|EVIDENCE-BASED MEDICINE: SUMMARY OF STUDY
|Year : 2018 | Volume
| Issue : 1 | Page : 18-19
Low-Volume cigarette smoking is also harmful: Summary of study
Heber Rew Bright1, Ronald Carey2
1 Lecturer, Department of Pharmacy Services, Christian Medical College, Vellore, India
2 Associate Professor, Department of Medicine, Christian Medical College, Vellore, India
|Date of Web Publication||27-Apr-2018|
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Bright HR, Carey R. Low-Volume cigarette smoking is also harmful: Summary of study. Curr Med Issues 2018;16:18-9
Source: This is a summary of the study: Low cigarette consumption and risk of coronary heart disease and stroke: meta-analysis of 141 cohort studies in 55 study reports. BMJ. 2018 Jan 24;360.(1) Summary prepared by Mr. Heber Rew Bright, Lecturer, Department of Pharmacy Services, Christian Medical College, Vellore, India and Dr. Ronald Carey, Associate Professor, Department of Medicine, Christian Medical College, Vellore, India.
Clinical Question: Is it acceptable to smoke fewer number of cigarettes a day to reduce the risk of coronary heart disease, stroke, and other cigarette-related illnesses?
Authors' conclusions: There exists no safe level of smoking for coronary heart disease (CHD). Smokers only have to quit to significantly reduce the risk of CHD and stroke.
| Why This Study?|| |
Cigarette smoking is one of the largest preventable causes of premature deaths globally. A recently published meta-analysis by London-based researchers  concluded that smoking even one cigarette per day carries a risk of developing coronary heart disease (CHD) and stroke much greater than expected (around half of the people who smoke 20 cigarettes/day). The researchers went on to say that there exists no safe level of smoking for CHD. Smokers only have to quit to significantly reduce the risk of CHD and stroke.
| Methodology and Results|| |
The researchers reviewed 141 cohort studies that followed 5.6 million individuals from 21 countries published between 1946 and May 2015 that reported the association between cigarette consumption and CHD and stroke.
Smoking one cigarette a day is associated with a 48%–74% increase in the risk of CHD in men and a 57%–119% increase in CHD risk for women. The results also reflected a decreasing strength of association between CHD and smoking as people get older. However, the excess risk for smoking one cigarette per day expressed as a percentage compared to that of 20 cigarettes/day remained high throughout.
With respect to stroke, the risk remains proportionate to that of CHD. The relative risk for stroke among men who smoked one cigarette per day (1.25) is only slightly lower than as for those who smoked 20 cigarettes/day (1.64). These are again consistent with a slightly larger effect of smoking in women at the lowest smoking levels but more so at higher consumption, compared with men.
The meta-analysis included 5.6 million individuals for CHD and 7.3 million for stroke. It also included 110,000 new cases of CHD and 135,000 cases of stroke. Risks associated with one, five, and 20 cigarettes a day were modeled in each study for CHD and stroke.
| Discussion|| |
India has over 100 million adult smokers, the second highest number of smokers in the world after China. There are already about one million adult deaths per year from smoking. Although the prevalence of smoking declined modestly among men in India, the absolute number grew from 79 million in 1998 to 108 million in 2015. However, female smoking has not likely risen over these years. Further, smoking cessation remains uncommon – only about 5% of men aged 45–59 years were ex-smokers.
The high cardiovascular risk associated with very low cigarette use has major public health implications. Light smoking, occasional smoking, and smoking fewer cigarettes all carry substantial risk of cardiovascular disease. Only complete cessation is protective which should be emphasized by all prevention measures and policies.
More effective tobacco control policy needs to be implemented in India. Furthermore, intervention programs to raise the currently low levels of tobacco cessation are needed.
| Conclusion|| |
The findings of this study also underscore the risk for CHD and stroke with secondary/passive smoking which can be considered as another form of low-dose smoking. The results may also be generalized to other forms of tobacco use including bidis, which still remains the most common form of smoked tobacco in India. Smokeless tobacco use including khaini, gutkha, paan, and dry snuff is also very common in India. Women in India are more likely to use smokeless tobacco.
The concluding message is that tobacco use in any form, size, or shape carries a significant risk for CHD and stroke.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Hackshaw A, Morris JK, Boniface S, Tang JL, Milenković D. Low cigarette consumption and risk of coronary heart disease and stroke: Meta-analysis of 141 cohort studies in 55 study reports. BMJ 2018;360:j5855.
Mishra S, Joseph RA, Gupta PC, Pezzack B, Ram F, Sinha DN, et al.
Trends in bidi and cigarette smoking in India from 1998 to 2015, by age, gender and education. BMJ Glob Health 2016;1:e000005.