For the world’s women, lung cancer is the second leading cause of cancer deaths, accounting for the deaths of nearly half a million women in 2012. The lung cancer mortality rate among women is increasing in many countries, according to a study by American Cancer Society researchers, published May 16 in the journal Cancer Epidemiology, Biomarkers, & Prevention.

This increase is not happening among all women, though. The authors found that it is due mainly to continuing increases among older women. Specifically, lung cancer death rates among women aged 50-74 are on the upswing in more than half of the countries analyzed.

Using data from the World Health Organization’s Cancer Mortality Database, the researchers analyzed lung cancer death rates among women across 65 countries from 2006 to 2010.

The picture is better for younger women (those aged 30-49). Their lung cancer death rates are stable or declining in almost all of the countries included in the study.

The authors attribute this age divergence – as well as differences found across countries – to variations in smoking patterns. Lung cancer death rates among older women are increasing in places where the uptake of smoking began later in the 20th century, including parts of Eastern, Southern, and Western Europe and in South America.

In these same regions, though, death rates for younger women tend to be steady or heading downward. The study authors say these declines are likely due to tobacco control measures and a growing awareness of the dangers of smoking. Both of those factors lead to fewer young women starting to smoke, and help increase the number of women quitting.

“Evidence of changes in cancer risk factor behaviors, like reductions in the number of people taking up smoking, are usually first reflected in the cancer rates of young adults,” says Rebecca Siegel, MPH, a co-author on the study and director of surveillance information at the American Cancer Society.

In order to expedite declines in deaths from lung cancer among older women, the authors suggest countries should implement “intensive smoking cessation efforts aimed at older women.”

“Successful tobacco control measures include increasing the cost of cigarettes, lowering social acceptability with public smoking bans and restrictions on advertising, and importantly, getting the word out that tobacco is the single most preventable cause of death worldwide,” says Siegel.

Raising taxes on tobacco is a major goal of the World Health Organization. The organization aims to bring additional attention to this issue by marking World No Tobacco Day every year on May 31.

“Raising taxes is one of the most effective ways to keep people from smoking,” according to Siegel.

Wide Variation Across Countries

Lung cancer death rates among young women are highest in Hungary (14.8 out of 100,000) and lowest in Costa Rica (0.7 out of 100,000), across the 65 countries analyzed. For older women, rates are highest in Scotland (120.0 out of 100,000) and lowest in Georgia and Egypt (8.8 out of 100,000). In general, for both younger and older women lung cancer death rates are highest in parts of Europe and North America and lowest in Africa, Asia, and Latin America.