Smoking and Health

1. Smoking and Health Robert West University College London September 2011

2. Outline • What is happening to smoking prevalence in Britain? • Why do people smoke when it is so harmful? • What are the harms of smoking and benefits of stopping? • What are smokers doing about stopping? • What can be done by the NHS to help smokers to stop?

3. Smoking prevalence in Great Britain: trends Tax only ‘Smoking Kills’ • Smoking prevalence declined by 0.8% per year until 1993 then the decline stalled • The decline then resumed in 1998 following ‘Smoking Kills’: • 25% fewer smokers in 10 years • 50% fewer smokers aged 11-15 years GLS 2008 PHR 2009

4. Smoking prevalence in Great Britain: recent trends GLS 2008 ? PHR 2009

5. Smoking prevalence: Nov 2006 onwards Smoke-free www.smokinginengland.info

6. Cigarette smoking prevalence by age group

7. Mean price paid for 20 cigarettes N=10,920 smokers; includes hand-rolled; p<0.001 for increased cost per cigarette and decrease in cigarette consumption

8. Why people smoke Trying cigarettes Mainly social and personality factors Regular smoking Social factors and response to nicotine Not trying to stop Low health concerns, smoker identity, enjoying smoking, absence of triggers Failure of quit attempts Addiction, smoking triggers

9. The ‘Smoking Pipe’ Promoting cessation Reducing uptake 15 yr old smokers turning 16: 106K Trying to quit: 3.49M Reducing uptake Smokers Taking up smoking post 16: 165K Dying: 94K Relapsing: 3.06M Harm reduction Promoting cessation www.smokinginengland.info

10. Addiction to cigarettes • Cigarettes deliver nicotine rapidly to the brain via the pulmonary circulation in a form that is convenient and palatable • Nicotine delivered in this way is highly addictive • The primary mechanism is ‘operant learning’ • Smoking is rewarded (‘positive reinforcement’) • Abstinence is punished (‘negative reinforcement’)

11. Positive reinforcement • Nicotine binds to nicotinic acetylcholine receptors in the Ventral Tegmental Area

12. Positive reinforcement • This increases NDMA-initiated burst firing of the mesolimbic dopamine pathway

13. Positive reinforcement • This increases release of dopamine in the Nucleus Accumbens • Nicotine alsoaffects the operation of metabotropic glutamate receptors 5 (mGluR5) found in the nucleus accumbens and may play a role in modulating the post-synaptic response to both glutamate and dopamine

14. Positive reinforcement • The dopamine release ‘teaches’ the smoker to repeat the action of puffing on a cigarette just like feeding a dog teaches it to sit up and beg

15. Negative reinforcement • Prolonged exposure to nicotine results in neural adaptation • Nicotine is rapidly removed from the body by metabolism and excretion with a half life of about 120 minutes • Even short periods of abstinence lead to ‘withdrawal symptoms’ • Smoking a cigarette alleviates these symptoms • This ‘teaches’ the smoker to smoke when symptoms of this kind occur

16. Negative reinforcement Withdrawal discomfort, craving Puff on a cigarette Withdrawal relief More puffs

17. Nicotine withdrawal symptoms

18. The double ‘whammy’ • Smoking is rewarded and abstinence is punished • Both of these processes tap into ancient motivational systems that evolved millions of years before humankind • When a smoker ‘decides’ to try to stop, he or she is fighting these processes

19. Addiction to cigarettes I really want to stop smoking: it’s costing me money and it will probably kill me Just smoke

20. Health consequences of smoking • Lung cancer: the ‘escalator of death’ – smokers need to get off as young as possible • The risk never goes down in absolute terms

21. Health consequences of smoking • COPD: the only major disease category that is growing in the UK • Stopping smoking immediately normalises the decline in lung function

22. Health consequences of smoking • CHD risk starts to reduce immediately and the excess risk is halved after 12 months • This is probably because a large part of the risk is due to acute increase in MI risk from inhaling smoke particles, similar to effect of air pollution

23. Lesser known effects of smoking Other cancers: bladder, cervix, head and neck Disability: macular degeneration, deafness, back pain Appearance: wrinkles Reproduction: impotence, infertility, perinatal mortality Offspring: SIDS, learning difficulties, delinquency

24. Motivation to stop in recent years N=12856, p<0.001 for nonlinear change over time

25. Motivation to stop predicting quit attempts N=2088, p<0.001 for linear trend

26. Association between smoking motives and attempts to quit in the past year Final model from forward stepwise logistic regression of attempt to stop in past 12 months on to beliefs about smoking. Odds ratios less than 1 represent negative associations. N=3033

27. Association between motives to stop smoking and attempts to quit in the past year Final model from forward stepwise logistic regression of attempt to stop in past 12 months on to beliefs about smoking. Odds ratios less than 1 represent negative associations. N=5647

28. What determines success at stopping? • At all times after the designated quit point • the motivation not to smoke must exceed the motivation to smoke • when there is an opportunity to smoke • Motivation to smoke: • experienced as ‘desire’ (want or need) • affected by internal ‘drive’ state, external ‘cues’ and expectation of pleasure, relief of discomfort in the current situation or goals (e.g. weight loss) • Motivation not to smoke: • experienced as ‘restraint’ • affected by resolve, anticipated shame, guilt or disappointment

29. Key points on desire • Levels of desire change from moment to moment as a function of internal states and external cues • Internal factors leading to higher level of desire: • earlier in quit attempt • later in the day • when hungry or dysphoric • External factors leading to higher level of desire: • when opportunity is present • in situations normally accompanying smoking • when unoccupied • in presence of reminders of smoking • Abstinence violation may increase desire

30. Key points on restraint • Levels of restraint change from moment to moment as a function of internal states and external cues • Internal factors leading to higher level of restraint: • self-efficacy/confidence • self-labelling as non-smoker • commitment/resolve • External factors leading to higher level of restraint: • example of others • reminders of need for abstinence • social pressures to abstain • Abstinence violation may decrease restraint

31. The dynamics of abstinence Smoking Abstinent Motivation not to smoke Motivation to smoke Time Once the lines cross, given the opportunity, smoking occurs

32. Principles underpinning treatment • Treatment aims to: • reduce motivation to smoke (desire) • enhance motivation to remain abstinent (restraint) • It recognises that there it nothing qualitatively distinctive about this form of learned behaviour; it is subject to a moment-to-moment balance of motivational forces

33. Goals of treatment Smoking Abstinent Motivation not to smoke Motivation to smoke Time The treatment may have chronic or short-term effects on either or both curves

34. Clinical interventions are effective at improving success rates Compared with placebo when added to group or individual support Compared with brief advice or written materials Data from Cochrane reviews; statistically significant effects with combined sample size >1000 and no significant heterogeneity

35. Some treatments are better than others Data from Cochrane reviews; statistically significant effects with combined sample size >1000 and no significant heterogeneity

36. What are the NHS Stop Smoking Services? • 150 local services each serving an average population of 60,000 smokers • Providing a programme of behavioural support and medication to smokers wanting help with stopping • Free of charge (apart from small prescription charge in some cases) • Funded from general taxation, part of the National Health Service • Group and individual sessions held in GP practices, health centres, pharmacies or other local facilities • Stop smoking advisors are mainly nurses, psychologists and pharmacists

37. Large numbers of smokers treated Nearly 800,000 smokers treated

38. Only a minority of smokers get what they recognise as behavioural support 130,000 report having received behavioural sypport Smoking Toolkit Study: www.smokinginengland.info

39. Specialist Stop Smoking Services are effective Significantly better than no aid adjusting for confounding variables, p<0.001 Data from www.smokinginengland.info; based on smokers who tried to stop in the past year who report still not smoking at the survey adjusting for other predictors of success (age, dependence, time since quit attempt, social grade, recent prior quit attempts, abrupt vs gradual cessation): N=7,939

40. GP advice to stop smoking Percentage of smokers and recent ex-smokers for whom …; data from Smoking Toolkit Study, N=7611

41. Attempts to stop according to GP advice to stop smoking N=7611, p<0.001 for difference between offer of support/prescription and others

42. Resources • www.ncsct.ac.uk • www.treatobacco.net • www.rjwest.co.uk • www.smokinginengland.info