Nicotine and smoking: insights from the Health Survey for England

1. Nicotine and smoking: insights from the Health Survey for England Martin Jarvis CRUK Health Behaviour Unit University College London

2. Why the HSE? • General Household Survey is official source for national prevalence and has excellent coverage of socio-economic factors associated with smoking. So why bother with HSE? • Crucial added ingredient is cotinine, a quantitative measure of recent smoke inhalation

3. The nicotine model: scope and caveats • Nicotine does not drive smoking behaviour in a simple way to the exclusion of other influences • Nicotine-seeking modulated by individual, family, social and societal influences • Understanding how nicotine intakes vary with these factors is the aim • Implications especially for • Product modification and harm reduction • Cessation treatments

4. Issues to consider…..… • Person • Reliability of self-report • Preferred dose • Consumption • Occasional smoking • Product • Population • Passive smoking

5. Cotinine as a measure of nicotine intake and dependence • Main metabolite of nicotine, with t ½ ~16-20 hours • Quantitative measure of nicotine intake • Spot sample may give reasonable indication of steady state – hence of usual daily intake • Conversion factor: saliva cotinine 100ng/ml = ~6.7mg nicotine per day. Individual variation in nicotine metabolism, but estimates should be reasonably accurate when averaged across groups • Cotinine is a good indicator of the extent of nicotine dependence

6. What has cotinine got to offer? • Objective check on prevalence and cessation • Objective characterisation of extent of recent nicotine use • Indicator of extent of nicotine dependence • Measuring dependence in relation to: • Smoking history • Occasional smoking • Socio-economic status • Product smoked

7. Health Survey for England • Representative sample nationally aged 16+ • Home interview + nurse visit to take biological measurements • Data collected on demographics, smoking history at interview, saliva cotinine (gas chromatography) at nurse visit • Sample with cotinine: • 1998 10,532 smokers 2,689 • 2001 9,451 smokers 2,195

8. Self-reported smoking habits and cotinine concentrations Reported nonsmokers- no passive exposure Reported nonsmokers- exposed to Passive smoking Self-reported smokers Health Survey for England 1998 & 2001 combined

9. Accuracy of self-reported smoking status by age in population surveys Self-report: no smoking, no use of nicotine replacement products HSE 1998 & 2001 combined

10. How accurate are claims of quitting in population surveys? HSE 1998 & 2001 combined

11. Nicotine intake and questionnaire indicators of dependence

12. Relation of nicotine intake to time to first cigarette in smokers • Fine-grained and continuous relationship. • Distinction between those who light up within 5 min and those who wait for 5-15 min HSE 1998 & 2001 combined

13. Relation of nicotine intake to time to first cigarette in smokers • Relationship of cotinine to time to first cigarette is largely independent of cigarette consumption HSE 1998 & 2001 combined

14. Cotinine by questionnaire measure of dependence • Dependence scale: • Time to first cigarette (1-6) • Perceived difficulty of abstaining for a whole day (0-3) • Cigarette consumption (0-3) HSE 1998 & 2001 combined

15. Variation in nicotine intake by cigarette consumption

16. Relation of cotinine to cigarette consumption in smokers • On average, cotinine increases linearly with consumption only up to 15-20 cigarettes a day HSE 1998 & 2001 combined

17. Wide variation in preferred nicotine intake between smokers • Although on average nicotine intake increases with cigarette consumption, at any level of consumption there is extremely wide variation in intake between smokers Health Survey for England 1998 & 2001

18. Cigarette consumption and nicotine intake: do light or occasional smokers take in less per cigarette? • On average, smokers take in about 1 mg nicotine per cigarette • Lighter smokers take in more per cigarette than do heavier • Little evidence for take-it-or–leave-it smokers. Based on equivalence 100 ng/ml saliva cotinine = 6.7mg nicotine per day (Benowitz) HSE 1998 & 2001 combined

19. Product smoked and nicotine intake

20. Low yield cigarettes and smoke intake • Nicotine intake is largely independent of machine-smoked nicotine delivery • Since tar and nicotine are highly correlated in smoke, tar exposure is unlikely to differ between smokers of low- and high-yield cigarettes HSE 1998 & 2001 combined

21. Low yield cigarettes and smoke intake • Nicotine yields have declined by 40% since 1980, but have smokers’ intakes reduced? . . . . British Regional Heart Study baseline 1978-80

22. Low yield cigarettes and smoke intake • On average, nicotine intakes in middle-aged men have shown no decline as tar/nicotine yields have declined by 40% • Consistent with complete compensation for nicotine • Indicates effective product modification will need to satisfy nicotine needs while reducing toxin exposure . . . . British Regional Heart Study baseline 1978-80, men aged 40-59 1990s data from HSE, age-matched to BRHS

23. Socio-economic variation in nicotine intake

24. Cotinine in smokers by socio-economic status • There is a marked gradient in nicotine intake by socio-economic status • Smokers in the most deprived category take in on average about one-third more nicotine HSE 1998 & 2001 combined

25. Cotinine and dependence in smokers • The socio-economic gradient in nicotine intake among smokers is independent of the product smoked – seen both in smokers of manufactured cigarettes and own-rollers HSE 1998 & 2001 combined

26. Variation in nicotine intake across populations

27. National differences in nicotine dependence among smokers • At any level of socio-economic deprivation, Scottish smokers have higher nicotine intakes than English smokers Scottish Health Survey 1995, 1998 Health Survey for England 1996, 1998

28. Passive smoking: effects of partner smoking • Dose-response relationship between partner’s smoking and cotinine in nonsmoking adults • On average, dose is about 0.7% of active smokers

29. National differences in nicotine dependence among smokers • At any level of socio-economic deprivation, Scottish smokers have higher nicotine intakes than English smokers Scottish Health Survey 1995, 1998 Health Survey for England 1996, 1998

30. Passive smoking: effects on children • Similar dose-response in children with smoking parents • Exposure in children is higher than in adults with smoking partner

31. Passive smoking and deprivation • In both adults and children, extent of exposure varies by socio-economic status

32. 10 reasons why I love the HSE • Large and representative sample • Household sampling frame • Excellent coverage of demographics • Smoking module as in GHS • Brand choice question • Time to first cigarette question • Cotinine – quantitative measure of smoke intake • Time series • Data can be combined across years • Comparison with SHS possible

33. Conclusions • Application of cotinine in smoking studies gives the opportunity for new insights into the nature and determinants of nicotine dependence • Cross-sectional studies can yield much information, but longitudinal studies are also needed to understand smoking careers • Lack of cotinine-based surveys in many countries hampers understanding • Better understanding of the contours of nicotine dependence important for developing more effective cessation treatments and for harm reduction • Policies that ignore or misunderstand the dynamics of nicotine seeking are highly likely to fail