| AR: The excess risk of disease in those exposed compared with those unexposed—for example, the additional risk of SCD in athletes resulting from their participation in competitive athletics. | Ie − Io |
| ARF: The proportion of disease among the exposed that is attributable to the exposure—for example, the proportion of SCD that could be prevented by disqualifying athletes from competition. | (Ie − Io)/Ie |
| PAR: The excess risk of disease in the total population of exposed and non-exposed individuals that is attributable to the exposure—for example, the extra risk of SCD in the total population (athletes and non-athletes) as a result of competitive athletics. | Ip−Io |
| PARF: The proportion of disease in the total population that is attributable to the exposure—for example, the proportion of SCD in the total population that could be prevented by disqualifying athletes from competition. | (Ip − Io)/Ip |
| NNS: The number of people in a population who need to be screened to prevent one person from dying or improving their outcome. | 1/(Ie−Io) |
Key:
Ie—Incidence in exposed—for example, athletes Io—Incidence in the non-exposed—for example, non-athletes Ip—Incidence in the population—for example, exposed and non-exposed All measures assume causality between exposure and outcome (ie, participation in competitive athletics and SCD)
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