Table 1.

VT risk factors on Earth. Categorized as strong (OR > = 10); moderate (OR 2–9) or weak (OR < 2) Adapted from Table 3, Ortel et al.²⁸.

Weak risk factors	Moderate risk factors	Strong risk factors
Bed rest/immobility	Combined hormonal contraception/hormone replacement therapy	Prior VT
Age	Inflammatory/autoimmune diseases	Recent major surgery/major trauma
Varicose veins/venous insufficiency	Infections	Antiphospholipid syndrome/ Antithrombin deficiency
Superficial vein thrombosis	Congestive heart or respiratory failure	Active cancer15
Obesity	Venous catheters	Recent hospitalisation or more than a 3-day immobilisation for acute medical conditions
	Pregnancy or postpartum period	Neurological disease with extremity paresis9
		Genetic thrombophilia