Smoking

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Smoking tobacco is deleterious and addictive. The pharmalogically active ingredient is nicotine. Showing some of these deleterious effects got Richard Doll a knighthood but have still not convinced the vested interests, including those addicted, to do all possible to discourage smoking. It is a multi-billion dollar industry.

UK Warning on cigarette packet (2003)

Contents

Smoking History

Age started. Change in numbers. Quantity. Can be used to calculate total pack-years, where one pack year is the exposure equivalent to smoking 20 cigarettes a day for a year. This is rough and ready way of comparing exposure as not all patients smoke cigarette the same way.

12.5g or half an ounce of loose tobacco approximates to one pack.[1]

Not Starting

Clearly this requires a social approach. The change to Scottish law in 2005-6 and the lesser changes creeping slowly into English law in later years, making smoking in a variety of public spaces unlawful, should help.

Stopping

QuotationMarkLeft.png Stopping smoking is easy, I've done it dozens of times QuotationMarkRight.pngSamuel Clemens

Nicotine replacement (NRT) works, so does bupropion but not so cost effectively. Varenicline seems more clinically effective than NRT at a cost both in pounds and possibly more significant side-effects. Various approaches have been suggested and publicised, fundamentally, nothing works at the wrong time, and if you are fortunate enough to be consulted at the right time, the smallest of nudges may be of assistance in making the decision to quit. link to discussion of NICE guidance

Psychology
  • Understand the model of the process leading to a decision.
  • There is no magic psychological technique or tactic which will make people decide.
  • Although nicotine is the addictive component conditional addiction is likely. Thus issues with e-cigarettes include that they may not be as effective as nicotine replacement delivered by other means and might actually pre-dispose to smoking in the smoking naive who start their addictive behaviour with them.
Drugs

Nicotine, bupropion, varenicline.

Tobacco Control

A complex matter of public policy, tax, criminality and health. (see talk)

Problematically for those against it the evidence is sufficient to infer a causal relationship between the implementation of a smokefree law or policy and a reduction in coronary events among people younger than 65 years of age[2]

Conditions aggravated by/associated with Smoking

Mortality

Definitely causative of increased mortality as of 2014[2]:

  • Malignant neoplasms
    • Lip, oral cavity, pharynx (ICD10 C00–C14) - RR current smokers males 10.89, females 5.08
    • Oesophagus (ICD10 C15) - RR current smokers males 6.76, females 7.75
    • Stomach (ICD10 C16) - RR current smokers males 1.96, females 1.36
    • Pancreas (ICD10 C25) - RR current smokers males 2.31, females 2.25
    • Larynx (ICD10 C32) - RR current smokers males 14.60, females 13.02
    • Trachea, lung, bronchus (ICD10 C33–C34) - RR current smokers males 23.26, females 12.69
    • Cervix uteri (ICD10 C53) - RR current smokers 1.59
    • Kidney and renal pelvis (ICD10 C64–C65) - RR current smokers males 2.72, females 1.29
    • Urinary bladder (ICD10 C67) - RR current smokers males 3.27, females 2.22
    • Acute myeloid leukaemia (ICD10 C92.0) - RR current smokers males 1.86, females 1.13
  • Cardiovascular diseases
    • Coronary heart disease (ICD10 I20–I25)
      • Persons 35–64 years of age - RR current smokers males 2.80, females 3.08
      • Persons ≥65 years of age - RR current smokers males 1.51, females 1.60
  • Other heart disease (ICD10 I00–I09, I26–I28, I29–I51) - RR current smokers males 1.78, females 1.49
  • Cerebrovascular disease (ICD10 I60–I69)
    • Persons 35–64 years of age - RR current smokers males 3.27, females 4.00
    • Persons ≥65 years of age - RR current smokers males 1.63, females 1.49
  • Atherosclerosis (ICD10 I70) - RR current smokers males 2.44, females 1.83
    • Aortic aneurysm (ICD10 I71) - RR current smokers males 6.21, females 7.07
    • Other arterial disease (ICD I72–I78) - RR current smokers males 2.07, females 2.17
  • Respiratory diseases

Associations with increased mortality as of 2014[3]

  • Any infections
  • Breast cancer (women)
  • Prostate cancer (men)
  • Other rare cancers (RR 1.2)
  • Hypertensive heart disease
  • Essential and secondary hypertension
  • Other respiratory diseases
  • Ischaemic disorders of the intestines
  • Liver cirrhosis
  • Other digestive diseases
  • Renal failure

Morbidity

(note: some grouping duplication is inevitable and can be resolved by following the links. Some common usage group terms are also added for convenience. For example the popular term lung cancer refers to squamous cell carcinoma of the bronchus, small cell carcinoma of the bronchus, large cell carcinoma of the bronchus and the rarer adenocarcinioma of the lung, all of which are independently associated with increased risk in smokers) This list is in constant evolution and last update was 2014[2]

Conditions where evidence is suggestive but not definite

Conditions ameliorated by Smoking

Actual risks

These have been quite well defined for many conditions, particularly acute myocardial infarction (AMI). There is an effectively linear dose response curve up to 21 cigarettes smoked per day with the odds of developing AMI increased by 1.056 (95% CI 1.05-1.06) for every additional cigarette smoked. So at 10 cigarettes a day you double your odds of an AMI, at 20 you quadruple the odds. At 40 or more per day the odds ratio is 9.16 (95% CI 6.79-12.36)[5]. Mortality in diabetic smokers and non-smokers has been explored in detail as a function of body mass index. Once early deaths are eliminated we find that the J shaped curve in mortality as related to BMI is almost totally driven by low BMI smokers. Non smokers have a close to linear relationship between BMI and increased mortality[6]. In other words those diabetics with a low body mass index (BMI between 18.5 to 22.4) and who smoke are at much higher risk of mortality so reducing weight by smoking does not work.

Type of tobacco

Makes little difference:

INTERHEART risks of non-fatal acute myocardial infarction[5]
Type of Tobacco odds ratio (OR) 95% CI
Smoking Cigarettes 2.95 2.77-3.14
Filter Cigarettes 2.92 2.73-3.12
Non-Filter Cigarettes 2.35 1.96-2.82
Chewing Tobacco 2.23 1.41-3.52
Chewing Tobacco and smoking 4.09 2.98-5.61
Smoking Beedies (tobacco wrapped in temburini leaf) 2.89 2.11-3.96
Pipe or Cigar smoking 3.30 2.20-4.96
Use of Sheesha/hookah/water pipe 2.16 1.06-4.39

Change with risk with age

The relative risk of an acute myocardial infarction for a given amount of smoking is actually far greater the younger you are. This makes sense as the absolute risk of an acute myocardial infarction for reasons over which you have less control increases with age. So a former smoker aged less than 40 has an odds ratio of 2, but if still smoking an odds ratio of 4 if smoking less than 20 a day and an odds ratio of 7 if smoking more than 20 a day. This compares to a smoker aged more than 70 who has only an odds ratio of 2.5 if they are smoking 20 or more cigarettes a day.[5]

Age standardised mortality risk per 100,000 patient years in current smokers and never smokers illustrating how leaness or obesity compounds the risk[7]

Financial costs of smoking

According to research by the NHS Smoking Helpline,[8] the average 20-a-day smoker coughs up an additional £1,824 for cigarettes each year, and an additional £676 on other costs, bringing total spending on their habit to more than £2,500. Additional costs include:

  • Tackling burns, stains and odours associated with smoking, including dry cleaning bills, which adds a further £200 to the total spent by smokers.
  • Higher energy bills than non-smokers, with estimates suggesting that they pay about ten per cent more for energy due to costs associated with ventilating smoking rooms.
  • Health and life insurance: smokers can expect to pay more for health and life insurance, with one insurance company claiming that smokers' life insurance premiums are up to a third higher than those paid by non-smokers.

Change with risk with obesity

There is actually a J shaped curve for risk of death for a given body mass index with smoking grossly enhancing the absolute risk of death if you are too thin or too fat.[7]

Smoking in pregnancy

Not a good idea for the child to be as it lowers birth weight[9], is associated with premature birth and of dying of sudden infant death syndrome, reduces cognitive development[10] and is associated with many childhood medical problems such as diarrhoea, anorexia and meteorism[4]. The increased relative risk of these conditions is generally between 20% to 50% over non-smoking mothers but some effects are great enough to be detected in passive smoking exposure of non smoking mothers to be[11].

Legislation relating to smoking and tobacco control

In the UK, in England and the devolved administrations, smoking is banned, under the Health Act 2006, in workplaces and enclosed public places.

External links

References

  1. Wood DM, Mould MG, Ong SB, Baker EH. Pack year" smoking histories: what about patients who use loose tobacco? Tobacco control 2005;14(2):141-2. (Direct link – subscription may be required.)
  2. a b c The health consequences of smoking: 50 years of progress: a report of the Surgeon General. Atlanta: Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014
  3. Carter BD, Abnet CC, Feskanich D, Freedman ND, Hartge P, Lewis CE, Ockene JK, Prentice RL, Speizer FE, Thun MJ, Jacobs EJ. Smoking and mortality--beyond established causes. The New England journal of medicine. 2015 Feb 12; 372(7):631-40.(Link to article – subscription may be required.)
  4. a b Ludvigsson JF. Epidemiological study of constipation and other gastrointestinal symptoms in 8000 children. Acta paediatrica (Oslo, Norway : 1992). 2006 May; 95(5):573-80.(Link to article – subscription may be required.)
  5. a b c Teo KK, Ounpuu S, Hawken S, Pandey MR, Valentin V, Hunt D, et al. Tobacco use and risk of myocardial infarction in 52 countries in the INTERHEART study: a case-control study. Lancet. 2006;368:647-58. (Direct link – subscription may be required.)
  6. Tobias DK, Pan A, Jackson CL, O'Reilly EJ, Ding EL, Willett WC, Manson JE, Hu FB. Body-mass index and mortality among adults with incident type 2 diabetes. N Engl J Med. 2014 Jan 16;370(3):233-44. doi: 10.1056/NEJMoa1304501.
  7. a b Adams KF, Schatzkin A, Harris TB, Kipnis V, Mouw T, Ballard-Barbash R, Hollenbeck A, Leitzmann MF. Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old. N Engl J Med. 2006;355(8):763-78
  8. Reported by netdoctor.co.uk
  9. Ward C, Lewis S, Coleman T. Prevalence of maternal smoking and environmental tobacco smoke exposure during pregnancy and impact on birth weight: retrospective study using Millennium Cohort. BMC public health. 2007; 7:81.(Epub) (Link to article – subscription may be required.)
  10. Julvez J, Ribas-Fitó N, Torrent M, Forns M, Garcia-Esteban R, Sunyer J. Maternal smoking habits and cognitive development of children at age 4 years in a population-based birth cohort. International journal of epidemiology. 2007 Aug; 36(4):825-32.(Link to article – subscription may be required.)
  11. Leonardi-Bee J, Smyth A, Britton J, Coleman T. Environmental tobacco smoke and fetal health: systematic review and meta-analysis. Archives of disease in childhood. Fetal and neonatal edition. 2008 Sep; 93(5):F351-61.(Link to article – subscription may be required.)