Precision and non-ambiguity are paramount adjuncts of word usage and scientific communication, particularly when the term coronary heart disease (CHD) is in common use epidemiologically and as an end point in clinical trials. CHD, as non-sensical as “femoral leg disease”, may have led non-medical epidemiologists to consider it a specific disease when this is pathologically false.

“Disease” can be used in a general sense to indicate a diseased state, the antithesis of health. “A disease” should signify a specific disease entity (such as atherosclerosis) and should not be used loosely in reference to symptoms (angina pectoris, headache), signs (fever, hypertension), laboratory findings (hypercholesterolaemia), non-specific complications (embolism, haemorrhage, ischaemia, necrosis), pathological lesions (gangrene, aneurysm, infarct, haematoma), abnormal functional states (obstructive lung disease) or collective terms for pathological states or diseases related to an organ (renal disease, cerebrovascular disease, CHD). Each exclusion is a manifestation of many specific diseases varying aetiologically and pathogenetically. Some are non-specific clinical diagnoses, not specific disease entities. Loose usage cannot be condoned.

Disease classification based on aetiological or pathogenetic mechanisms is preferable to classification based on anatomical sites, functional changes or non-specific pathological lesions. Aneurysm and subarachnoid haemorrhage cannot be treated clinically or epidemiologically as single disease entities for each is a non-specific complication of many diseases (even trauma). Pooling diverse diseases that cause aneurysms for epidemiological or therapeutic study is unwise and this holds true for myocardial ischaemia that cannot be used to infer the presence of coronary atherosclerosis of any given severity nor …