Evaluation of optimal water fluoridation on the incidence and skeletal distribution of naturally arising osteosarcoma in pet dogs.

Experimental toxicological studies in laboratory animals and epidemiological human studieshave reported a possible association between water fluoridationand osteosarcoma (OSA). To further explore this possibility, a case-control study of individual dogs evaluated by the UC Davis Veterinary Medical Teaching Hospital was conducted using ecologic data on water fluoridationbased on the owner's residence. The case group included 161 dogs with OSA diagnosed between 2008-2012. Two cancer control groups included dogs diagnosed with lymphoma (LSA) or hemangiosarcoma(HSA) during the same period (n = 134 and n = 145, respectively). Dogs with OSA were not significantly more likely to live in an area with optimized fluoridein the water than dogs with LSA or HSA. Additional analyses within OSA patients also revealed no significant differences in age, or skeletal distribution of OSA cases relative to fluoridestatus. Taken together, these analyses do not support the hypothesis that optimal fluoridationof drinking water contributes to naturally occurring OSA in dogs.