Just one cigarette a day seriously elevates cardiovascular riskBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k167 (Published 24 January 2018) Cite this as: BMJ 2018;360:k167
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There are profound implications for preventative medicine from the fact that just 1 cigarette a day, like passive smoking and current levels of air pollution, has a third to half the additional CHD risk of smoking 20 a day.
Only 15.8% of UK adults smoke, so the excess population-weighted risk of active smoking is less than 16% of that of the average smoker. Passive smoking has an even lower population-weighted excess risk, thanks to comprehensive smoke-free laws for public places resulting in large (~15%) drops in hospital admissions for cardiac, cerebrovascular, and lung disease.
That leaves air pollution, which is much deadlier than previously thought. In Launceston, Tasmania, wintertime deaths from respiratory disease fell by 28% and cardiovascular disease by 20% when woodsmoke pollution was reduced by 17 ug/m3 PM2.5 in winter. Year round, for men, the reductions were 23% (respiratory) and 18% (cardiovascular).
In Canada, deaths from ischemic heart disease increased by 30% when annual PM2.5 exposure increased by just 10 ug/m3. The increase in hospital admissions for heart attacks in another Canadian study was greatest when the particles came from winter wood heating. On such days, a 10 ug/m3 increase 3-day mean PM2.5 increased hospital admissions for heart attacks by 38% in those aged 65+. In Hong Kong, a 10 ug/m3 increase annual PM2.5 exposure increased the risk of cancer by 22%, including a 42% increase for upper digestive tract cancers and 80% for breast caners in women.
Population exposure of 10 ug/m3 PM2.5 above background could therefore cause twice the health damage of current UK smoking levels. The damage from London’s average of 13.7 ug/m3 PM2.5 above background is expected to be even worse. London had extraordinary levels of health-hazardous pollution - 3-day mean PM2.5 of 78 ug/m3 in Kensington and 74 ug/m3 at the Sir John Cass School- on 22-24 January 2017, when about half the pollution was attributed to domestic wood burning.
Many people do not realize that the UK’s largest single source of PM2.5 - 37,200 tonnes - is domestic wood burning, representing 2.7 times the 13,900 tonnes emitted by road transport. An eco-labelled wood stove is allowed to pollute as much as 25 ten-year-old diesel trucks. When measured under ideal conditions (good air intake and small pieces of dry wood), real-life emissions of an eco-labelled wood stove were 600 times worse than a small diesel truck. Despite this, Defra’s consultation on domestic burning (open until 27/2/2018) “is not seeking to prevent” the use or installation of new stoves, simply “encourage consumers to switch to cleaner wood burning”.
Such strategies have not worked in other countries. Despite extremely strict regulations, and substantial public education on how to burn cleanly, real-life emissions of 5 stoves in Christchurch, NZ, averaged 9.7 g/kg, 12 times worse than the lab test results averaging 0.82 g/kg.
Despite the mild climate in Sydney, Australia, the average new wood stove emits more PM2.5 per year than 1,000 petrol cars. Only 5% of households use wood as the main form of heating, yet chemical fingerprinting of particulate pollution showed that 25% of Sydney’s premature deaths from air pollution were from domestic wood heating. Estimated health costs amount to thousands of dollars per stove per year.
A New Scientist review in 2017 concluded that “log-burning stoves are harming our health and speeding up global warming”. As well as strokes and heart attacks, the mixture of PM2.5 and toxic chemicals emitted by wood stoves increases the risk of lung diseases, cancers, cot deaths, asthma, Alzheimer's, genetic damage in babies and reduced IQ, anxiety and attention deficit when children start school.
Many effects appear to be substantial. Increased exposure of just 1 ug/m3 PM2.5 increased the risk of dementia by 8%, Alzheimer's by 15% and the risk of Parkinson’s diseases by 8%. Increased exposure of 3.5 ug/m3 reduced the volume of white matter in the brain by 6.2 cubic centimetres. Exposure to PM2.5 pollution above the US EPA standard of 12 ug/m3 nearly doubles the risk of cognitive decline and all-cause dementia for most people and quadrupled the risk for those with 2 copies of the APOE gene.
Non-polluting heating is readily available. An efficient 5 kW air source heat pump can cost less to buy and install than a 5 kW stove and needs only about 1.1 kWh of electricity (costing about 13 p) to provide 5 kW heat. By contrast, although the nominal emissions limit for a 5 kW stove approved for use in smokeless zones is 6.7 g/hr, real-life emissions are expected to exceed 10 g/hr implying health costs of £1.58/hr in inner and £0.90/hr outer London, many times greater than the cost of environmentally-friendly heating.
A study of airborne particles in UK cities estimated that wood burning was between 23% and 31% of urban derived PM2.5 in London and Birmingham. Woodsmoke pollution was higher at weekends and in the evenings, but poorly correlated with daily temperature, suggesting that it “is in large part decorative and not being used for primary heating.”
With PM.25 pollution causing more damage to population health than cigarettes, with domestic wood burning the largest single-source of UK PM2.5 emissions and ready availability of affordable, non-polluting, environmentally-friendly alternatives, sensible policies are needed to protect public health.
Can there be any justification for allowing the installation of new stoves with estimated annual health costs (for an average 563 hours a year) of £889 in inner and £510 in outer London? At the very least “polluter-pays” taxes equal to the estimated health costs should be levied.
The health damage from misguided diesel policies continues. Policies on wood stoves will be even more misguided, unless many health professionals participate in the consultation ( before Feb 28) and argue for effective regulations to protect public health.
1. Johnson, K.C., Just one cigarette a day seriously elevates cardiovascular risk, 2018, British Medical Journal Publishing Group.
2. Guardian. Smoking rate in UK falls to second-lowest in Europe. Available at: www.theguardian.com/society/2017/jun/15/smoking-rate-in-uk-falls-to-seco.... 2017.
3. Robinson, D.L., What makes a Successful Woodsmoke-Reduction Program? Air Quality and Climate Change, 2016. 50(3-4).
4. UTAS. Reduction in air pollution from wood heaters associated with reduced risk of death. University of Tasmania media release. . 2013; Available from: http://www.media.utas.edu.au/general-news/all-news/reduction-in-air-poll....
5. Crouse, D.L., et al., Risk of Non-accidental and Cardiovascular Mortality in Relation to Long-term Exposure to Low Concentrations of Fine Particulate Matter: A Canadian National-level Cohort Study. Environ Health Perspect, 2012.
6. Weichenthal, S., et al., Biomass Burning as a Source of Ambient Fine Particulate Air Pollution and Acute Myocardial Infarction. Epidemiology, 2017. 28(3): p. 329-337.
7. Wong, C.M., et al., Cancer Mortality Risks from Long-term Exposure to Ambient Fine Particle. Cancer Epidemiology Biomarkers & Prevention, 2016.
8. Walton, H., et al., Understanding the Health Impacts of Air Pollution in London. Available at: www.london.gov.uk/sites/default/files/HIAinLondon_KingsReport_14072015_f..., 2015.
9. Page, M.L., Wood-burners: London air pollution is just tip of the iceberg. Available at: www.newscientist.com/article/2119595-wood-burners-london-air-pollution-i.... New Scientist, 2017.
10. NAEI. UK emissions data selector. Available at http://naei.beis.gov.uk/data/data-selector?view=pms (select domestic combustion). 2018.
11. Kåre Press-Kristensen, Pollution from residential burning, Danish experience in an international perspective. Available at: http://shop.ecocouncil.dk/varedetaljer.asp?shopid=851152&funique=287&kat..., 2016, Danish Ecological Council.
12. Defra. Call for Evidence - Domestic Burning of House Coal, Smokeless Coal, Manufactured Solid Fuel and Wet Wood - consult.defra.gov.uk/airquality/domestic-burning-of-wood-and-coal/. 2018.
13. AAQG. New Woodheaters Pollute - woodsmoke.3sc.net/new-woodheaters-pollute. 2016.
14. AAQG. Sydney - woodsmoke.3sc.net/syd. 2016.
15. AAQG. Health experts advise that current wood heater models are too polluting to be allowed. Australian Air Quality Group. Available at: http://woodsmoke.3sc.net/health. 2015.
16. Air Quality Expert Group, The Potential Air Quality Impacts from Biomass Combustion. Available at: http://uk-air.defra.gov.uk/assets/documents/reports/cat11/1708081027_170..., 2017.
17. Font, A. and G. Fuller, Airborne particles from wood burning in UK cities. Available at: uk-air.defra.gov.uk/library/reports.php?report_id=953, 2017.
Competing interests: No competing interests
KC Johnson comments on "Just one cigarette a day increases cardiovascular risk" warning that, by the same token, use of e-cigarettes may not reduce the risk of CHD and stroke. Our research at the University of Surrey suggests that nicotine addiction is only part of the problem for smokers trying to quit.
We identified 10 other de-motivators: optimism bias, confirmation bias, attentional bias, post traumatic stress disorder (PTSD), anxieties about weight gain, side effects of smoking cessation pharmacotherapy, fatalism, peer pressure, lack of family cohesion and inadequacy of a risk score used in our research. We were surprised to find that PTSD was a significant factor in failure of smoking cessation [1,2,3] and there is evidence from Vitnam war veterans that nicotine inhibits symptoms of PTSD . We estimated that the incidence of overt PTSD is 3 times commoner in smokers than in non-smokers and another researcher has demonstrated that 6.7% of smokers suffer from overt PTSD and 73% have some features of PTSD . This may indicate that PTSD caused by unreported domestic abuse and sexual abuse may also explain why many smokers who would like to quit find it impossible.
More research is needed in this area to see if modern treatment of PTSD can help smokers to quit. Also the rapid nicotine bolus experienced by smokers but not by nicotine replacement therapy seems to be needed to block PTSD symptoms. E-cigarettes may be the only "bridge" between smoking and smoking cessation that delivers a similar nicotine bolus and research on this approach to smoking cessation is urgently needed despite the warnings of KC Johnson and others.
1. Nichols JAA. How Effective is Fear of Lung Cancer as a Smoking Cessation Motivator. In "Prevention, diagnosis and treatment of lung cancer", Ed Marta Adonis. Published by InTec, Croatia.
2. Mathew AR, Cook JW, Japuntich SJ, Leventhal AM. Post‐traumatic stress disorder symptoms, underlying affective vulnerabilities, and smoking for affect regulation. The American Journal on Addictions. 2015;24:39–46.
3. Beckham JC, Calhoun PS, Dennis MF, Wilson SM, Dedert EA. Predictors of lapse in first week of smoking abstinence in PTSD and Non‐PTSD Smokers. Nicotine and Tobacco Research. 2012;15:1122–1129.
4. Froeliger B, Beckham JC, Dennis MF, Kozink RV, McClernon FJ. Effects of nicotine on emotional reactivity in PTSD and non‐PTSD smokers: results of a pilot fMRI Study. Advances in Pharmacological Sciences. 2012:6 (Article ID 265724).
Competing interests: No competing interests
This is a thought provoking article. The paper categorically states that there should be total cessation of smoking. The myth of smoking few or large number of cigarettes has a different degree of vascular risk and smoking one cigarette per day has total freedom from the risk for vasculopathies should be removed from the minds of smoking population.
As throughout the world, the population is predisposed for stroke and cardiovascular disorders. These clinical disorders are becoming significant public health problem throughout the globe. One of the modifiable risk factors is control of smoking.
Smoking has multitude of adverse effects on vasculature. Arterial stiffness, increased thrombogenesis, abdominal artery aneurysm, carotid intimal media thickness and compounding other risk factors for vascular disorders.
Health authorities should pick up this challenge to educate the public at large about the hazards of smoking in a more effective manner. The government should make tough legislations to curtail the production of cigarettes and other related nicotinic products.
Competing interests: No competing interests
Re: Just one cigarette a day seriously elevates cardiovascular risk ;The implication for tobacco control is very clear: that reduced smoking will reduce one of the leading cause of adult death in India. Tobacco prevention in India is beginning to be addre
Today around one billion adults worldwide smoke cigarette or Bidi( (small, locally manufactured smoked tobacco) , even with high prevalence in developing countries, where 49% of men and 11% of women use tobacco. In the Health Survey for England (2013 and 2014), 26% of current smokers reported that they wanted to cut consumption down but were not trying to stop, and 40-41% said that they smoked less than in the previous year. The percentage of smokers who consume one to five cigarettes per day has steadily risen (from 18.2% to 23.6% between 2009 and 2014), with a similar pattern in the US, where the proportion of smokers who consume less than 10 cigarettes per day increased from 16% to 27% between 2005 and 2014 India has today over 120 million adult smokers, the second highest number of smokers in the world after China. There are already about 1.2 million adult deaths per year from cigarette /bidi smoking. The age-standardized prevalence of smoking though declined a little among men aged 15–78 years, but the absolute number of male smokers at these ages grew from 79 million in 1998 to 118 million in 2015. This may be due to population growth offsetting modest declines in prevalence. In Rural and Urban India Cigarettes are now displacing bidi , especially among younger men and among illiterate men. This change might further increase the numbers of smoker: non smoker relative risks of disease. Smoking cessation still remains uncommon—only about 5% of men aged 45–59 years are ex-smokers. India has about 3 current male smokers for every quitter at these ages. Female smoking at ages 15–69 years has likely also risen. According to the latest data on cigarette consumption given by the health ministry in Parliament, the consumption in 2014-15 was 93.2 billion sticks — 10 billion less than in 2012-13. The production of cigarettes too fell from 117 billion to 105.3 billion sticks in the same period. Even this author himself is a smoker for bidi and cigarette for 1-3 cigarettes per day /daily from 2001 to till date of 2018 and though he was a cigarette smoker( approx -20 ciggarate a day/daily since his college life as medicos student since 1974-2000) as it is /was easily available at every corners of road .
Cardiovascular diseases, especially coronary heart disease (CHD), are however epidemic in India . The Registrar General of India reported that CHD led to 17% of total deaths and 26% of adult deaths in 2001-2003, which increased to 23% of total and 32% of adult deaths in 2010-2013. The World Health Organization (WHO) and Global Burden of Disease Study also have highlighted increasing trends in years of life lost (YLLs) and disability-adjusted life years (DALYs) from CHD in India. In India, studies have reported increasing CHD prevalence over the last 60 years, from 1% to 9%-10% in urban populations and <1% to 4%-6% in rural populations. Using more stringent criteria (clinical ± Q waves), the prevalence varies from 1%-2% in rural populations and 2%-4% in urban populations. This may be a more realistic prevalence of CHD in India. Case-control studies have reported that important risk factors for CHD in India are in chronological orders dyslipidemias, smoking, diabetes, hypertension, abdominal obesity, psychosocial stress, unhealthy diet, physical inactivity and obesity. Ischemic heart disease and stroke are the predominant causes and are responsible for >80% of CVD deaths. Ischemic heart disease (IHD) and stroke constitute the majority of CVD mortality in India (83%), with IHD being predominant . The ratio of IHD to stroke mortality in India is significantly higher than the global average, and is comparable to that of Western industrialized countries. Together, IHD and stroke are responsible for more than one-fifth (21.1%) of all deaths and one-tenth of the years of life lost in India. In India, the age-standardized annual stroke incidence rate is 154 per 100000 per year(14%), smoking prevalence is higher among men (24%) than among women (3%), and smoking among individuals with less-than-primary education is higher for both sexes (37% and 4% for men and women, respectively). It is alarming that tobacco use is increasing rapidly among young individuals (20–35 years) in India, with a steeper rate of increase among those with lower education.Evidence also suggests that experimentation with tobacco starts relatively early among children in India.
A recent Cochrane review discussed the evidence for ways of helping smokers who wish to reduce their consumption. This meta-analysis by Allan Hackshaw et al is however based on 141 prospective cohort studies (involved approximately 12.94 million people and they showed that men who smoked one cigarette per day had 46% of the excess risk of heart disease and 41% of the excess risk of stroke when associated with smoking 20 cigarettes per day (1). Importantly, this study concluded: "No safe level of smoking exists for cardiovascular disease(CHD). Smokers should quit instead of cutting down, using appropriate cessation aids if needed by E cigarette as per Hackshaw et al , to significantly reduce their risk of these two common major disorders But authors experience is that e-cigarette does not help much to reduce the cigarette smoking , not available every where and costs too much . One E ciggerate costs in Kolkata market around 700 INR ie US $ 12 which is not affordable even by upper class society Smoking is considered as major risk factor for sudden coronary spasm but not in otherwise normal coronary artery but in coronary artery with calcified atherosclerotic plaques and at times may precipitate an acute cardiovascular event in susceptible individuals with calcified atherosclerotic plaques. Like intracoronary ergonovine (a potent coronary vasoconstrictor, used popularly in the cath. lab. to induce coronary artery spasm as and when needed), smoking even one cigarette may induce significant coronary artery spasm, at times precipitating an acute coronary event, notably in a dose-independent fashion. Not only smoke (active and passive) but time of the day of smoking is equally relevant. More harm during the early hours of the morning (maybe related to circadian variation in neurohormonal axis), as heavily addicted persons often light cigarettes upon waking What was so far our knowledge was one or five cigarettes per day reflect typical levels of low tobacco consumption and was less risk factors for AMI . Below the age 45, smokers of 25 or more cigarettes per day had a 33 times higher risk than non-smokers, compared to 7.5 at in the age group 45-54, 4.4 between the ages 55-64 and 2.5 at the age of 65 or over Relative risks for smoking more than 10 cigarettes or 10 bidis daily for 10 years or more is 9.1 (95% CI 4.7 to 17.7) and 8.1 (95% CI 4.3 to 15.3), respectively. It is estimated that smoking may cause 53% (95% CI 47% to 64%) of AMIs among urban males in India than zero smokers or never smokers . How ever Hackshaw et al did not included the reference group of never smokers in their study was indeed to be designed to compare the risks of 1 cigarette a day with zero consumption, then perhaps Hackshaw et al could be kind enough to expand on their logic. The onset of coronary artery disease including acute coronary syndrome is strongly involved in vascular spasm, platelet aggregation, which occur in the vascular endothelium. That is, a decrease in vascular endothelial function greatly affects the onset of acute coronary syndrome. There is a flow-mediated dilation of the brachial artery (FMD) as an index of vascular endothelial function. Complete smoking cessation improves vascular endothelial function assessed by FMD. Along with that, the oxidative stress marker also improves. But if they smoke again, the vascular endothelial function returns or gets even worse.
Smoking carries a huge economic cost with every one , for the this has been estimated to be $300 billion per year . This corresponds to about $300,000 per smoker during his/her lifetime.
1) Allan Hackshaw, Joan K Morris, Sadie Boniface , in-Ling Tang, ,Dušan Milenković Low cigarette consumption and risk of coronary heart disease and stroke: meta-analysis of 141 cohort studies in 55 study reports BMJ 2018; 360 doi: https://doi.org/10.1136/bmj.j5855 (Published 24 January 2018)Cite this as: BMJ 2018;360:j5855
Competing interests: No competing interests