Life expectancy in Sweden has risen steadily during the last few decades for most groups. One exception is women whose highest educational level is compulsory school. This is mostly because of smoking, says a new dissertation in sociology.

"Life expectancy has stayed level in the last 20-30 years for women with only a compulsory schooling in Sweden, but it's increased for other social groups. A big piece of this puzzle is ," say Olof Östergren, sociology researcher at Stockholm University.

The study is based on data from the registries of causes of death and for all Swedes who were 30-74 years old between 1991 and 2008. The research shows that inequality in longevity between different groups have increased among women during this period.

The statistics show that anticipated among women with only a primary education increased a little over a month between 1991 and 2008, while the comparable number for university educated women were five months. Not counting deaths attributable to smoking, the former group's life expectancy increased to four months and the latter's to just over five months.

"The differences may seem small, but when it's about anticipated life expectancy these numbers are dramatic. Deaths from smoking are three times more common among women with a compulsory education versus university educated ones," says Olof Östergren.

"Despite ambitious welfare policies, the social health disparities are not smaller in Sweden than in other countries, and these disparities are increasing more rapidly in Sweden than internationally. Alcohol consumption and smoking have been highlighted as contributing factors to these issues. My research backs up this picture," says Olof Östergren. "Deaths from smoking in Sweden has decreased among men and increased among women, particularly those with compulsory schooling. One possible explanation as to why men are less harmed by tobacco is snus. Snus isn't as dangerous as smoking, and it's much more common among men than ."

"Earlier research has shown that people in stressful life situations have a harder time stopping health endangering habits like smoking. This is partly because fewer of them try to quit and partly because people with fewer economic and social resources have a smaller chance of breaking the habit," says Olof Östergren.

A stressful life situation can also make the body more susceptible to the damaging effects of tobacco and alcohol. This means that differences in mortality depend both on behavioural differences and social and economic differences. On the other side, education provides access to a better work environment, higher status in the job market, more control over the work situation and higher income. The dissertation also shows that education is particularly important for health of those with low incomes.

"The theory behind this is that the fewer economic resources a person has, the more important the way that they spend the resources becomes. Education promotes effectiveness and the proper handling of resources, and that means that highly education groups can use all of their means to improve health. That's why education is particularly important for those with low incomes. Education is always good for health," says Olof Östergren.