Much is known about the prevention of NCDs. Experience clearly shows that they are to a great extent preventable through interventions against the major risk factors and their environmental, economic, social and behavioural determinants in the population. Countries can reverse the advance of these diseases if appropriate action is taken.

Strategies to reduce exposure to established risk factors and to lower the risk for individuals who present clinical signs of further progression of these diseases, even when implemented together, do not achieve the full potential for prevention. A comprehensive long-term strategy for control of noncommunicable diseases must therefore necessarily include prevention of the emergence of risk factors in the first place.

In any population, most people have a moderate level of risk factors, and a minority have a high level. Taken together, those at moderate risk contribute more to the total burden of noncommunicable diseases than those at high risk. Consequently, a comprehensive prevention strategy needs to blend synergistically an approach aimed at reducing risk factor levels in the population as a whole with one directed at high-risk individuals.

Review of studies has shown that, for substantial reductions in the levels of risk factors and in disease outcomes, delivery of interventions should be of appropriate intensity and sustained over extended periods of time. However, even modest changes in risk factor levels will have a substantial public health benefit, and often already within a few years.

Experience indicates that success of community-based interventions requires:

• community participation
• supportive policy decisions
• intersectoral action
• appropriate legislation
• health care reforms
• collaboration with NGOs, industry and the private sector
• close links with national health policy

Decisions made outside the health sector often have a major bearing on elements that influence the risk factors. More health gains in terms of prevention are achieved by influencing public policies in domains such as trade, food and pharmaceutical production, agriculture, urban development, and taxation policies than by changes in health policy alone.