Detection of emerging patterns of drug misuse in sports via wastewater monitoring: A mini-review and potential strategies.

Biological testing is a key component of the current anti-doping programme implemented by the authorities to detect doping in sports. Strategies such as longitudinal individualised data analysis and sport-specific analysis have been developed to increase the comprehensiveness of the testing. However, the trends of drug misuse in sports might not be effectively captured through today's testing plan. Wastewater testing, assembling individual-level data of a designated group to produce population-level results in one single aggregated sample, can be employed to as a complementary strategy offering added value for doping control. This paper presents an updated summary of the status of anti-doping testing and analytical methodologies for wastewater. The available literature on wastewater-based analyses of drugs prohibited in sports is reviewed. Publications surrounding sporting activities or competitions and others relevant to sports doping are selected. We debate between potential strategies and major limitations of using wastewater monitoring in anti-doping. Knowledge gaps and research directions, specifically on metabolites, stability, sensitivity, and ethical and legal considerations, are discussed. Choosing different wastewater sampling sites allows target sub-population that involved competing athletes and potentially reveal sport-specific or athlete-level-specific behaviour. Sampling from on-board toilets or athlete villages could target international-level athletes, sampling from the dormitories of national training centres allows monitoring of national-level athletes on a daily basis, and sampling from sports stadiums provides a full picture of drug use in the general population during an event. Confounding occurs as (i) the presence of non-athlete composition and the difficulty of analyses to be completely selective to the athlete population; and (ii) the identification of compounds prescribed legitimately with Therapeutic Use Exemptions, only banned in-competition, and naturally occurring. The practicalities of the approach are contextualised in monitoring the non-threshold substances such as anabolic agents, selective androgen receptor modulators, metabolic modulators, and hypoxia-inducible factor activators.