|Year : 2011 | Volume
| Issue : 3 | Page : 210-219
Exposure to tobacco smoke among adults in Bangladesh
Krishna Mohan Palipudi1, Dhirendra N Sinha2, Sohel Choudhury3, Zaman Mustafa4, Linda Andes1, Samira Asma1
1 Global Tobacco Control, Office on Smoking and Health, Centers for Disease Control and Prevention,
2 Global Tobacco Control, Office on Smoking and Health, World Health Organisation,
3 National Heart Foundation Hospital and Research Institute, Dhaka, Bangladesh,
4 Country Office for Bangladesh, World Health Organization,
|Date of Web Publication||16-Nov-2011|
Krishna Mohan Palipudi
Global Tobacco Control, Office on Smoking and Health, Centers for Disease Control and Prevention, Atlanta, GA 30345
| Abstract|| |
Objective: To examine exposure to second-hand smoke (SHS) at home, in workplace, and in various public places in Bangladesh. Materials and Methods: Data from 2009 Global Adult Tobacco Survey (GATS) conducted in Bangladesh was analyzed. The data consists of 9,629 respondents from a nationally representative multi-stage probability sample of adults aged 15 years and above. Exposure to second-hand smoke was defined as respondents who reported being exposed to tobacco smoke in the following locations: Indoor workplaces, homes, government building or office, health care facilities, public transportation, schools, universities, restaurants, and cafes, coffee shops or tea houses. Exposure to tobacco smoke in these places was examined by gender across various socioeconomic and demographic sub-groups that include age, residence, education and wealth index using SPSS 17.0 for complex samples. Results: The study shows high prevalence of SHS exposure at home and in workplace and in public places. Exposure to SHS among adults was reported high at home (54.9%) (male-58.2% and female-51.7%), in workplace (63%) (male-67.8% and female-30.4%), and in any public place (57.8%) (male-90.4% and female-25.1%) 30 days preceding the survey. Among the public places examined exposure was low in the educational institutions (schools-4.3%) and health care facilities (5.8%); however, exposure was high in public transportation (26.3%), and restaurants (27.6%). SHS exposure levels at home, in workplace and public places were varied widely across various socioeconomic and demographic sub-groups. Conclusions: Exposure was reported high in settings having partial ban as compared to settings having a complete ban. Following the WHO FCTC and MPOWER measures, strengthening smoke-free legislation may further the efforts in Bangladesh towards creating and enforcing 100% smoke-free areas and educating the public about the dangers of SHS. Combining these efforts can have a complementary effect on protecting the people from hazardous effect of SHS as well as reducing the social acceptance of smoking both at home and in public and workplaces. Ongoing surveillance in Bangladesh is necessary to measure progress towards monitoring SHS exposure.
Keywords: Prevalence, Second-hand smoke, Bangaladesh, Global Adult Tobacco Survey
|How to cite this article:|
Palipudi KM, Sinha DN, Choudhury S, Mustafa Z, Andes L, Asma S. Exposure to tobacco smoke among adults in Bangladesh. Indian J Public Health 2011;55:210-9
|How to cite this URL:|
Palipudi KM, Sinha DN, Choudhury S, Mustafa Z, Andes L, Asma S. Exposure to tobacco smoke among adults in Bangladesh. Indian J Public Health [serial online] 2011 [cited 2014 Apr 23];55:210-9. Available from: http://www.ijph.in/text.asp?2011/55/3/210/89942
Disclaimer: The views expressed in this article are not necessarily those of the GATS partner organizations.
| Introduction|| |
Second-hand smoke (SHS) is a mixture of thousands of chemical constituents, most of which are harmful and cause serious disease and death in the non-smoking population. A growing body of literature has demonstrated the harmful health effects of second-hand smoke exposure.  Exposure to tobacco smoke was estimated to have caused 379,000 deaths from ischemic heart disease, 165,000 from lower respiratory infections, 36,900 from asthma, and 21,400 from lung cancer.  More than 600 000 deaths per year worldwide were caused by second-hand smoke (SHS) in 2004,  which was about 1% of worldwide mortality. , Of the 603 000 deaths, 47% occurred in women, 28% in children, and 26% in men.  Studies on the impact of effective implementation of smoke free policies clearly indicate 10-20% reduction in acute coronary events in the first year post ban. ,
Article 8 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC)  calls for protection from exposure to tobacco smoke in indoor workplaces, public transportation, indoor public places, and as appropriate, other public places by adopting and implementing effective legislative, executive, administrative and other measures. In 2004, Bangladesh ratified the WHO FCTC. In addition, Bangladesh passed a comprehensive tobacco control law in line with the WHO FCTC. The Bangladesh Tobacco Control Act 2005  prohibits smoking in public transportation and public places such as educational institutions, government, semi-government and autonomous offices, libraries, lifts, hospitals and clinics, court buildings, railway stations, bus terminals, ferries, cinema halls, covered exhibition centers, theatres, shopping centers, public toilets, government administered and private children's parks and any or all other places where people could be exposed. However, these bans are partial as they do not comply with the stipulated policy. In 2006, rules were passed to facilitate the enforcement of laws and further formulated declaring schools and health settings as 100% smoke free. The Government of Bangladesh made a taskforce at national and sub national levels for implementation of tobacco control policies. To help countries fulfill their WHO FCTC obligations, in 2008 WHO introduced the MPOWER package of six evidence-based tobacco control measures that are proven to reduce tobacco use and save lives.  The MPOWER measures provide practical assistance with country-level implementation of effective policies to reduce the demand for tobacco. ,
Global surveys among youth and health professionals indicate exposure to SHS is high. Data from the Global Youth Tobacco Survey (GYTS) in Bangladesh indicated that more than 34% of students aged 13-15 years were exposed to SHS in their homes and more than 40% exposed in public places.  Findings from the Global Health Professions Students Survey in Bangladesh show that more than 75% of third-year medical and dental students were exposed to SHS in public places.  However, at national level, no study reported data on levels of SHS exposure among adult population in Bangladesh. Global Adult Tobacco Survey (GATS), for the first time, provided an opportunity to measure exposure to SHS among adults from nationally representative data using a standard protocol across various low and middle income countries.
This paper provides information on extent of exposure to SHS in homes, workplaces and different public places by various population subgroups. This paper examines the current levels of exposure to SHS in indoor workplaces, homes, government building or office, health care facilities, public transportation, schools, universities, restaurants, and cafes, coffee shops or tea houses in the past 30 days preceding the survey among adults age 15 years and above. Additionally, data was analyzed for smokers and non-smokers separately to understand the level of SHS exposure in these public places.
| Data and Methods|| |
GATS is a nationally representative household survey of men and women aged 15 years and above designed to produce internationally comparable data on tobacco use and tobacco control measures using a standardized questionnaire, sample design, data collection and management procedures and provided cross-sectional estimates for the country as a whole as well as by urbanicity (rural/urban) and gender. The GATS questionnaire in Bangladesh includes information on respondents' background characteristics, tobacco use (smoking and smokeless), cessation, second-hand smoke, economics, media, and knowledge, attitudes and perceptions towards tobacco use. In Bangladesh, a three-stage geographically clustered sample design was used to produce nationally representative data. One individual was randomly chosen from each selected household to participate in the survey. Survey information was collected using handheld devices. Due to non-proportional allocation of the sample to the different strata, appropriate sample weights were computed to ensure the actual representativeness of the sample at the national level as well as at stratum level (urban/rural areas). The weight computed for each respondent data record was the product of the base weights, the non-response adjustment and post-stratification calibration adjustment. The sample weights were used in all analyses to produce estimates of population parameters.
Variables included in the analyses
The second-hand smoke section of the questionnaire collects information from all adults on exposure to tobacco smoke in various public places that include indoor workplaces, homes, government building or office, health care facilities, public transportation, schools, universities, restaurants, and cafes, coffee shops or tea houses in the past 30 days preceding the survey. All these questions were analyzed in this paper to explore the prevalence of second-hand smoke exposure. As outlined in the GATS indicators guidelines,  second-hand smoke in this paper is defined for each place as the persons who reported being exposed to tobacco smoke in each place in the past 30 days. These indicators provide a measure of exposure to tobacco smoke across adult's age 15 years and above and represent the population level exposure. The respondents have been asked to respond if they saw somebody smoke or smelled the smoke inside the place (enclosed indoor areas) of interest.
Exposure to SHS in this paper was assessed in three different environmental contexts: At home, in indoor workplaces, and any public place. The indicator on exposure to SHS at home is defined as the percentage of adults who reported being exposed to smoke at home at least monthly. Exposure to second-hand smoke at work is defined as the percentage of indoor workers who were exposed to tobacco smoke in work place in the past 30 days. Indoor workers are classified as the respondents who work outside of the home who usually work indoors or both indoors and outdoors. Exposure to second-hand smoke in public places is defined as the number of respondents who reported being exposed to tobacco smoke in various locations/ public places in the past 30 days. The public places included indoor workplaces, homes, government building or office, health care facilities, public transportation, schools, universities, restaurants, and cafes, coffee shops or tea houses. A separate indicator was also computed for each of the locations mentioned above and was presented in separate sections. An additional analysis was carried out for smokers and non-smokers to understand the extent of exposure among males and females separately.
Relevant respondent variables considered in the analyses are respondent's age, place of residence (urban/rural), gender (male/female), educational level, and wealth index. GATS collected information on respondent's highest level of completed education. For the purpose of this paper, the question on educational level was grouped into five categories: No formal schooling, less than primary, primary complete, less than secondary, and secondary school complete and above (includes high school, college/university, and post graduate and above education). Wealth index, a proxy measure for respondent socioeconomic status, was constructed using principal component analysis , with information on household ownership of assets. The index used here was similar to the one developed and tested in a large number of countries in relation to inequities in household income. , It is an indicator of the level of wealth that is consistent with expenditure and income measures. , The asset information collected in GATS includes household ownership of a number of items, such as electricity, flush toilet, fixed telephone, cell telephone, television, radio, refrigerator, car, moped/scooter/motorcycle, washing machine, bicycle, sewing machine, almirah/ wardrobe, table, bed or cot, chair or bench, watch or clock, as well as the type of main material used for the roof of the main house (cement, tin and katcha such as bamboo / thatched / straw). The sample was then divided into quintiles from one being lowest to five being highest.
There were a total of 9629 completed interviews with an overall response rate of 93.6%. From the 9629 respondents, 4,468 were males and 5,161 were females, where as 4,772 were from the rural areas (73.3%) and 4, 857 from urban areas (26.7%) of Bangladesh.  Weighted distribution of the sample indicate that 29.5% of adults were in the age group 15-24 followed by 23.5% in the age group 25-34 years, 19.6% in the age group 35-44, 12.8% in the age group 45-54, 8.0% in the age group 55-64, and 6.6% in the age group 65 years and above. By education, 35.6% of all respondents had no formal education, 15.7% had less than primary education, 12.3% had primary education, 21.6% had less than secondary education, and 14.8% had completed secondary and above education. As per the wealth index quintiles, 18.8% of the respondents belong to lowest socioeconomic status, followed by 23.2% were in low, 20.4% were in middle, 22.6% were in high, and only 15.0% of respondents were in highest socioeconomic status. Confidence intervals (95% CI) were reported along with prevalence in percentages for all the estimates. Statistical significance tests (Chi-square) were used to assess the association between exposure to SHS and various socioeconomic and demographic sub-groups that include age, residence, education and wealth index by gender using SPSS 17.0 software for complex samples.
| Results|| |
Exposure to SHS at home
Overall 55% of adults reported that they had been exposed to SHS at home in the past 30 days [Table 1]. In general, males (58.2%) have reported a significantly higher exposure to SHS than females (51.7%). The pattern was similar when looked at the levels of exposure between smokers and non-smokers separately in both male and female [Figure 1]. However, there is no significant variation observed in exposure to SHS at home between male and female in various socioeconomic categories. Urban populations have higher levels of exposure to SHS at home compared to rural populations. SHS exposure at home did not vary by age, however middle aged adults reported higher levels of exposure (58.3% in the 35-44 age group and 56.2% in the 45-54 age group). As educational attainment increases the percent exposed to SHS decreases. Exposure to SHS at home is significantly higher among adults with no formal schooling (64%) compared to adults with high education (37%). Similar levels of exposure are reported by both male and female in the respective education categories. Similar to education, adults from lowest socioeconomic status reported a higher level of SHS exposure at home than the adults in the highest socioeconomic categories.
|Table 1: Second-hand smoke exposure among adults age 15 years and above at home, in workplace and in any public place in the past 30 days preceding|
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|Figure 1: Exposure to second-hand smoke at home, workplace and any public place by gender and smoking status in Bangladesh|
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Exposure to SHS in work place
Overall 52% reported that they had been exposed to SHS in indoor workplaces [Table 1]. Exposure to SHS at work was higher among men (67.8%) than women (30.4%). Similar to the overall exposure levels among Bangladeshi adults, the prevalence of exposure at the work place was higher for men in both smokers as well as non-smokers separately (75.6% and 91% respectively), but the level of exposure was much higher among female smokers who usually work indoors or both indoors and outdoors [Figure 1]. More adults from rural areas (66%) are exposed to SHS than the adults from urban areas (58.7%). Irrespective of the age, adult males are more exposed to SHS than females, though middle aged adults reported a higher level of exposure at workplace in the last 30 days (66.6% in 35-44 age group and 67.8% in 45-54 age group). The adults with no formal schooling (71%) tend to be expose more than the adults with secondary school and above (49%) education. Adults with lowest wealth index (66%) reported a higher exposure than that of highest wealth index (59%), though this was not significant.
Exposure in public places
Tobacco smoke exposure in any public place
Second-hand smoke exposure in any public place represents a combined measure of exposure in either of the places mentioned above. Among Bangladeshi adults 58% reported exposure to SHS in any of the public places in the past 30 days preceding the survey [Table 1]. The exposure at any public place is significantly higher among males (90.4%) than females (25.1%) and the gender specific differences are observed across all the socioeconomic and demographic subgroups. Similar to workplaces and at homes, middle aged adults (aged between 35 and 64) reported higher levels of exposure to SHS in any public places. Among male, education did not play a role in explaining the differences; for educational level exposure among female ranges between 21.1% and 35.6%No significant differences are observed with respect to wealth index. However, there is a gradient between lowest and middle though not significant between low and middle. When looking at the level of exposure in any public place separately for smokers and non-smokers, prevalence was almost four times higher among male compared to female. However interestingly, female non-smokers (25.1%) reported a higher level of exposure compared to female smokers (22.5%) [Figure 1].
Tobacco smoke exposure in specific public place
For specified locations [Table 2] in the month preceding the survey, exposure to SHS was lowest (range between 1.5% to 5.8%) in the universities (1.5%), schools (4.3%), private workplaces (4.3%), government buildings or offices (5.4%), and health care facilities (5.8%), The public places with highest reporting of SHS exposure were (range between 26.3% to 43.3%) in public transportation (26.3%), restaurants (27.6%), and cafes, coffee shops or tea shops (43.3%) [Table 2]. Strong gender differences (a low level of exposure among female) were observed in these public places. There are no urban, rural differences observed in any specific location expect for private workplaces where urban adults reported higher levels of exposure to SHS and adults in rural areas reported higher levels of exposure to SHS in government building or offices, and universities. Irrespective of the location, adults in middle ages (ages between 35 and 64) reported higher levels of exposure to tobacco smoke except in schools and universities where a majority of adults tend to visit these places during younger ages. Interestingly, education is showing a positive gradient with respect to exposure to tobacco smoke i.e. adults with no formal schooling have reported a low level of exposure compared to the adults with high education (secondary school and above), particularly in government building or offices, health care facilities, public transportation, schools, universities and restaurants. A similar pattern is observed with respect to socioeconomic status of the respondents where adults reported a higher level of exposure to tobacco smoke when they belong to highest level of socioeconomic status. For example, the level of exposure to SHS among adults with high socioeconomic status is 5.5% in schools, 4.9% in universities, 12.7% in government buildings or offices, 8.3% in health care facilities 36.9% in restaurants, and 9.7% in private workplaces as compared to 2% in schools, 0.3% in universities, 3.5% in government buildings or offices, 4.3% in health care facilities, 22.7% in restaurants, and 2.3% in private workplaces with lowest socioeconomic status.
|Table 2: Second-hand smoke exposure among adults age 15 years and above in specific public places in the past 30 days preceding the survey|
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| Discussion|| |
Over half of Bangladeshi adults were exposed to SHS in homes and public places and nearly two thirds of adults are exposed to SHS in workplaces. Of these, nearly 7 in 10 men at work places and 9 in 10 men at public places are exposed to SHS. The high levels of exposure to SHS, particularly in middle ages, will further add to chronic disease burden and premature death in productive age group in Bangladesh. Thus following the WHO FCTC  and MPOWER  strategies for further strengthening smoking ban policies and its effective enforcement is important to prevent premature deaths  in Bangladesh. Over 50% of adult women in Bangladesh are exposed to SHS in homes and lower levels of exposure among women compared to men in all the public places suggest that female who are housewives and unemployed less likely to visit these public places. Higher levels of exposure in less educated adults augment the need for awareness about the dangers of SHS in non-smokers as many nonsmokers are also not aware of the dangers of second-hand smoke. , The extreme addictive nature of tobacco is also not widely acknowledged.  This finding demands equitable public health initiatives to educate all sections of people, particularly women, through appropriate programmes. Exposure to SHS among females in homes is attributable to high smoking prevalence among men, poor living in single dwelling homes and lack of knowledge on harmful effects of SHS on non smokers.
Physically separating smokers from non-smokers by allowing smoking only in designated smoking rooms reduces exposure to second-hand tobacco smoke only by about half, and thus provides only partial protection.  Scientific evidence has unequivocally established that 100% smoke-free environments are the only proven way to fully protect the health of people from the harmful effects of second-hand tobacco smoke. ,,, Bangladesh has 100% smoke-free policy for health facilities and educational institutions, but not for other public places.  Findings from GATS suggest that relatively low levels of exposure to SHS in schools (4.3%), and health settings (5.8%), as compared to other public places such as restaurants (27.6%), public transport (26.3%), for which policy does not provide 100% smoke-free policy. Completely smoke-free environments are the only proven way to protect people adequately from the harmful effects of second-hand smoke. Smoke-free environments not only protect non-smokers they also help smokers who want to quit. 
The data from this report clearly indicates that smoke free policy needs to be strengthened by declaring more and more public places 100% smoke free in Bangladesh. Awareness campaigns through effective public education, media advocacy and communication is the key to implement smoke-free policies. Governments and communities need to work together to create smoke-free environments. Appropriate strategies need to be developed to involve the private sector and communities to ensure success for the campaign for smoke-free environments. In Bangladesh, 43.3% of adults (41.3 million) currently use tobacco in smoking and/or smokeless form. , Among adults aged 15 years and above, 44.7% of men, 1.5% of women, and 23.0% overall (21.9 million adults) currently smoke tobacco in Bangladesh. , Out of all tobacco smokers, 14.2% (28.3% male and 0.2% female) were current cigarette smokers and 11.2% (21.4% male and 1.1 female) were current bidi smokers. , Increasing taxation will not only help tobacco users quit and reduce the number of new tobacco users, but also protect people from second-hand smoke.  Ongoing surveillance in Bangladesh is necessary to monitor implementation of tobacco control measures including SHS exposure through cost effective and sustainable systems. Bangladesh has made a task force to implement smoke free policies which needs to be further strengthened and functioning in collaboration with community participation.
The findings in this report are subject to the limitation that the prevalence results are based on self-reports. In certain settings, social norms (i.e., unacceptability of women smoking or going to work or visiting various public places) might result in underreporting. Furthermore, education categories were combined into broad groupings, which could have contributed to biased estimates in terms of the gradients observed. Nonetheless, these groupings provided greater precision than those used in earlier tobacco use research in Bangladesh. The data used in constructing wealth index is based on limited number of asset variables which might result in incomplete or under representing socioeconomic status. Finally, some of the public places included in the analysis may be considered work places or public places or both for some respondents.
| Acknowledgements|| |
The authors would like to thank Bangladesh Ministry of Health and Family Welfare, Bangladesh Bureau of Statistics (BBS), National Institute of Preventive and Social medicine (NIPSOM), National Institute of Population Research and Training (NIPORT), World Health Organization (WHO) country office for Bangladesh who made completion of the GATS possible. Funding for the Global Adult Tobacco Survey (GATS) is provided by the Bloomberg Initiative to Reduce Tobacco Use, a program of Bloomberg Philanthropies
| References|| |
|1.||Besaratinia A, Pfeifer GP. Second-hand smoke and human lung cancer. Lancet Oncol 2008;9:657-66. |
|2.||Oberg M, Jaakkola MS, Woodward A, Peruga A, Prüss-Ustün A. Worldwide burden of disease from exposure to second-hand smoke: A retrospective analysis of data from 192 countries. Lancet 2011;377:139-46. |
|3.||Wipfli HL, Samet JM. Second-hand smoke's worldwide disease toll. Lancet 2011;377:101-2. |
|4.||World Health Organization (WHO). Framework Convention on Tobacco Control. WHO Press, Geneva, WHO, 2003. (Available from: http://whqlibdoc.who.int/publications/2011/9789241501316_eng.pdf). [Last accessed on 2011 Mar 07]. |
|5.||Government of Peoples Republic of Bangladesh, Ministry of Health and Family Welfare. Smoking and Tobacco Products Usage (Control) Act. Act, 2005. Dhaka, 2005. (Available from: http://www.searo.who.int/LinkFiles/Legislation_and_Policy_Bangladesh_legislation_english.pdf). [Last accessed on 2011 Mar 07]. |
|6.||WHO. MPOWER: A policy package to reverse the tobacco epidemic. WHO press, Geneva, WHO, 2008. (Available from: http://www.who.int/tobacco/mpower/mpower_english.pdf). [Last accessed on 2011 Mar 07]. |
|7.||WHO. WHO report on the global tobacco epidemic 2011: Warning about the dangers of tobacco. Geneva, WHO, 2011. (Available from: http://whqlibdoc.who.int/publications/2011/9789240687813_eng.pdf). [Last accessed on 2011 Mar 07]. |
|8.||WHO. Regional Office for South-East Asia. Report on Global Youth Tobacco Survey (GATS) and Global School Personal Survey (GSPS), Bangladesh. Dhaka, 2008. (Available from: http://www.searo.who.int/LinkFiles/GYTS_BAN2007.pdf). [Last accessed on 2011 Mar 07]. |
|9.||WHO. Regional Office for South-East Asia. Global Health Professions Students Survey (GHPSS)-Fact Sheet, Bangladesh. Dhaka, Bangladesh, 2009. (Available from: http://www.searo.who.int/LinkFiles/GHPS_Factsheet_Ban.pdf). [Last accessed on 2011 Mar 07]. |
|10.||Global Tobacco Surveillance System (GTSS). Global Adult Tobacco Survey (GATS): Indicator Guidelines: Definition and Syntax. Atlanta, USA, 2009. (Available from: http://apps.nccd.cdc.gov/GTSSData/Ancillary/Documentation.aspx?SUID=4&DOCT=4). [Last accessed on 2011 Mar 07]. |
|11.||Rutstein S. Wealth versus expenditure: Comparison between the DHS wealth index and household expenditures in four departments of Guatemala. Calverton, Maryland: ORC Macro; 1999. |
|12.||National Institute of Population Research and Training (NIPORT), Mitra and Associates, and Macro International. Bangladesh Demographic and Health Survey 2007. Dhaka, Bangladesh and Calverton, Maryland, USA: National Institute of Population Research and Training, Mitra and Associates, and Macro International, 2007. |
|13.||Gwatkin DR, Rutstein S, Johnson K, Pande RP, Wagstaff A. Socio-economic differences in health, nutrition and poverty. HNP/Poverty Thematic Group of the World Bank. Washington, D.C.: The World Bank; 2000. |
|14.||Rutstein S, Johnson K, Gwatkin D. Poverty, health inequality, and its health and demographic effects. Paper presented at the 2000 Annual Meeting of the Population Association of America, Los Angeles, California, 2000. |
|15.||WHO, Country Office for Bangladesh. Global Adult Tobacco Survey: Bangladesh report. Dhaka, Bangladesh, WHO, 2009. (Available from: http://www.who.int/tobacco/surveillance/global_adult_tobacco_survey_bangladesh_report_2009.pdf). [Last accessed on 2011 Mar 07]. |
|16.||Office of Environmental Health Hazard Assessment. Health effects of exposure to environmental tobacco smoke. Sacramento, CA, California Environmental Agency, 1999. (Available from: http://www.oehha.org/air/environmental_tobacco/finalets.html). [Last accessed on 2011 Apr 12]. |
|17.||USDHSS. The health consequences of involuntary exposure to tobacco smoke: A report of the Surgeon General. Atlanta, GA, US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2006 (Available from: http://www.surgeongeneral.gov/library/second-handsmoke/report/index.html). [Last accessed on 2011 Apr 12]. |
|18.||Koh HK, Alpert HR, Judge CM, Caughey RW, Elqura LJ, Connolly GN, et al. Understanding worldwide youth attitudes towards smoke-free policies: An analysis of the Global Youth Tobacco Survey. Tob Control 2011;20:219-25. |
|19.||Warren CW, Sinha DN, Lee J, Lea V, Jones NR. Tobacco use, exposure to second-hand smoke, and cessation counseling among medical students: Cross-country data from the Global Health Professions Student Survey (GHPSS), 2005-2008. BMC Public Health 2005;11:72. |
|20.||WHO. Profile on Smoke-free Environments in the South-East Asia region. New Delhi, India, 2007. (Available from: http://www.who.int/tobacco/resources/publications/wntd/2007/searo_smoke_free_environment.pdf). [Last accessed on 2011 Apr 12]. |
|21.||Xiao L, Yang Y, Li Q, Wang CX, Yang GH. Population-based survey of second-hand smoke exposure in china. Biomed Environ Sci 2010;23:430-6. |
|22.||Cains T, Cannata S, Poulos R, Ferson MJ, Stewart BW. Designated "no smoking" areas provide from partial to no protection from environmental tobacco smoke. Tob Control 2004;13:17-22. |
[Table 1], [Table 2]