Causes and risk factors
Nicotine addiction is better understood now
The underlying cause of regular, daily smoking is nicotine addiction. Tobacco smoke contains nicotine, which creates a strong physical and psychological chemical dependence or addiction. Besides nicotine, tobacco smoke also contains thousands of other chemicals, such as tar, carbon monoxide, acetaldehyde and nitrosamines. The cigarette is a very efficient nicotine delivery system. When inhaling cigarette smoke, a smoker takes in 1 to 2 mg of nicotine per cigarette. Nicotine levels peak in the blood and reach the brain rapidly, triggering several reactions, such as increases in blood pressure, heart rate and respiration rate. In the brain, nicotine stimulates reward pathways that regulate feelings of pleasure.
Dependence is strongest when tobacco smoke is inhaled into the lungs and increases with the quantity and speed of nicotine absorption. An improved understanding of addiction and of nicotine as an addictive drug has been instrumental in developing medications and behavioural treatments for tobacco addiction (NIDA, 2006).
Sex, age, socio-economic status as determinants of smoking
The prevalence of smoking is higher among men than among women. Although more and more women are taking up smoking, this picture is not likely to reverse. Female smoking rates reached a plateau at lower levels than male rates in some countries, and have started decreasing in some countries. The Global Youth Tobacco Survey, however, showed that the difference in smoking rates between boys and girls is narrower than expected, especially in the Americas and in Europe. In the Americas, more girls smoke than boys, and there is only a small difference between the sexes in Europe, with 19.9% of boys smoking, and 15.7% of girls. The unexpected increase in cigarette consumption among girls will have important implications for the global burden of chronic diseases and should be considered in future mortality projections (Warren et al., 2006).
The prevalence of smoking is generally higher among young people than among the elderly. The Global Youth Tobacco Survey also revealed that Europe has the highest incidence of youth smoking in the world. Nearly 18% of Europeans aged 13 to 15 are smokers, more than twice the global average of 8.9% (Warren et al., 2006).
Socio-economic inequalities in smoking
The tobacco epidemic can be divided into four socio-economic related stages (Cavelaars et al., 2000). These are described in: detailsSocio-economic aspects of the tobacco epidemic.
In most countries smoking is more prevalent among the lower educated, whereby education can be viewed as an indicator for socio-economic status.
A general north-south pattern can be observed, with strong social gradients in northern European countries and weaker or reversed social gradients in southern European countries (Eurothine, 2007). Social gradients in smoking prevalence are stronger for younger men and women than for the older generations. These stronger social gradients of smoking prevalence are likely to translate into stronger gradients in smoking attributable morbidity and mortality in the future (Cavelaars et al., 2000).