Table 5

A summary of risk factors and biomarkers associated with ARill and ARinf (suspected and confirmed) for which there is strong evidence of a positive association, no association or both

Pathological classificationStrong evidence supporting a positive associationStrong evidence supporting no associationStrong evidence supporting both a positive association and no association
General (undiagnosed) ARill
(Table 5a)
  • Less competitive athletes

  • Elevated neutrophil and WBC counts

  • Low serum (vitamin D)

  • Intensified training phase

  • Competition

  • Reduction in salivary flow rate

  • Detection of IgE antibodies to aero-allergens

  • Increased training load

Suspected ARinf
(Table 5b)
  • Less competitive athletes

  • Decreased training intensity

  • Increased training monotony

  • Endurance preparation phase

  • No tapering phase

  • Winter

  • Exposure to high altitude

  • International travel

  • Previous respiratory infections

  • Low serum (vitamin-D)

  • Age

  • Gender

  • Household family exposure

  • Increased training load

  • Increased strength and speed training

  • Competition period

Confirmed ARinf
(Table 5c)
  • Increased training intensity

  • Lower salivary-(IgA) preseason and pretraining and decline across a training programme

  • Reduced tear-(SIgA) and secretion rate

  • Post-season salivary-(IgA)

  • ARill, acute respiratory illness; ARinf, acute respiratory infections; WBC, white blood cell.