Fluoridation may not be linked with adverse health outcomes. 
Community water fluoridation and health outcomes in England: a cross-sectional study.  Young N, Newton J, Morris J, Morris J, Langford J, Iloya J, Edwards D, Makhani S, Verne J. Community Dent Oral Epidemiol 2015; 43:550-9.  Public Health England TYPE OF STUDY/DESIGN: Ecological (area based).