World Health Day is celebrated on 7 April to mark the anniversary of the founding of WHO in 1948. Each year a theme is selected for World Health Day that highlights a priority area of public health concern in the world. The theme for 2013 is high blood pressure. High blood pressure increases the risk of heart attacks, strokes . If left uncontrolled, high blood pressure can also cause blindness, irregularities of the heartbeat and heart failure. The risk of developing these complications is higher in the presence of other risk factors such as diabetes . One in three adults worldwide has high blood pressure and this increases with age, from 1 in 10 people in their 20s and 30s to 5 in 10 people in their 50s. High blood pressure is most common in some low-income countries in Africa, with over 40% of adults in many African countries thought to be affected. However, high blood pressure is both preventable and treatable. In some developed countries, prevention and treatment of it has brought about a reduction in deaths from heart disease. The risk of developing high blood pressure can be reduced by: reducing salt intake; eating a balanced diet; avoiding harmful use of alcohol; taking regular physical activity; keeping a healthy body weight; and avoiding tobacco use. The final and most important goal of World Health Day 2013 is to reduce heart attacks and strokes, which includes as follows: 1.to raise awareness of the causes and consequences of high blood pressure; 2.to provide information on how to prevent high blood pressure 3.to encourage adults to check their blood pressure and to follow the advice of health-care professionals. The text is mainly about  _  .
the theme for World Health Day 2013 the causes of high blood pressure the treatment of heart attacks and strokes how to reduce the risk of high blood pressure