From the Guidelines
Yes, Japan has lower rates of lung cancer compared to the US, with the incidence of and mortality rates for lung cancer in Japan being consistently lower than those for Western countries, despite higher prevalence of cigarette smoking amongst Japanese men. According to the study published in the Annals of Oncology 1, this phenomenon is known as the "Japanese Lung Cancer Smoking Paradox". The study suggests that the lower rates of lung cancer in Japan can be attributed to various factors, including differences in smoking habits, diet, genetic factors, and environmental exposures. For instance, the Japanese diet, which is rich in fish, vegetables, and soy products, may provide protective effects against lung cancer development. Additionally, genetic factors may play a role, as some studies suggest that certain Asian populations might have different susceptibilities to tobacco carcinogens.
Some key points to consider include:
- The age-standardized incidence rate of lung cancer in Japan is lower compared to Western countries, including the US 1.
- The prevalence of cigarette smoking amongst Japanese men has been consistently higher than amongst their Western counterparts, yet the incidence of and mortality rates for lung cancer in Japan have been consistently lower 1.
- The Japanese diet and genetic factors may contribute to the lower rates of lung cancer in Japan, as well as differences in environmental exposures such as air pollution levels and occupational exposures.
- Smoking cessation remains the most effective preventive measure for lung cancer, regardless of location 1.
It is essential to note that lung cancer remains a significant health concern in both Japan and the US, and continued efforts to reduce smoking rates and promote healthy lifestyles are crucial to reducing the burden of this disease. The study published in the Annals of Oncology 1 provides further evidence of the importance of addressing lung cancer in Asia, where 51% of the world's lung cancer cases occur.
From the Research
Lung Cancer Rates in Japan and the US
- The study 2 found that lung cancer mortality rates in Japan were lower among current smokers and higher among non-smokers compared to the US.
- The relative risk of lung cancer associated with cigarette smoking was reported to be lower in Japan than in Western countries, including the US 2, 3.
- A case-control study 3 found that the odds ratio for lung cancer in current smokers relative to non-smokers was significantly higher in American men than in Japanese men.
- Another study 4 developed a conceptual model for lung cancer rates and found that the risk of lung cancer is less in Japan than in Sweden and the US at the same smoking prevalence and intensity.
Trends in Lung Cancer Mortality
- A study 5 found that Japan's initially lower male lung cancer mortality rate is now comparable to that in non-Asian countries, including the US, due to a slower decline in mortality rates.
- The age-adjusted mortality rate of lung cancer in Japan increased since 2000, but has been decreasing in recent years, similar to trends in other countries, including the US 6.
- Global age-adjusted lung cancer mortality rates have been declining in all countries, including Japan and the US 6.
Smoking Prevalence and Lung Cancer Risk
- The study 2 found that current smokers in Japan initiated smoking at an older age and smoked fewer cigarettes per day for shorter durations than those in the US.
- The risk of lung cancer associated with cigarette smoking was substantially higher in US men than in Japanese men, consistent with population-based statistics on smoking prevalence and lung cancer incidence 3.
- Possible explanations for the difference in risk include differences in cigarette formulation, filter type, and genetic susceptibility, as well as lifestyle factors other than smoking 3.