. Author manuscript; available in PMC: 2014 Dec 9.

Published in final edited form as: Nat Rev Rheumatol. 2014 Apr 1;10(7):403–412. doi: 10.1038/nrrheum.2014.36

Table 2. Examples of risk factor paradoxes in nonrheumatic disease contexts.

Risk factor paradox	Associations in the general population	Associations in the index population
Smoking paradox	Risk of incident CAD	↓ Risk of hospital mortality in patients with CAD²⁸
Obesity paradox	Risk of incident CAD	↓ Risk of cardiovascular-specifc mortality in patients with CAD^29,30
Aspirin paradox	Risk of incident COPD	↓ Mortality in patients with COPD⁶⁵
Thrombophilia paradox	Risk of incident CHD	↓ Risk of recurrent CHD events in patients with CHD⁶⁶
PFO paradox	Risk of incident VTE	↔ Risk of recurrent VTE in patients with incident VTE³⁵
Low birth-weight paradox	Risk of incident stroke Risk of low-birth weight baby	↔ Risk of recurrent stroke in patients with incident stroke^31,32↓ Mortality in low-birth weight babies³⁶
Apolipoprotein E4 allele	Risk of incident Alzheimer disease	↓ Risk of Alzheimer disease progression^33,34

Abbreviations: CAD, coronary artery disease; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; PFO, patent foramen ovale; VTE, venous thrombotic embolism.