Preventive medicine

Most deaths before age 80 years are preventable.

Childhood and early adult life

Deaths from infectious diseases and trauma usually reflect poverty and political instability. Prevention requires political action to reduce the risk of war and improve the supply of food, clean water, sanitation, and shelter. Preventive medicine can augment, but not replace, this action by controlling spread of infection through vaccination, health education, control of insect vectors, and treatment of disease carriers to prevent onward transmission.

Middle age

The commonest cause of premature death is vascular disease—mainly heart attacks and stroke. The main causes are obesity, a high-fat diet, and tobacco smoking rather than starvation and lack of clean water. In this context political action is still very important to make it easy for people to take exercise and eat healthily, and to make it difficult for people to buy and smoke tobacco.

Preventive medicine

This can identify and treat people at increased risk of death from vascular disease (particularly those with diabetes, high blood pressure, and high blood lipids) and will save many lives by doing this effectively, but the need for medicines to treat vascular disease in individuals is a measure of public health failure. The coexistence of obesity and starvation as major causes of preventable mortality in many countries is a growing public health challenge. Many effective preventive interventions, such as legislation to make seatbelts compulsory or tax tobacco, should be targeted at the whole population, but preventive medicine provided by clinicians must target individuals. This often requires screening to detect early signs of disease (e.g. HIV infection, cancer) or markers of risk of disease (e.g. high blood pressure, intrauterine growth delay), but clinicians must be clear that something effective can be done to ameliorate the condition detected before any screening is undertaken (see Chapter 3.3.2).

Failure of evidence-based preventive interventions

The usual reason for failure is lack of effective implementation, with the three most important implementation failures being: (1) poor population coverage (only a small proportion of the at-risk population receiving the intervention); (2) inadequate staff training; and (3) inadequate quality control.

Preventive medicine and curative medicine

Preventive medicine is an important and integral part of good curative medicine. All doctors have a responsibility to think about why someone is ill. Whatever disease is diagnosed, the question of whether it could have been prevented, and whether the risk of progression can be reduced, must be addressed. For example, every clinician who diagnoses a stroke must ask themselves whether a previous clinical opportunity to measure and control blood pressure has been missed, and reflect on this in regard to their future practice relating to other patients.