A study in New Zealand showed that, three years after a smoking ban on all workplaces was introduced, hospital admissions for heart attacks among men and women aged 55-74 fell by 9 per cent. This figure rose to 13 per cent for 55-74 year olds who had never smoked.

Overall, the research showed heart attacks among people aged 30 and over fell by an average of 5 per cent in the three years following the ban.

The study, involving scientists from the University of Edinburgh, examined trends in acute heart attacks following a change in legislation. The ruling, which updates a previous law in which smoking was outlawed in some public places, makes smoking illegal in all workplaces including bars and restaurants.

Researchers also found that heart attacks were reduced for ex-smokers of all ages, and that there was a greater decrease in hospital admissions for men compared with women.

In addition, the study found that people in more affluent neighbourhoods benefited more from the ban than those in poorer areas. This may be because they visit cafes and restaurants more often or because they are more likely to use the smoking ban as an incentive to quit.

This short-term research indicates a link between a smoking ban in bars and restaurants and a reduction in severe heart attacks. However, more work is needed to look at the effects of the ban in greater detail, said Dr Jamie Pearce, of the University of Edinburgh's School of GeoSciences, who took part in the study.

The study, carried out with the Universities of Otago and Canterbury in New Zealand and the University of Southampton, was published in the Australian and New Zealand Journal of Public Health.