OBJECTIVE: Our goals were to determine the prevalence of ergogenic supplement use in a young healthy population and to examine the extent to which supplement use is associated with specific health risk behaviors.
STUDY DESIGN: We performed a cross-sectional survey.
POPULATION: Individuals entering military service for enlisted training were included.
OUTCOMES MEASURED: We recorded previous use of any nutritional ergogenic supplements and self-reported health risk behaviors.
RESULTS: Of 550 eligible participants, 499 completed the survey (91% response rate). Individuals who used ergogenic supplements were more likely to drink alcohol (adjusted odds ratio [AOR]=1.8; 95% confidence interval [CI], 1.1-3.1), more likely to drink heavily (AOR=2.4; 95% CI, 1.5-3.9), more likely to ride in a vehicle with someone who had been drinking (AOR=2.2; 95% CI, 1.3-3.6), more likely to drive after drinking (AOR=2.4; 95% CI, 1.3-4.4), and more likely to have been in a physical fight (AOR=1.9; 95% CI, 1.0-3.5), compared with those who had not used supplements. Men were more likely to use supplements than women (P <.001). There were no differences in patterns of supplement use according to age or body mass index.
CONCLUSIONS: Our study indicates an association between individuals who use ergogenic nutritional supplements and specific health risk behaviors. This represents an important opportunity for preventive counseling.
Since ancient times, athletes have ingested substances to gain a competitive edge.1 The use of such supplements, however, is not restricted to athletes. In 1996, Americans spent $6.5 billion on dietary supplements.2 Individuals cite many reasons for using such supplements, including to ensure good nutrition, prevent illness, improve performance, ward off fatigue, and enhance personal appearance.3
Since 1998, interest in the ergogenic effects of products currently marketed as nutritional supplements, in particular creatine and androstenedione, has increased. Creatine is currently the most popular dietary ergogenic supplement.4 The reported benefits of creatine include increased energy during short-term intense exercise, increased muscle mass, increased strength, increased lean body mass, and decreased lactate accumulation during intense exercise. Although it is clear that supplementation raises intramuscular creatine stores,5 it remains unclear how effective creatine is as an ergogenic aid. Generally, it is felt that creatine supplementation may be useful for repeated bouts of high-intensity short-duration exercise.6 Claims of increased strength and muscle mass have not, however, been unequivocally proven.
Androstenedione is a steroid hormone. Many sporting communities, including the International Olympic Committee, have banned its use. By itself, androstenedione is weakly androgenic. To date, the largest controlled trial examining the effectiveness of androstenedione as an ergogenic aid showed no significant gains in muscular strength compared with a standard program of resistance training.7 Methodologic concerns have been raised about this particular study,8 because supplement manufacturers are not subject to United States Food and Drug Administration approval if no unsupported claims of efficacy are made. Therefore, sales of ergogenic supplements remain brisk.
Within this context, our study was designed to examine the prevalence of ergogenic supplement use in a young population. We also sought to determine the extent to which supplement use was associated with personal health risk behaviors and to determine how effective ergogenic supplements were perceived to be.
Methods
Sample Recruitment
Our study was conducted at Lackland Air Force Base, Texas, and Parris Island, South Carolina, from June through September, 1999. All men and women entering military basic training at these sites were eligible to participate. Individuals were randomly selected to receive the survey. There were no specific exclusion criteria.
Survey Administration
The Youth Risk Behavior Survey (YRBS)9 was modified for use in our study. Specifically, questions about nutritional ergogenic supplement use were added to the standard instrument that is used to examine health risk and preventive behaviors, such as tobacco use, alcohol use, seat belt use, helmet use, and suicide. The subjects were specifically asked to report use of creatine and androstenedione. They were also given an open-ended opportunity to report any other ergogenic supplement use.
Data Analysis
We used basic descriptive statistics for categorical variables. Proportions were compared using the chi-square test of contingency. The Fisher exact test was used for rare responses. Continuous variables were compared using the Student t test for independent samples. We calculated adjusted odds ratios with a multivariate logistic regression analysis controlling for sex, age, and body mass index.
Results
Of 550 individuals recruited for participation, 499 (91%) completed the survey. The respondents ranged in age from 17 to 35 years (mean age = 21 years). The study sample was 88% men (n=439) and 12% women (n=60). The lifetime prevalence of ergogenic supplement use in our study population was 41%. Creatine was the most commonly used ergogenic supplement (n=117; 23% of the study sample), followed by androstenedione (n=38; 8%).