In this paper, we have presented the prevalence and predictors of the use, and intentions to use protein powder, creatine, and anabolic steroids among Australian adolescent boys. We found that half of our participants had used protein powder, and that 62% intended to use protein powder. Use of creatine and anabolic steroids was lower than use of protein powder, but greater proportions of participants reported intentions to use these products. We found that the number of sports that boys participated in, and engagement in weightlifting, were the strongest statistical predictors of use, and intentions to use protein powder, more so than body esteem, drive for muscularity, age, ethnicity, or BMI. Our hypotheses were partially supported, in that sports participation and weight training, as well as drive for muscularity, were significant predictors of use, and intentions to use protein powder, but contrary to our hypotheses, body esteem was not.
The prevalence of the use of protein powder in this universal school sample is much higher than prevalence from data collected among a US sample 5 years ago. In the Project Eat study, 34.7% of adolescent boys (mean age 14 years) were using protein shakes and 5.9% reported using steroids (30). The prevalence found in our study was more closely aligned with an Australian sample from a similar time period, that found that 42% of adolescent athletes (13-18 years) had used whey protein powders, 29% consumed protein bars, and 29% used pre-mixed protein drinks (4). Replication with other universal samples will be required to determine whether supplement use is higher among Australian adolescent boys than adolescent boys from the US or elsewhere, or whether usage rates are increasing over time.
Our findings that sports participation and weight training were associated with greater use, and intentions to use protein powder is consistent with past research with adolescent boys which has also generally found that those who are playing sports are more likely to use muscle building substances. However, the exact nature of the association is not yet clear. In the Project Eat study, adolescents participating in sports were significantly more likely to report muscle-enhancing behaviours, including the use of protein powder (14). In their systematic review of the factors predicting the use of doping and performance enhancing substances in young people, Nicholls and colleagues found that the relationship between sports participation and doping use was unclear. Of the five studies that were reviewed, some found no differences among athletes and non-athletes, higher use among athletes, or higher use among non-athletes (22). The review did, however, demonstrate that consistent with our findings, there was a clear relationship between engagement in strength-based sports and activities, for example weight training, American wrestling, and American football, and PIED use (22).
Our study findings are consistent with past literature that has reported greater supplement use in adolescents with body dissatisfaction (24). Our findings add greater specificity to past literature by demonstrating that muscularity beliefs, but not body esteem, were associated with higher intention to use, and actual use of protein powders. This distinction is important, as it demonstrates that it is the specific focus on concerns about muscularity, rather than general perceptions about appearance that are related to engagement in body change strategies in adolescent boys. This distinction provides a useful insight into potential targets for intervention, suggesting that improving body image in general, rather than focusing on muscularity specifically, would be likely to be less effective to address supplement use.
The supplements and doping literature is filled with examples of limitations to research due to the nature of the questions and scales used, and this research is no different. Given the time constraints, and limited attention span of adolescent boys, it is important that questionnaires are kept as short as possible, but this means that we miss out on layers of detail from not having the capacity to ask multiple questions in different ways. In this study, we asked direct questions about the use, and intentions to use protein powder, creatine, and anabolic steroids, but it is possible that there are better means of determining this information. Questions about sport participation could also have been more specific, in order to determine the level (amateur, recreational, elite, etc) and amount of the sport played (occasionally, one per week, etc). Finally, the numbers of boys consuming creatine and anabolic steroids were too low to allow us to complete regression analyses to predict the use of these products.
Our findings of high use of protein products in mid-adolescent boys have implications for the development and implementation of education, prevention, and intervention programs in a range of settings. First, this research justifies the inclusion of education about PIEDs and supplements in the school curriculum, aimed at a universal audience. In terms of timing, our findings of relatively high protein powder use among 14-16 year-old adolescents suggests that it is important that intervention and education programs to prevent supplement use take place when boys are 12-13 years old, before these attitudes and behaviours are established.
Our research found that adolescents who were engaged in weight lifting were particularly more likely (3.8 times) to be engaging in current protein powder use. This presents an opportunity to engage a potentially high-risk group of boys in selective intervention program to prevent current harm, and future PIEDs use. Education and professional development programs for teachers, personal trainers, gym and fitness centre staff, and coaches is also required in order to support programs targeted at boys. Whole-of-centre approaches towards making gyms, fitness centres, and other settings where weight lifting occurs more supportive of health (as opposed to appearance-related) motivations for physical activity are also advised.
In terms of the content of education programs, it is suggested that we look towards other evidence-based drug education programs that have been found to prevent the use of drugs and alcohol use among adolescents. Some school-based drug education programs designed for universal groups, regardless of their risk level, have produced small to moderate effects in terms of health behaviour change (31, 32). Specific doping prevention interventions have also been effective, for example the Hercules program (33), and the Athletes Training and Learning to avoid Steroids [ATLAS] program (34), indicating potential directions for prevention programming.