GROWTH AREAS IN HYPERTENSION

Essential hypertension is an arbitrarily defined disorder to which bot h environmental and genetic factors contribute. Identifying these fact ors is a difficult task because individually their contribution is rel atively small and apparent causality may be the result of secondary ch anges or genetic drift. Associations between elevated blood pressure a nd genetic or phenotypic characteristics are insufficient therefore to demonstrate a cause and effect relationship. This conclusion requires that stringent criteria are met including the presence of the abnorma lity at or before the first manifestation of hypertension, co-segregat ion of the relevant gene, reversibility of hypertension when the abnor mality is removed (at least during the early phases of hypertension) a nd failure of the abnormality to resolve with the correction of hypert ension. It is proposed that these conditions constitute 'Koch's postul ates' for defining the causes of elevated blood pressure.