• Overview
• Definition
• Incidence, prevalence and trends
• Risk factors
• Health consequences
• Costs
• Contributors

Definition

Humans ignite tobacco and inhale the smoke in various ways (cigarettes, cigars, pipes, bidis), chew it (spit tobacco) or retain it in their mouth (snus), or take it intranasally. New tobacco inhalation devices are being developed that might reduce the harm from inhaling smoke by heating it. However, cigarette smoking is by far the most common method of consumption in the UK. It is also the most harmful method. The term smoker in this section will refer to someone who smokes cigarettes.

Adult smokers

The question used to determine smoking prevalence is “Do you smoke cigarettes at all nowadays?”. This is likely to reveal a higher prevalence than asking “Are you a smoker?”.

About 2–3% of smokers do not smoke every day. ¹ The assumption is that such people are less dependent or addicted, although the role of addiction in non-daily smoking is controversial. ² Analogous questions are used to define cigar and pipe smoking and chewing tobacco.

Exsmokers

In national statistics, exsmoker is self defined. In the General Household Survey people are asked “Have you ever smoked cigarettes?” People who answer “yes” and then declare they are not smoking nowadays are assumed to be exsmokers. Improvements in public health are generated only by people who stop smoking and stay stopped for good.

Studies show that people who have stopped smoking can relapse many years after they give up. ³ This implies that we should define someone as an exsmoker only after they have died, which is not a useful definition. A practical definition of abstinence is the Russell standard, which states that six months of smoking no or almost no cigarettes is termed sustained abstinence, and implies the new behaviour is becoming entrenched. ⁴ Around half of people who do not smoke a cigarette for six months will never smoke again. This is based on combining the results of a few studies that have followed people for a long time. ^{5 6}

Adolescent smokers

The prevalence of smoking among people aged 11–15 years is measured annually. By convention the prevalence of smoking among adolescents is based on those smoking at least one cigarette per week.

Nicotine addiction

The main reason why people smoke is that they become addicted to nicotine early in their experimentation with smoking, and stopping becomes no longer a matter of choice. ⁷ Nicotine addiction is defined in classification of diseases such as the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV and the ICD 10. Using these criteria a minority of smokers fulfil the definition of nicotine addiction, but the criteria are disputed. ⁸

Most smokers fail in their attempts to stop. The consensus is that most smoking is maintained by addiction and that it is generally the degree of dependence that varies from smoker to smoker rather than whether dependence is present. ⁸