Doping in fitness sports: estimated number of unreported cases and individual probability of doping

Aims Recent studies have suggested that the use of doping substances and particularly of anabolic androgenic steroids (AAS) is often practised by fitness centre visitors. These studies employed direct interview techniques and questionnaires to assess the estimated number of unreported cases of doping. Because people hesitate to provide compromising information about themselves, these techniques are subject to response errors. In this study we applied an alternative interview technique to assess more accurately unreported cases of doping in fitness centres. Design and participants The present investigation employed the randomized response technique (RRT) to reduce response errors. A cohort of 500 people from 49 fitness centres participated in this study. Finding The RRT revealed a high prevalence of doping (12.5%). In addition, and most importantly, the present RRT study revealed an alarmingly high prevalence of illicit drug use, specifically of cocaine use, that has been severely underestimated by previous studies. Conclusions The RRT confirmed previously estimated rates of AAS use assessed by direct interview techniques and voluntary questionnaires, but uncovered a much higher usage rate of illicit drugs among fitness centre visitors. This outcome enabled us to construct a 'probability' rating for the use of doping substances in fitness centre visitors. Given its high prevalence and the predominant use of AAS, doping among fitness centre visitors is an issue of extreme relevance for the health care system. Our study may help to characterize further doping substance users and to develop and apply prevention and intervention programmes specifically to individuals at high risk.