Preventive medicine or preventive health care involves interventions that work at the level of the individual or the population to prevent diseases or pathology. This is in contrast to curative medicine and palliative medicine.
Most of the potential gain in health of human populations results from primary preventive medicine which includes public health methods such as sanitation and vaccination. Secondary preventive medicine commences after symptoms of a health problem present in an individual and often includes life style adjustment but increasingly medications that modify risk factors for disease.
Risk stratification for a population can be very useful but it must be remembered that usually the most effective way to alleviate the overall burden of illness in a population is to ensure appropriate resource effective interventions are directed at low and medium risk members of the population as well as those at high risk. So costly preventive therapies directed at those at high risk may actually be less effective with some illnesses than low cost life style interventions in those at low risk.