Environmental factors in the development of essential hypertension.

Hypertension is predominantly a disorder of populations in which the fundamental problem is the tendency for blood pressure to rise with age. This phenomenon, which varies markedly across populations, is determined largely by environmental factors. We argue that the most important factors in the development of hypertension at the population level are calorie excess (as manifest by obesity), high salt intake, low potassium intake, physical inactivity, heavy alcohol consumption and psychosocial stress. Potential interactions between these factors (and the genetic endowment) are emphasized. We consider data from studies of blood pressure in children and adolescents and from intervention studies. The hypothesis that essential hypertension is initiated in fetal life is reviewed briefly. It is clear that the current high risk approach to prevention should be supplemented by a population based approach. There is controversy however regarding the value of certain interventions, such as salt restriction, at the population level. Ultimately community intervention trials will be required to resolve these issues.