Bone cancer incidence rates in New York State: time trends and fluoridated drinking water. BACKGROUND: Recent animal studies of the potential carcinogenicity of fluoride prompted an examination of bone cancer incidence rates. METHODS: Trends in the incidence of primary bone cancers, including the incidence of osteosarcomas were examined among residents of New York State, exclusive of New York City. Average annual osteosarcoma incidence rates in fluoridated and non-fluoridated areas were also compared. RESULTS: Among persons less than 30 years of age at diagnosis, bone cancer incidence among males demonstrated a significant increase since 1955, while incidence among females has remained unchanged. A significant decrease in bone cancer incidence rates since 1955 was observed among both males and females age 30 years and over at time of diagnosis. Osteosarcoma incidence rates have remained essentially unchanged since 1970, among both younger and older males and females. The average annual age adjusted incidence of osteosarcomas (1976-1987) in areas served by fluoridated water supplies was not found to differ from osteosarcoma incidence rates in non-fluoridated areas. CONCLUSIONS: These data do not support an association between fluoride in drinking water and the occurrence of cancer of the bone. 