Smoking is the main reason why on average men die sooner than women across Europe, according to research.
World Health Organization figures on death rates reveal tobacco-related illness accounts for up to 60% of the gender health gap in most countries.
In the UK, women live an average of four years longer than men, although in recent years the gap has been closing.
Second to smoking, alcohol accounts for about 20% of the disparity, the journal Tobacco Control reports.
Some experts have claimed the difference is down to simple biology or the fact that women seek medical help more readily than men.
But the latest findings suggest smoking is the main culprit.
Across 30 European countries, which included the UK, deaths from all causes were higher for men than for women.
Iceland and the UK ranked the lowest, with around 200 excess male deaths per 100,000 population each year, while Lithuania and Ukraine ranked the highest, at over 800 excess male deaths per 100,000.
When the researchers looked at what had contributed to the deaths, they found smoking was behind 40% to 60% of the gender gap in all countries, except Denmark, Portugal and France, where it was lower, and Malta where it was much higher - at over 70%.
In the UK, smoking-related diseases, such as lung cancer and heart disease, caused 60% of the excess male deaths.
Dr Gerry McCartney, who led the research for the UK's Medical Research Council, said: "This study shows it's not simply a biological difference between men and women.
"The fact that the gender gap varies between countries shows it is social causes, and largely smoking-related."
He said it was promising that smoking rates were going down as more people decided to kick the habit.
But he said there was a worrying trend of smoking and drinking now emerging among young women, which needed to be kept under close scrutiny.
Although smoking is behaviour often tied up with other social factors - such as deprivation - that can impact on health, it is something that is relatively simple to tackle, say experts.
Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said: "It is never too late to give up smoking so it's important we invest in support services to help people quit the habit as well as ensuring our young people don't start smoking in the first place.
"That's why we want to see the removal of displays of cigarettes from shops - a form of tobacco marketing which entices youngsters into a life addiction and health problems."