Why is breast cancer so frequent in The Netherlands?

The very high incidence rate of breast cancer in The Netherlands, and in other Western industrialized countries, has to be explained by promoting environmental factors. The possible contributions by hormones and nutrition are reviewed. It is concluded that the promotion of breast cancer is likely to occur during breast development and several subsequent decades. A hypothesis is discussed which could explain how the affluent Western diet, a relative lack of physical activity and possibly also an overall increase of stress lead to a greater bio-availability of oestrogens at normal plasma concentrations. In this model the decrease of sex hormone binding globulin and a change of the binding equilibrium between oestrogens and plasma proteins in the presence of free fatty acids are central. Intra-abdominal fat accumulation, or frank central obesity, would favour this mechanism. Leads to further investigation and preliminary results are presented.