The present study aimed to examine the factors predicting waterpipe smoking in adolescents in Birjand using the PWM. The results showed that 17.4% of the high school adolescents in Birjand had a history of waterpipe smoking. Similar to our study, Karimi et al. observed that the prevalence of waterpipe smoking was 17.3% among male adolescents aged between 15 and 19 years in Zarandieh, Iran (
11). In addition, Reveles et al. asserted that waterpipe smoking in Brazilian adolescents amounted to 19.7% (
12). Minaker et al. stated that 22.4% of high school students (grades 9 to 12) smoke waterpipe (
13). Apparently, the easy and plentiful access to various forms of waterpipe, as well as the absence of strict rules on tobacco products sales, is a major cause of its increased consumption in recent years (
14,
15). Due to the growing prevalence of waterpipe smoking among adolescent students, in order to control the use of tobacco products, the adolescents should be the primary target of preventive and educational interventions aiming at cutting tobacco consumption of any type. As a suitable environment, schools can be influential in prevention from waterpipe smoking by providing the students with influential and informative healthcare messages. The informative messages should highlight the long-term negative consequences of waterpipe smoking in health, as adolescents may be less vulnerable to the health risks associated with the use of different forms of tobacco products (
16).
The results of the present study revealed that all the three constructs of attitude, subjective norms and behavioral willingness had a direct relationship with behavioral intention, and could predict 49% of the change in waterpipe smoking intention; this was consistent with the results of the study by Abedini et al. in high school students in Bandar Abbas, southern Iran (
10). From these three constructs, the subjective norms construct was a more effective predictor of waterpipe smoking intentions, and this was in line with the results obtained by Hukkelberg et al. in their study on tobacco consumption in Norwegian adolescents. They argued that the intention of an adolescent for tobacco consumption is not the result of conscious thinking about tobacco smoking but primarily evoked by other people like parents or friends (
17). Jamil et al. observed a positive correlation between having a family member with a history of waterpipe smoking and the individual’s waterpipe smoking and suggested that social norms and family customs have an important role in starting and continuing waterpipe smoking among young people (
18). Therefore, interventions for preventing from waterpipe smoking at the interpersonal level may involve in encouraging the adolescents toward appropriate recreation through peer group networks, as well as empowering the family members to orient their adolescents toward promoting healthy behaviors by fostering healthy norms in the family.
The findings of this study showed that the constructs of prototype, subjective norms, and attitude had a positive correlation with behavioral willingness and explained 54% of the variance in behavioral willingness for waterpipe smoking and that the attitude was the most important behavioral willingness determinant. Barati et al. analyzed the social reaction path in the PWM and suggested that the positive attitude, subjective norms, and prototypes of the participants about cigarette smokers were associated with the willingness for tobacco consumption; these three constructs could explain 31% of the changes in behavioral willingness; and the behavioral subjective norms were the most important predictor of behavioral willingness (
19). Moreover, Karimi et al. stated that attitude can be a significant predictor of waterpipe smoking among adolescents (
11). Positive attitudes toward waterpipe smoking, such as believing that it has lower risks than cigarettes, increase the adolescents’ willingness to waterpipe smoking. This attitude can also be due to the good fragrance and pleasant taste of waterpipe, which disposes the adolescent’s willingness toward considering waterpipe smoking as an attractive leisure for socializing with friends (
20). In the present study, the adolescents’ prototypes of waterpipe smokers, although being a poor predictor of behavioral willingness, could predict 0.07% of behavioral willingness. Similar to our findings, in a study by Spijkerman et al., the adolescents’ prototypes of doing risky behaviors showed a positive relationship and could predict 13% of the variance of behavioral willingness to tobacco smoking and 15% of the variance of alcohol consumption (
21). Awareness of the adolescents’ mental prototypes about unhealthy role models can play an important role in the behavioral willingness toward risky behavior. In order to reduce the adolescents’ willingness to waterpipe smoking, preventive interventions should modify the adolescents’ prototypes and persuade them to replace these prototypes with healthy role models.
The results of this study showed that both behavioral willingness and behavioral intention could affect waterpipe smoking and explain 0.55 of the variance, and that behavioral intention was a stronger predictor than behavioral willingness. In most studies of the risky behaviors in adolescents, both the behavioral willingness and behavioral intention constructs had a strong relationship with unhealthy behaviors (
10,
19,
22-
24). However, the fact that which path could be a stronger predictor of the behavior was different in various studies. For example, similar to the present study, Andrews et al. introduced the behavioral intention as the significant predictor of cigarette smoking and alcohol consumption (
22), while in other studies the behavioral willingness was observed as the more powerful predictor of cigarette, waterpipe, and other forms of tobacco smoking (
10,
19). In addition, Pomery et al. considered the behavioral willingness as the predictor of substance abuse in early adolescence (at the age of 13) and the behavioral intention as the significant predictor of this behavior in middle adolescence (at the age of 16) (
23). The differences in demographic characteristics and the environment where the adolescent grows up are most likely to alter his decisions to get involved in risky behavior. For evaluating the factors affecting waterpipe smoking among adolescents and especially for planning educational interventions for them, it is important to pay attention to the impact of behavioral intention and behavioral willingness.
One of the limitations of the present study was using a self - report questionnaire for data collection. Furthermore, the participants were high school students who were in their mid-teens and may not be representative of all adolescents. It is recommended to conduct a similar study for early adolescence and lower grades.
5.1. Conclusion
The results of the present study revealed that the PWM constructs could provide an appropriate theoretical framework for identifying the factors associated with waterpipe smoking in adolescents. Both the intellectual and social reaction paths are effectively involved in the use or non - use of waterpipe in high school students; hence, the use of health promotion strategies in order to improve the individuals’ planning and intention for avoiding waterpipe smoking in the near future, as well as modifying their incorrect willingness through preventive interventions can help reduce waterpipe smoking in high school adolescents.