Question

All of the following are risk factors for deep vein thrombosis (DVT) except -

• A. Duration of surgery more than thirty minutes
• B. Obesity
• C. Age less than forty years
• D. Use of the oestrogen-progesterone contraceptive pills

Hint:

Advanced age, not youth, is the venous-clot risk factor.

Answer 1

The Correct Option is C

Step 1: The question asks which option is NOT a recognised risk factor for deep vein thrombosis (DVT). Virchow's triad explains DVT - venous stasis, endothelial injury, and a hypercoagulable state. Any factor that promotes one of these increases risk.

Step 2: Prolonged surgery (more than 30 minutes) causes immobility and venous stasis, obesity adds stasis and a low-grade prothrombotic state, and combined oestrogen-progesterone contraceptive pills raise clotting factor levels. All three are well established risk factors.

Step 3: Age is a risk factor only when it is ADVANCED. Risk rises sharply after 40 to 60 years of age. Age LESS than 40 years is actually protective, so it cannot be a risk factor.

Step 4: Therefore the exception is age less than forty years, which is option (c).