Research in context
Evidence before this study
We searched PubMed for articles published up to May, 2018, using the terms “smoking” OR “tobacco use” AND “chronic diseases” AND “trend” OR “prevalence” and retrieved a total of 14 324 papers. Among them, 866 papers included data from China. None of these papers reported nationwide trends of tobacco use and its association with chronic diseases in China after 2003. We also searched PubMed using (“smoking”[MeSH Major Topic] AND prevalence [Title/Abstract]) AND China [Title/Abstract]) and retrieved 242 articles. We identified six national surveys for smoking prevalence after 2003. Four surveys of Chronic Disease Risk Factor Surveillance in China were carried out in 2004, 2007, 2010, and 2013. Three of them surveyed individuals aged 18 years or older whereas only one surveyed individuals aged 15–69 years, meaning the trends of smoking prevalence in adolescents aged 15–18 years could not be well studied in these surveys. Two national surveys were carried out in 2010 and 2015 with a relatively smaller sample size of around 15 000 people, using the same survey method of the Global Adult Tobacco Survey (GATS). All surveys we found used an individual-based approach whereas our study used a household-based approach. We estimated familial aggregation by using multistage household cluster sampling. Only the 2010 GATS was reported on a global scale, whereas the other five surveys have not been reported globally. Researchers in the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 estimated daily smoking prevalence by sex and age group for 195 countries from 1990 to 2015. Additionally, Bilano and colleagues investigated smoking prevalence and cigarette consumption in 173 countries for men and 178 countries for women from 1980 to 2012. However, none of these studies explored the most recent trends of smoking prevalence and chronic disease burden in China. Moreover, all of them were either a single cross-sectional study or on the global scale instead of focusing on China.
Added value of this study
Our national study, covering all the provinces in mainland China and spanning from 2003 to 2013, presents the most recent patterns of smoking prevalence and its relationship with NCDs in China since the WHO FCTC launched globally. Our results show that smoking prevalence in China remained at a high plateau during the studied decade. The smoking prevalence in some regions was significantly higher than the national average. In particular, we show a rapid increase in smoking prevalence in adolescents in China. Moreover, our study indicated an increase in smoking prevalence in women younger than 40 years. We identified the number of older family members who smoke—especially when the family members are female—as a risk factor for smoking in adolescents. We show a non-linear, negative correlation between chronic diseases and smoking initiation age, suggesting that individuals who started smoking earlier had a higher risk of chronic diseases.
Implications of all the available evidence
China has failed to fulfil the WHO FCTC fully in the studied decade. The increase in smoking prevalence among adolescents and women, combined with the association of female family members who smoke with increased adolescent smoking prevalence, implies that the Chinese Government should establish more stringent policies and enforce the law more strictly, with a strong focus on stopping and reversing the increased prevalence in adolescents and women.