Illicit Drug Use Among Gym-Goers: a Cross-sectional Study of Gym-Goers in Sweden

Study Design

The present study has a cross-sectional study design.

Participants and Procedure

In the spring of 2015, a questionnaire was distributed to gym-goers at 54 gyms in Sweden. The gyms were recruited either through Prevention of Doping in Sweden (PRODIS; a national network comprising governmental agencies, universities, county administrative boards, municipal prevention coordinators, representatives from the police force and gyms, the Swedish Sports Confederation, and the Swedish Anti-Doping Hotline) or through the research centre STAD (Stockholm Prevents Alcohol and Drug Problems). The questionnaire was distributed prior to implementation of the doping prevention programme 100% PHT at the gyms. During data collection, research staff stood by the entrance of the gyms on a weekday afternoon or evening and asked arriving gym-goers above 16 years of age whether they were going to do weight training (i.e., work with free weights or machines). Those who replied in the affirmative were invited to participate in the study. Gym-goers who agreed to participate were asked to complete a questionnaire. To guarantee anonymity, participants completed the questionnaire anonymously and then placed it in an envelope and sealed it, before returning it to the research staff. For the study, 2631 gym-goers were asked to participate, and 1969 of them agreed (74.8% response rate). All gyms were located in urban areas; 39% of the gyms were located in a major city (i.e., more than 200,000 inhabitants), 37% in a large town (i.e., more than 50,000 inhabitants), and 13% in a small town (i.e., more than 15,000 inhabitants) [27]. For more details on the data collection, please see study protocol [26].

Measures

The questionnaire distributed to the participants was based on another questionnaire previously used in a Swedish study measuring anabolic-androgenic steroid use among gym-goers [28]. It included 25 items on background variables, weight training frequency, use of illicit drugs, doping substances, and nutritional supplements, as well as attitude items on doping prevention. The questionnaire took 5 to 10 min to complete. The following measures were included in the current study:

Statistical Analysis

First, frequencies and proportions of demographic factors and weight training intensity are presented for the whole sample (n = 1969). Illicit drug use and associated characteristics are also presented for the whole sample. In a subsequent step, drug characteristics are presented only for those who reported illicit drug use (n = 385). Logistic regression models were then calculated in the whole sample (n = 1969) to examine associations between illicit drug use and weight training frequency, as well as associations between illicit drug use and use of doping substances. Crude odds ratios (OR) and 95% confidence intervals (95% CI) are presented. Odds ratios were then adjusted; when examining associations between illicit drug use and weight training frequency, odds ratios were adjusted for age and sex. When examining associations between illicit drug use and the use of doping substances, odds ratios were adjusted for age, sex, weight training frequency, and number of illicit drugs used. IBM SPSS Statistics 24.0 was used in all analyses. The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines were followed (S1).

Power Analysis

Previous studies have shown that the effect of prevention programmes is rather low, typically about 15–20% [29, 30]. To measure the intervention effect, a power analysis was carried out a priori; a minimum of 40 gyms (20 intervention gyms and 20 control gyms) and a minimum of 1600 participants (800 individuals per condition) were required at each data collection point to achieve a power of 80% at an alpha level of .05 (two-tailed). In the current pre-intervention study, 27 intervention gyms and 27 control gyms have been enrolled, and a total of 1969 individuals completed the questionnaire.

Ethical approval

The present study adheres to the criteria of the World Medical Association Declaration of Helsinki, and has been approved by the regional ethical review board of Karolinska Institutet, Sweden (registration number: 2016/142-31/3).

Discussion

In the present study, 1969 gym-goers at 54 gyms in Sweden completed a questionnaire covering the use of illicit drugs and prescription drugs. Results showed that 19.6% of gym-goers reported having ever used illicit drugs. Moreover, of this group, 6.5% reported use during the past 12 months and 2.1% during the past 30 days. Among those who reported illicit drug use, the most commonly used illicit drug was cannabis, followed by cocaine, amphetamine, and ecstasy. Furthermore, 5.1% of those reported a lifetime use of doping substances. Almost 40% of those reporting illicit drug use reported polysubstance use. Furthermore, male participants and participants between 16 and 39 years of age demonstrated significantly higher rates of illicit drug use and polysubstance use than female participants and participants above age 40, respectively.

Our findings are in line with two Swedish population-based surveys. In a survey from 2008/2009, 18% of respondents reported having used illicit drugs on at least one occasion in their lives [31]. In a survey from 2012, 3.1% of respondents had used an illicit drug during the past 12 months and 1.1% during the past 30 days [32]. Training at gyms is typically a health-promoting behavior; hence, it could be hypothesized that the estimates in our sample would be lower than the rates found in the general population. However, our results pointed to a slightly higher prevalence of illicit drug use among gym-goers. The elevated rates in our study could be explained by age and sex differences in the samples; our study included more males and more individuals from younger age categories, where illicit drug use is generally more prevalent [31, 32].

Conversely, participants in the present study reported a lower lifetime prevalence of illicit drug use as compared to the European average. In the European Union, approximately 25% of 15- to 64-year-olds are estimated to have used an illicit drug [33]. Studies consistently indicate lower estimates of illicit drug use in Sweden compared to many countries [34–36], which also could be reflected among gym-goers [24, 25]. Further research is needed to specifically examine the use of illicit drugs and prescription drugs (beyond benzodiazepines) in gym settings and to assess between-country differences as well as associations with demographic factors. Prevalence rates in our study were higher than rates among elite athletes in Europe and Australia [17, 18, 21]. Higher estimates of illicit drug use among gym-goers might be expected, however, as elite athletes generally have a healthier lifestyle and are also subject to anti-doping tests, which may have a deterrent effect on illicit drug use [18].

Two studies have examined the use of illicit drugs among gay male gym-goers in New York and London, respectively. In these studies, prevalence rates were markedly higher than in our study; in the New York study, estimates ranged between 6% (for hallucinogen use) and 35% (for inhalant nitrite use) during the past 6 months [24]. Among the men recruited from London gyms, 56% reported having used an illicit drug during the past 12 months [25]. It was proposed that these studies largely reflected a specific subculture among gay and bisexual men who frequented clubs and engaged in risk behaviors (i.e., substance use and sexual risk behavior), which could explain the higher prevalence rates.

The most commonly used illicit drugs in our study were cannabis, cocaine, amphetamine, ecstasy, and hallucinogens—drugs that can be used both as training aids or “body image drugs,” or recreationally as so-called club drugs [37–40]. Moreover, approximately 40% of the illicit drug users in our sample reported polysubstance use, and the rates were significantly higher among younger participants and males. Our results could also have captured a group of young adult males who focus on physical appearance and engage in partying and risk behaviors, comparable to the gay men in the gym studies discussed above. It has been suggested that drug use practices and weight training in a male “body subculture” can be understood as a way to construct a masculine identity and to achieve an idealized male body [41]. Our estimates were higher than the estimates in a study of anabolic substance use among 611 visitors to German fitness centers, where 15.9% reported using other illicit drugs [42]. Almost all participants in our study engaged in weight training, as opposed to 25% of the respondents in the German study. Again, the higher prevalence rates in our study could support the notion of a physical achievement-oriented group who engage in weight training and use illicit substances for ergogenic and/or recreational purposes.

In our study, however, we found no associations between weight training frequency and illicit drug use. Prior research on the association between physical activity and illicit drug use is mixed: Some studies suggest that the degree of sporting activity is negatively associated with substance use [43]. Others point to a curvilinear link between sporting activities and illicit drug use, i.e., that inactive and intensive levels are associated with greater use of illicit drugs than moderate levels are, particularly for strength sports (weightlifting and body-building) [19]. However, these studies have largely been based on adolescent populations, and it has been proposed that the relationship between physical activity and illicit drug use is affected by age [19], which could explain our differing results.

The overall prevalence of the lifetime use of doping substances (i.e., anabolic-androgenic substances and growth hormones) was lower in our total sample than in other gym samples [28, 42, 44–46]. Nonetheless, our results showed a threefold higher in odds of doping use among people who had reported illicit drug use as compared to non-users. Previous research has pointed to a strong relationship between use of doping substances and use of other illicit drugs [14, 47–49]. Illicit drugs may be used to increase or decrease the effects of anabolic-androgenic steroids (e.g., as pain relief to increase energy levels or to promote sleep) [6], and it has been proposed that doping prevention efforts should therefore address other illicit drugs as well [6]. The European Commission Group of Experts on Anabolic Androgenic Steroid Use in Recreational Sports has identified gyms as important target arenas for preventive efforts and has also suggested three key elements that should be included in research to inform policy, practice, and interventions: information on doping prevalence, use of other illicit drugs, and determinants and correlates [11].

Strengths and Limitations

The present study has both strengths and limitations that should be taken into account when interpreting the findings. One important strength is that we included a large sample of men and women and that participants were recruited from 54 gyms across the country. Limitations include a possible underestimation of illicit drug prevalence rates due to a higher degree of attrition among individuals who use illicit drugs or to recollection bias, social desirability, or fear that reported illicit drug use may attract unwanted attention to the gym [50]. Males and individuals under age 40 made up a large proportion of participants, which could limit the generalizability of the findings. Furthermore, the questionnaire was distributed on weekday afternoons and evenings, and only individuals who engaged in weight training were invited to participate, which could limit generalizability further. Although the questionnaire has been used in a prior study [28], its psychometric properties have not been validated. Another limitation was that the study was cross-sectional; thus, we could not establish causality in the association between illicit drug and doping use.