In addition to the collision between TB and tobacco epidemics in many developing nations, the prevalence of smoking among patients with TB is generally high [17, 19]. Previous studies suggest that a large proportion of patients with TB may be active smokers or involuntarily exposed to other people's tobacco smoke [12, 15–18, 24]. In the present study, we found that smoking prevalence rate was high among patients with TB in the State of Penang (current and ex-smoking rates of 40.27% and 13.95%, respectively). This rate is as high as those reported from other countries (35 - 86%) [12, 15, 18, 24–26]. Although the smoking rate in the current study is higher than the national average among the general adult population (21.5%), but it was somewhat lower than the male smoking rate in Malaysia (46.4%) . Our findings may largely reflect smoking rate among male TB patients, since they predominated the study population. However, the rates in our study might have been grossly underestimated due to the unknown smoking status of a reasonable proportion of the newly diagnosed TB patients who might as well be tobacco smokers. Furthermore, since we used self-reported smoking status, it is possible that the rates might have been under-recorded, which would mean that the prevalence of smoking among patients with TB would be even greater than observed. A systematic review has demonstrated a trend of underestimation when smoking prevalence is based on self-reports . One study from three West Africa countries (Guinea, Guinea Bissau, and The Gambia) reported that the smoking prevalence rate among TB cases was twice as high as among control household members (35% versus 17%, respectively) . In India, the prevalence of smoking was 3.5 times as high among patients with TB compared with controls (86% versus 24%) .
Therefore, efforts should be geared towards reducing tobacco use among this population due to its negative impact on TB treatment outcomes. In the light of the burden of TB association with tobacco smoking, patients need to be well-educated about tobacco use and its health dangers. They also need to have positive attitudes against tobacco smoking. Malaysian government has initiated mass media campaigns against tobacco use under the "Tak Nak" or "Don't Want" program. Yet substantial proportions of TB patients in the current study were either not sure or did not support the on-going government campaigns against tobacco use.
Understanding the tobacco use knowledge, attitudes and behaviors of TB patients is of significance in the provision of behavioral therapy for smoking cessation. In a cross-sectional study among former TB patients in Indonesia, more than 30% of them reported that they were never asked about their smoking behavior or advised about quitting . Such information will also be of value in designing effective educational intervention programs on motivating tobacco users to quit and urging non-users to avoid smoking. The educational programs can have an impact in the control and prevention of TB, treatment failure, relapse and poor prognosis. The mean total score of tobacco use knowledge of 4.23 (equivalent to 38.5%) found in this study suggests that newly diagnosed TB patients had poor knowledge of tobacco use. Although, the knowledge tested in the current study was about tobacco use and its health consequences in general, this finding points to possible deficits in knowledge specific to the association between tobacco smoke exposure and TB. Two recent studies conducted among ex-TB patients reported that the majority received only general health messages and not TB-specific messages [24, 26]. Such subjects seem to be ill-informed about the impact of continued smoking on TB. Therefore educational programs specific to the impact of tobacco smoke exposure on TB should be designed to educate TB patients who are smokers on the general health dangers of tobacco use as well as its negative impacts on TB. They should also be enlightened on the short- and long-term benefits of quitting smoking on TB treatment outcomes and future lung health. In the present study, patients in the stage of preparation for behavior change were significantly more knowledgeable than their counterparts who were still in the contemplation and pre-contemplation stages (5.38 vs. 3.73, respectively). Perhaps this reaffirms that their intention to quit may be associated with the knowledge they possessed. Those who had previous quitting experience also seemed to be more knowledgeable than their counterparts who had never attempted to do so.
In general the patients had positive attitudes against tobacco use. These findings are encouraging. For instance, the respondents generally believed that tobacco smoking is a waste of money and is very dangerous to health. They also admitted that the sales of cigarettes should be outlawed, people under 18 years of age should be restricted from buying cigarettes and that smoking should be allowed at fewer places than it were. In this study, the use of cigar, pipe, and smokeless tobacco (snuff) was not prevalent among TB patients who smoke cigarettes. Furthermore, most of the respondents started the behavior of using tobacco products other than cigarettes at the age of 20 years and above. This indicates that intervention programs on prevention of tobacco use should target younger age groups.
This study has a number of limitations. First, the tobacco use behaviors of patients with TB may be under- or over-estimated in the light of using self-reports without biochemical verifications. Secondly, the sample may not be representative of all TB patients who are smokers in Malaysia, since it was derived from only two states. Lastly, the evaluation of knowledge did not include items specific to the negative impact of tobacco smoking on TB.