HC Deb 25 October 1973 vol 861 c614W
Mr. Knox

asked the Secretary of State for Social Services what is the incidence of mongol births in areas of England and Wales where fluoridation of the water supply has been in force for five years or more, compared with areas where sodium fluoride is not added.

Sir K. Joseph

No general figures are available, but a study covering 10 years of three areas in England with fluoride levels in the water of between 0.7 and 2.0 ppm and six areas with 0.2 ppm or less revealed no evidence of any relationship between the fluoride level and the incidence of mongolism.