Asian countries are in the early stages of a tobacco smoking epidemic with habits mirroring those of the US from past decades -- setting the stage for a spike in future deaths from smoking-related diseases, warn researchers.

Using long-term data from cohort studies from mainland China, India, Japan, South Korea, Singapore and Taiwan, the researchers from the Vanderbilt University Medical Centre in Nashville, Tennessee, said that future deaths were likely to echo the pattern that occurred in the US as the popularity of smoking increased during and after World War II, which resulted in lung cancer mortality peaking around 1990.

"There is about a 30-year gap or incubation period for the mortality to occur. Smoking takes about 20 or 30 years to have this full effect on lung cancer mortality," said Zheng, the study's senior author in a paper published in the journal JAMA Network Open. Tobacco control interventions may be having an effect on the smoking epidemic in some countries or areas because male smokers in the most recent birth cohort tended to quit smoking at younger ages.

"Asian countries that are richer, like Japan, South Korea and urban China, are doing a better job with this than rural China, India and other places," said Danxia Yu, co-first author of the study. The study calls for immediate actions for all Asian countries to implement comprehensive tobacco control policies, including raising tobacco taxes, implementing laws for smoke-free areas, banning tobacco advertising, requiring warning labels for tobacco products and providing help with quitting.

"Younger people in more recent cohorts started smoking at a younger age, and they smoked a lot more," Zheng said. "The deaths due to tobacco smoking also increased with this cohort." Women in Asia have a much lower rate for smoking. The average percentage of women smokers for all 20 cohort studies was 7.8 per cent compared to 65.4 per cent for men, the study noted.