Literature review
Parental
Several studies have shown that parental smoking status does not only affect children's health through exposure to nicotine , but is also related to children's smoking onset . This suggests that young people who grow up in a smoking family environment are more likely to take up smoking themselves. Concerning the impact that parents have due to their own smoking behavior, the social learning theory of Bandura provides insight into the underlying mechanisms. According to social learning theory, many behaviors, such as smoking, are learned by observation. Individuals, such as parents, siblings, friends, and teachers, who share the same environment of the adolescent, influence the adolescents' behavior by exemplifying and by consciously or unconsciously reinforcing certain behaviors. Whether the adolescent will adapt these behaviors depends largely on actual and anticipated consequences. Thus, adolescents are more likely to smoke if they anticipate that smoking will result in generally positive outcomes, for example, watching their parents smoke at a party, thus associating smoking with pleasure and intimacy. If, on the other hand, the smoking behavior of role models is associated with negative outcomes, such as illness or stress, adolescents will be more inclined to refrain from smoking. In sum, if an adolescent anticipates that imitating the smoking habits of his or her parents will not have negative consequences, he or she will be more inclined to smoke.
Great majority of smokers starts the habit before 20 years of age (Young et al., 1989). There are many reasons for smoking, such as alleviation of stress, life problems, peer pressure, social acceptance issues, family history (parental modelling of smoking behaviour),
lower educational attainment, and lower economic status. Young smokers desire to appear mature, selfconfident and independent and to attain a high personality profile (Kegler et al., 1999). On the other hand, religion, sensory issues such as bad taste or smell, negative health consequences, impaired physical performance, negative physiological response, and issues related to family are considered as some of the reasons for not smoking (Felimban & Jarallah, 1994; Kegler et al., 1999). Attitudes and beliefs towards smoking predict intentions and starting of smoking (Brownson et al., 1992). Attitudes towards smoking serve as a deterrent to initiating smoking and as a stimulus to quitting (Chassin et al., 1984; Hansen et al., 1985). Great majority of pupils (smokers and non-smokers alike) recognise that smoking is harmful to the health (Smith, 1991). Contrarily, pupils who tried cigarettes had more adverse attitudes and beliefs about the effects of smoking compared to non-smokers (Greenlund et al., 1997). Smokers are responsible for their own health, yet most are still unaware of the grave dangers of smoking or of ways they could avoid them (Royal College of Physicians, 1983). Hill and Gray (1989) found most smokers did not believe that smoking caused illness and most of them thought that only those who smoke heavily (by which they meant those who smoke more cigarettes than they do themselves) are likely to get serious illnesses caused by smoking. In fact about onethird of all premature deaths caused by smoking occur in smokers who smoke less than 20 cigarettes per day (Royal College of Physicians, 1983).
Most smokers understood smoking as a strategy to cope with the social anxieties rather than as deviant or illegal behaviour (Leventhal et al., 1991). Use of cognitive coping and problem solving methods has been shown to be a deterrent to initiating smoking (Lotecka and MacWhinney, 1983) and to be maintaining abstinence among adults (Supnick & Colletti, 1984; Wewers,1988).
Peers
Smoking is still a significant problem affecting adolescents in the United States. The CDC reported in 2004 that 8.11% of middle school students and 22.3% of high school students had smoked cigarettes at least once in the past 30 days (Centers for Disease Control and Prevention, 2002). People who initiate smoking earlier in life smoke more throughout their lifetime and have a harder time quitting than people who initiate smoking later (Chassin, Presson, Pitts, & Sherman, 2000). One of the most important correlates of adolescent smoking is the smoking status of the adolescent's friends. Over ninety percent of middle school students who smoke also have a smoking friend (Centers for Disease Control and Prevention, 2001). An adolescent's risk for smoking increases if one friend smokes(Charlton & Blair, 1989; Dappen, Schwartz, & O'Donnell, 1996; Elder et al., 1996; Headen, Bauman, Deane, & Koch, 1991); this risk is higher if more than one friend smokes (Donato, Monarca, Chiesa,
Feretti, & Nardi, 1994). Several review studies have indicated that peer influence to smoking is a significant, and perhaps the most important, predictor of adolescent smoking (Conrad, Flay, & Hill, 1992; Kobus, 2003; Leventhal & Cleary, 1980; McAlister, Perry, & Maccoby, 1979; Sussman, Dent, Burton, Stacy, & Flay, 1995; Tyas & Pederson, 1998).
These studies indicate that there is homophily, or similarity, of adolescents to their friends in terms of smoking status. Homophily can be attributed to one of at least two factors - either the adolescent is
influenced to smoke by his friends in order to be more like them (peer influence, also referred to as peer pressure), or he is selecting friends based on their smoking status (peer selection; Ennett & Bauman,
1994).1 Research indicates that both peer influence and peer selection of smoking friends (i.e., smoking adolescents choosing smoking peers as friends) are needed to describe the relationship between adolescent smoking and peer smoking (Engels, Knibbe, Drop, & de Haan, 1997; Ennett & Bauman, 1994). If peer selection plays a significant role in adolescent smoking, then this may have implications for the planning and implementation of tobacco prevention programs, which currently do not take this influence into account.
The extent to which influence and selection play roles in adolescent smoking has not been well established. Peer influence is measured more often than peer selection, and without a longitudinal study
design it is impossible to determine which if any of these mechanisms are affecting adolescent smoking dynamics. Some researchers believe that peer influence is overestimated and selection is underestimated (Urberg, Degirmencioglu, & Pilgrim, 1997). However, studies that have measured both peer influence and peer selection effects have found that both factors influence adolescent smoking (Engels et al., 1997; Ennett & Bauman, 1994; Fisher & Bauman, 1988).
