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

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

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

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

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

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

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

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

Accuracy of self-reported smoking status by age in population surveys Never smokers Ex-smokers % smoking by cotinine (>14ng/ml) 16-24 7.3 20.2 25-34 1.5 9.6 35-44 1.6 6.3 45-54 0.8 4.2 55-64 0.5 4.0 65+ 1.1 3.0 All ages 2.0 4.9 Self-report: no smoking, no use of nicotine replacement products HSE 1998 & 2001 combined

How accurate are claims of quitting in population surveys? Reported time since quitting n % smoking by cotinine Mean cotinine (ng/ml) < 6 months 89 15.7 136 6-12 months 150 24.7 172 1-2 years 152 17.8 204 2-5 years 465 7.7 111 5-9 years 662 7.1 162 10-19 years 1316 3.8 183 20+ years 2073 1.5 135 All quitters 6407 4.9 160 HSE 1998 & 2001 combined

Nicotine intake and questionnaire indicators of dependence

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

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

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

Variation in nicotine intake by cigarette consumption

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

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

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

Product smoked and nicotine intake

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

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

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

Socio-economic variation in nicotine intake

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

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

Variation in nicotine intake across populations

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

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

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

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

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

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

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