A study of osteosarcoma cases occurring between 1994 and 2006 across the whole of Ireland (Irish Republic and Northern Ireland) found no significant differences between fluoridated and non-fluoridated areas. (1)

Published in 2011, the study found no significant differences between fluoridated and non-fluoridated areas in any 5-year age-specific rate for either males or females, and no differences in overall age-standardised incidence rates.

The study authors concluded: “The results of this study do not support the hypothesis that osteosarcoma incidence in the island of Ireland is significantly related to public water fluoridation.”

Around 70% of people living in the Irish Republic are supplied with fluoridated water at optimal levels for dental health.  Around 30% of the population – mainly in rural areas with private water supplies – do not receive fluoridated water.  There are no community water fluoridation schemes in Northern Ireland.

Commenting on the possible causes of osteosarcoma, the authors said that radiation, some rare genetic disorders and possibly viral infection are the only established factors.  They point out that variations in incidence rates between different countries are low, suggesting that external environmental agents play only a minor role.

1. Comber H, Deady S, Montgomery E, Gavin A (2011): Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer Causes Control, 22, 919-924.