Sydney: Men who smoke a pack or more of cigarettes daily are 40 per cent more likely to be impotent than non-smokers, finds research in Tobacco Control.

The research team analysed the questionnaire responses of over 8000 men aged between 16 and 59 who were taking part in the Australian Study of Health and Relationships.

Almost one in 10 of the men said that they had had erectile problems lasting a month or more during the preceding year.

More than a quarter of the respondents were smokers, one in five of whom smoked 20 or fewer cigarettes a day. Just over 6% smoked 20 or more a day.

The results pointed to a significant association between smoking and erectile problems, which became stronger with increasing numbers of cigarettes smoked.

When compared with non-smokers, those who smoked 20 or fewer cigarettes a day were 24 per cent more likely to report difficulties maintaining an erection. Those smoking more than a pack a day were 39 per cent more likely to report erectile difficulties.

Unsurprisingly, older age and a diagnosis of cardiovascular disease were also associated with a greater likelihood of erectile problems. But moderate drinking significantly cut the risk.