Tobacco smoking has been linked to approximately two million deaths among adult men and women in Asia in recent years, according to a new study.
Researchers at Vanderbilt University (Nashville, TN, USA), the Japanese National Cancer Center (Tokyo, Japan), and more than three dozen other medical centers performed pooled analyses of data from 1,049,929 participants in 21 cohorts in Asia to quantify the risks of total and cause-specific mortality associated with tobacco smoking. They then estimated smoking-related deaths among adults aged 45 years and older in Bangladesh, India, mainland China, Japan, the Republic of Korea, Singapore, and Taiwan, which account for about 71% of Asia's total population.
The researchers found an approximately 1.44-fold and 1.48-fold elevated risk of death from any cause in male and female ever-smokers, respectively. In 2004, active tobacco smoking accounted for approximately 15.8% and 3.3% of deaths, respectively, in men and women in the seven regions combined, with a total number of estimated deaths of 1,575,500. The risk of death due to any disease varied considerably across populations, with the stronger association generally found in Japan, South Korea, Singapore, and Taiwan compared to that observed in mainland China and India.
Among men, approximately 11.4%, 30.5%, and 19.8% of deaths due to cardiovascular disease (CVD), cancer, and respiratory diseases, respectively, were attributable to smoking. The corresponding proportions for East Asian women were 3.7%, 4.6%, and 1.7%. Overall, the strongest association with tobacco smoking was found for lung cancer; a 3- to 4-fold elevated risk, accounting for 60.5% and 16.7% of lung cancer deaths, respectively, in Asian men and East Asian women aged 45 years and older. The study was published on April 22, 2014, in PLoS Medicine.
“Our study showed a clear dose-response relationship between the length of time someone smoked and the number of packs they smoked, known as pack-years, and the risk of death from all causes,” said lead author Professor Wei Zheng, MD, PhD, MPH, director of the Vanderbilt Epidemiology Center. “Tobacco smoking has now reached epidemic proportions in Asia and it is likely, with the maturation of this epidemic, and the lack of effective tobacco control efforts, smokers will continue to face an increased risk of death from cancer and other diseases.”
The ongoing global epidemic of tobacco smoking and tobacco-related diseases initially affected people living in the US and other Western countries, where the prevalence of smoking in men began to rise in the early 1900s, peaking in the 1960s. A similar epidemic occurred in women about 40 years later. By the 1990s, tobacco smoking accounted for a third of all deaths and about half of cancer deaths among men in the US and other Western countries. More recently, increased awareness and the introduction of various tobacco control measures has led to a steady decline in tobacco use and in smoking-related diseases.
Unfortunately, poorer tobacco control programs, inadequate public awareness of smoking risks, and tobacco company marketing have led to sharp increases in the prevalence of smoking in many low- and middle-income countries, particularly in Asia. More than 50% of men in many Asian countries are now smokers, about twice the prevalence in many Western countries, and more women in some Asian countries are smoking than previously.
Japanese National Cancer Center