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Background The major decrease in exposure to secondhand smoke (SHS) in public places in recent decades could have contributed to the decline in smoking-related cancer mortality observed in the US population. Methods Prospective study among 11,856 non-smoking adults aged ≥40 years who participated in NHANES 1988–1994 or 1999–2004 and were followed for mortality through 2006. We estimated the amount of change in cancer mortality over time attributed to the intermediate pathway of changes in SHS exposure in public places, after adjustment for risk factors and SHS exposure at home. Results The adjusted smoking-related cancer mortality rate ratios (95% CI) for a two-fold increase in serum cotinine and a 1-hour increase in occupational SHS exposure time were 1.10 (1.03, 1.17) and 1.14 (1.06, 1.24) for all-cancer, and 1.13 (1.03, 1.24) and 1.14 (1.02, 1.26) for smoking-related cancer, respectively. The absolute reduction in mortality comparing 1999–2004 to 1988–1994 was 75.8 (−25.5, 177.0) and 77.0 (2.6, 151.4) deaths/100,000 person-years, for all-cancer and smoking-related cancer, respectively. Among these avoided all-cancer deaths, 45.8 (2.8, 89.5) and 18.1 (−1.2, 39.6)/100,000 person-year were attributable to changes in serum cotinine concentrations and occupational SHS exposure time, respectively. The corresponding numbers of smoking-related cancer avoided deaths were 36.4 (0.7, 72.8) and 9.9 (−3.8, 24.9)/100,000 person-year. Conclusions Declines in SHS exposure were associated with reductions in all-cancer and smoking-related cancer mortality, supporting that smoking bans in public places may have reduced cancer mortality among non-smoking adults. [ABSTRACT FROM AUTHOR]

The severe air pollution across China in the past several years has made the Chinese government recognize its significant impacts on public health and society, and take enormous efforts to improve the air quality all over the country, especially during the Twelfth Five-Year Plan (12th FYP). However, the overall effectiveness of these air pollution control policies remains unclear. In this study, we selected the 31 municipalities and provincial capital cities in mainland China as study settings. We collected the annual average population size, mortality rates (total mortality and mortality due to cardiovascular diseases, respiratory diseases, total cancer, lung cancer and breast cancer) and concentrations of air pollutants (PM 10 , PM 2.5 , SO 2 and NO 2 ) in each capital city from 2010 to 2015 from national or local Statistical Yearbooks. The effect sizes of air pollutants on mortality were obtained from previously published meta analyses or cohort studies. We first estimated the annual mortality rates attributed to the changes in air pollutant concentrations for every city in each year. Then, we further estimated the mortality benefits in the scenarios where the air quality had reached the grade II levels of Chinese Ambient Air Quality Standards (CAAQS) and World Health Organization (WHO) guidelines. In most capital cities, we observed dominant decreases in air pollutant concentrations during the 12th FYP, particularly from 2013 to 2015, which has led to significant mortality benefits for the public. A total of 121,658 deaths (0.441‰) have been prevented due to the decrease of PM 2.5 concentrations from 2013 to 2015 in all included cities. The morality benefits were larger in capital cities located in the key regions (the three main regions and ten city groups) than the other cities. In addition, more mortality benefits could be obtained in the future if the air quality reaches the grade II levels of Chinese Ambient Air Quality Standards (CAAQS) or WHO guidelines. We concluded that substantial mortality benefits achieved during the 12th FYP may be attributed to the improvements in China's air quality, which indicated the significant effectiveness of air pollution control policies. [ABSTRACT FROM AUTHOR]