Question: Who is at risk for Polycythemia Vera? ?
Answer: Polycythemia vera (PV) is a rare blood disease. The disease affects people of all ages, but it's most common in adults who are older than 60. PV is rare in children and young adults. Men are at slightly higher risk for PV than women.
Source: NHLBI

Question: How to prevent Polycythemia Vera ?
Answer: Primary polycythemia (polycythemia vera) can't be prevented. However, with proper treatment, you can prevent or delay symptoms and complications. Sometimes you can prevent secondary polycythemia by avoiding things that deprive your body of oxygen for long periods. For example, you can avoid mountain climbing, living at a high altitude, or smoking. People who have serious heart or lung diseases may develop secondary polycythemia. Treatment for the underlying disease may improve the secondary polycythemia. Following a healthy lifestyle to lower your risk of heart and lung diseases also will help you prevent secondary polycythemia.
Source: NHLBI