Cancer mortality in England in relation to levels of naturally occurring fluoride in water supplies

SUMMARY Sixty-seven small areas in England have been classified into four groups according to the level of naturally occurring fluoride in their water supplies. Small area mortality statistics for 1969-73 have been used to look for differences in cancer mortality in relation to fluoride levels. Deaths from all cancers and from cancer at 12 specific body sites have been examined; no consistent trends in mortality are apparent. These results provide no evidence of a harmful effect of naturally occurring fluoride in water supplies. A number of recent studies have searched for but failed to find an association between fluoride in water supplies and an increased risk of cancer.'-4 These studies have, however, all dealt with artificially fluoridated water supplies, and there is advantage in investigating naturally occurring fluoride and cancer mortality or incidence, as did a number of earlier studies in the United States and Britain,5 9 since the populations have generally been exposed fo