-smokers.
But the paper was retracted earlier this year after it emerged its authors had links to the tobacco industry.
Of the 421,469 eligible participants in the study – the first of its kind in the UK – there were 1,649 confirmed infections, 968 Covid-related hospitalisations and 444 deaths.
The results of the analysis showed that, compared with never-smokers, current smokers had an 80 per cent higher risk of hospital admission with Covid.
The research also revealed that a genetic predisposition to smoking was associated with a 45 per cent higher risk of infection and a 60 per cent higher risk of hospital admission for Covid.
The authors concluded that their “results from two analytical approaches support a causal effect of smoking on risk of severe Covid-19”.
Dr Ashley Clift, the lead researcher from Oxford, said: “Our results strongly suggest that smoking is related to your risk of getting severe Covid, and just as smoking affects your risk of heart disease, different cancers, and all those other conditions we know smoking is linked to, it appears that it’s the same for Covid.
“So now might be as good a time as any to quit cigarettes and quit smoking.”
