Media coverage of tobacco-related issues can potentially shape individual beliefs, attitudes and behaviors about tobacco use [1]. Recent studies of tobacco control policy-making in several countries have demonstrated that mass media play an indispensable role in advocacy and support for law reform in tobacco control [2–6]. Efforts to increase news media coverage of both personally relevant and policy-oriented matters have therefore become a key part of comprehensive tobacco control programs [7].

With the world's largest population, China has 52.4% of adult men and 3.4% of adult women smoking [8, 9]. Although the Framework Convention on Tobacco Control (FCTC) has been in force in China since 2006, there was no national law prohibiting tobacco use in public settings until 2010. As of 2006, about 46% of Chinese cities had introduced laws on tobacco control [10]. Across the country, there are more than 800 tobacco cessation clinics, although little information is available about their utilization or cessation outcomes. In addition, a growing number of activities are underway to implement smoke-free hospitals, schools and communities. Under the encouragement of the central government, some provincial and city governments have passed local regulations to strengthen tobacco control in public places such as public transport, cinemas and hospitals.

Liu et al. reported in a letter that news coverage of tobacco issues in Chinese newspapers increased dramatically in recent years, from 43 articles in 2000 to 409 articles in 2008 [11]. However, their analysis did not take into account the growing number of newspapers included in the database in noting the reported increase, reported no coding reliability coefficient and also did not assess the "slant" of articles as to whether they were in support of or opposed to tobacco control.

This study sought to describe the changing pattern of newspaper coverage of tobacco control issues in China over a decade, including the principal issues relevant to tobacco control which were reported and the dominant viewpoints or slant on tobacco control in this coverage.

The Database of Chinese Important Newspapers http://www.cnki.net has indexed major Chinese newspapers since 2000. The database covered more than 500 newspapers, 7.95 million papers, cover 168 topics and 3600 subgroup until December 31, 2010. But not all newspapers were indexed in 2000; the number of newspapers indexed in the database has increased continually. So the increase of newspapers indexed in the database may confound the analysis of the growth of newspaper coverage. We therefore only searched news articles from 185 newspapers indexed continuously from January 1, 2000 to December 31, 2010(See additional file 1). The search keywords were fixed as 'xiyan'(smoking) OR 'xiangyan'(cigarettes) OR 'yancao'(tobacco) OR 'kong yan' (tobacco control), OR 'wu yan' (tobacco free) OR 'jin yan' (tobacco prohibition) with Chinese and English expansion. Each article obtained from the database was scrutinized to ensure that it related to tobacco control, and all without tobacco control related content were excluded. A total of 1149 articles published in 102 continually published newspapers were thus located and analyzed. This compared with Liu et al's 152 national and 363 local newspapers indexed at any point in their 2000-June 2008 study [11].

A total of 1149 articles related to tobacco control were located in the 102 newspapers tracked across the decade. There was a statistically significant difference in the number of articles appearing each year (p < 0.001). From 2000 to 2004, an average of just 36 articles was published across all newspapers every year. In 2005, the number reached 61, and grew continuously until 2008, when 209 were published. 2009 saw a small fall (n = 191). And in 2010, 271 articles were published (Table 1). Similarly, there was a significant difference in the number of articles appearing each month (p < 0.001). More than 20% of all articles (20.2%, 232 articles) were published in May, and 13.6% (156 articles) were published in June, both being higher than in other months (Figure 1).

Policy type	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	Total
Monitoring	2(1.6)	0(0)	1(0.8)	2(1.6)	3(2.4)	3(2.4)	10(7.9)	20(15.9)	24(19.0)	17(13.5)	44(34.9)	126(11.0) *
Protection	7(2.4)	1(0.3)	2(0.7)	6(2.1)	2(0.7)	12(4.2)	11(3.8)	36(12.6)	62(21.7)	55(19.2)	92(32.2)	286(24.9) *
Offering help	0(0)	0(0)	0(0)	2(3.7)	1(1.9)	2(3.7)	7(13.0)	6(11.1)	15(27.8)	10(18.5)	11(20.4)	54(4.7) *
Warning	22(7.6)	18(6.2)	15(5.2)	22(7.6)	18(6.2)	24(8.2)	36(12.4)	34(11.7)	37(12.7)	45(15.5)	20(6.9)	291(25.3) *
Enforcement	3(2.9)	6(5.8)	3(2.9)	5(4.8)	5(4.8)	5(4.8)	5(4.8)	11(10.6)	6(5.8)	14(13.5)	41(39.4)	104(9.1) *
Raising taxes	0(0)	1(1.6)	1(1.6)	0(0)	1(1.6)	0(0)	6(9.5)	2(3.2)	14(22.2)	24(38.1)	14(22.2)	63(5.5) *
Youth access, purchase and possession	2(3.0)	1(1.5)	5(7.5)	3(4.5)	7(10.4)	10(14.9)	5(7.5)	9(13.4)	11(16.4)	5(7.5)	9(13.4)	67(5.8) *
Large scale smoke free activity	0(0)	0(0)	0(0)	0(0)	1(2.3)	0(0)	2(4.7)	9(20.9)	20(46.5)	2(4.7)	9(20.9)	43(3.7) *
Miscellaneous	2(1.7)	3(2.6)	4(3.5)	3(2.6)	2(1.7)	5(4.3)	8(7.0)	18(15.7)	20(17.4)	19(16.5)	31(27.0)	115(10.0) *
Total	38(3.3)	30(2.6)	31(2.7)	43(3.7)	40(3.5)	61(5.3)	90(7.8)	145(12.6)	209(18.2)	191(16.6)	271(23.6)	1149(100) *

*Poisson heterogeneity test p < 0.001

Overall, 24.9% (n = 286) of articles focused on protecting people from tobacco smoke, 25.3% (n = 291) focused on information about the dangers of tobacco, and 10% (n = 115) focused on prevention and cessation programs and campaigns. For each topic, there was a significant difference in the number of articles appearing each year (p < 0.001). Few were published before 2005, and then numbers increased sharply. For example, only five articles about cessation were published before 2006, with this increasing to 11 (20.4%) in 2010. The first article about smoke free events (smoke-free Olympics, smoke-free World Expo, and smoke-free Asian Games) appeared in 2004, with most (46.5%) published in 2008 when the Olympic Games were held in Beijing, 20.9% appeared in 2010 when World Expo held in Shanghai (Table 1).

Overall, 908 articles (79%) featured in national newspapers and 241 (21%) were published on local newspapers. There was a significant difference in the topics between the two article origins (χ ² = 24.094, df = 8, p = 0.002). So we conducted standardized residual analysis to identify what was driving this significant result. The national newspaper articles reported more on warning(27.0%) and enforcement(10.1%); less on monitoring(9.7%) and protection(23.8%), while the local articles reported more on monitoring(15.8%), protection(29.0%); less on warning(19.1%) and enforcement(5.0%).

There were 590 news stories (51.3%), 247 editorials (21.5%), 312 letters to the editor (27.2%). We found a significant association between tobacco control topic and article type (χ ² = 190.353, df = 16, p < 0.001). Standardized residual analysis indicated that news stories were more likely than expected focus on monitoring (18.8%) or smoke free activity (15.9%) and less likely to focus on enforcement(5.3%); editorials were more likely than expected to focus on enforcement(15.4%), youth access(9.3%) or programs and campaigns(6.1%), and less likely to concern smoke free activity(3.6%) or monitoring(4.9%). Letters to the editor were more likely than expected to concern warning(33.0%), enforcement(8.0%) or raising taxes(9.0%), and less likely to concern monitoring(1.0%) or programs and campaigns(0.6%). There were only 77 articles (6.7%) published on the front page. These focused on protection (37.7%) and monitoring (15.6%) and warning (13.0%).

There were 121 articles classified as pro-tobacco (10.5%), 449 neutral/balanced (39.1%) and 579 anti-tobacco (50.4%). Before 2004, the number of these three kinds of articles remained low. After 2004, anti-tobacco articles increased more sharply than pro- or neutral/balanced articles. In 2010, the number of anti-tobacco articles was twice as common as neutral/balanced articles and eight times more frequent than pro-tobacco articles (Figure 2).

There was a significant association between point of view and article origin (χ ² = 29.901, df = 2, p < 0.001), with national articles being more likely to express anti-tobacco views, while local articles were more likely to express pro-tobacco or neutral/balanced views (Figure 3).

Similarly, we also found a significant association between point of view and article type (χ ² = 268.91, df = 4, p < 0.001). News stories were more likely to express neutral/balanced points of view; editorials were more anti-tobacco, while letters to the editor were predictably more inclined both to pro-tobacco and anti-tobacco views (Figure 4).

News coverage plays a key role in shaping public and political attitudes about tobacco control [1]. Our findings suggest that Chinese newspapers paid little attention to tobacco control issues prior to 2005, but thereafter news attention increased, which was consistent with Liu's study finding [11]. Chinese newspapers are giving increasing attention to tobacco control, but coverage remains low in comparison to the USA and Australia [19–21]. There remains much potential for journalists, health workers and citizens to increase coverage of tobacco control matters in China.

Several developments were associated with the observed increase in reporting: the Chinese Government signed the WHO Framework Convention on Tobacco Control (FCTC) in 2003 and the Standing Committee of the National People's Congress ratified it in 2005; the 2008 Beijing smoke-free Olympics; the Notice on Adjusting Consumption Tax of Tobacco Products came into force on May 1, 2009 [22]; and the smoke-free World Expo was held in Shanghai in 2010. These all stimulated provincial and city governments to pass local bans prohibiting smoking in public settings, which attracted news attention. For example, the Notice on Adjusting Consumption Tax of Tobacco Products came into force in 2009, causing the number of articles about tobacco tax to reach peak (Table 1). Tobacco tax - arguably the most effective of all tobacco control strategies - is poorly covered in Chinese news media. A large population of Chinese smokers has low incomes and is likely to be price-sensitive. Future tobacco advocacy should target raising media attention to the strong positive effect of increasing tobacco tax on cessation.

As has been reported in other studies, the impact of special days focused on tobacco control [11, 23, 24] can generate spikes in media attention to tobacco control. However, when the year round coverage of tobacco control related issues is low as it is in China, concerns arise when journalists concentrate this coverage around just one day and publish relatively few stories during the rest of the year. Days like World No Tobacco Day can be important conduits for news attention, but they can also send an unfortunate message that attention to tobacco control is not a mainstream news area. Indeed, only 6.7% (n = 77 in 10 years) of articles were published on the front page, suggesting that tobacco control is seldom regarded by editors as a leading news issue.

Tobacco control advocates should learn how to harness the synergistic effects of national and local developments. In recent years, city development has been very fast in China. Advocates should make use of opportunities arising from large-scale city-image-building activities, and seek to encourage smoke free policies as integral to these.

It is encouraging that more than half of articles (50.4%) were anti-tobacco, with this proportion increasing across the decade. National articles were significantly more inclined to support tobacco control than were local articles. In China, national newspapers are usually sponsored by the central government, while local newspapers are sponsored by local government or their branches. Local economy protectionism may explain the discrepancy in the support shown for tobacco control between national and local media. Tobacco producers typically contribute significantly to local economies, and have close ties with local governments. Tobacco businesses may receive political support from local governments, including the publishing of stories supportive of the tobacco industry.

There are several limitations in this study. First, our analysis is limited to newspaper coverage of tobacco control issues. Newspapers are only one of many news outlets that may affect public opinion. But the coverage of issues in newspapers is typically highly correlated with the presentation of the same issues in other media such as radio and television [25], with morning newspapers often setting the agenda for coverage by other media during the day. Second, we coded tobacco control policy according to the categories of the WHO MPOWER package, which differ from previous research [4, 6, 15, 16] and may be not suitable comparing with that research. Two recent studies [10, 26] on implementation of the FCTC and MPOWER in China showed that tobacco control in China is relatively undeveloped and that there are large gaps in meeting FCTC standards. Finally, because we could not obtain the circulation of each newspaper from the database, we could not analyze how many people were reached and potentially influenced by the coverage we report.

Chinese newspapers are giving increasing attention to tobacco control, but coverage remains low by international benchmarks. Health workers need to give higher priority to efforts to increase news coverage beyond the present concentration around World No Tobacco Day and to develop strategies for making tobacco control issues more newsworthy to both national and local news outlets.