Spatial distribution and temporal variation of high fluoride contents in groundwater and prevalence of fluorosis in humans in Yuanmou County, Southwest China

► High F contents in water and fluorosis in humans occurred in lowland Yuanmou County. ► Fluoride levels and fluorosis prevalence dropped due to a supply of safe water. ► Fluorosis is positively associated with high fluoride levels in drinking water. ► Supply of safe drinking water is an effective way to reduce fluorosis. ► It is essential to enhance awareness of health risks posed by high F levels in water.