The epidemiology of breast cancer; Review and prospects

In the epidemiology of a disease, which is multifactorial to such an extent as we believe breast cancer to be, attention should be paid even to “weak” factors and an attempt should be made to assign a place to them in an aetiologic system which is biologically sound. Medical knowledge will help us in doing this, and the exercises in “metabolic epidemiology” will be as useful as statistical manipulations and computer programming. Two developments seem to be taking place, one of them being the teamwork between analytic epidemiology and biochemistry; the other is that we are begining to realize that most so‐called chronic diseases of relatively high prevalence are like icebergs in the sea with a vast amount of subclinical abnormalities in the “healthy” population (and therefore in our control groups).