HC Deb 09 May 1961 vol 640 c209
23. Mr. Matthews

asked the Parliamentary Secretary for Science what knowledge has been gained by the Medical Research Council about the relationship between the hardness of local water supplies and mortality from diseases of the heart and arteries.

Mr. Denzil Freeth

A recent statistical inquiry undertaken by the council in the county boroughs of England and Wales has shown that the death-rate from cardiovascular disease tends to be higher in areas with soft water supplies. It is not yet known, however, whether the relationship between water softness and cardiovascular disease is one of cause and effect.