Rwenyonyi 1998.

Methods	FLUOROSIS STUDY Country of study: Uganda Geographic location: 4 areas of Uganda located at different altitudes Year of study: not stated Year of change in fluoridation status: NA Study design: cross‐sectional
Participants	Inclusion criteria: lifetime residents of study areas Exclusion criteria: none stated Other sources of fluoride: not stated Social class: not stated Ethnicity: not stated Residential history: lifetime residents Other confounding factors: mothers interviewed about water intake and food habits of child during early childhood; altitude
Interventions	All natural fluoridation Group 1: 2.5 ppm (low altitude) Group 2: 2.5 ppm (high altitude) Group 3: 0.5 ppm (low altitude) Control: 0.5 ppm (high altitude)
Outcomes	Dental fluorosis (index not stated) Age at assessment: 10‐14 years
Funding	The Norwegian Universities' Committee for Development Research and Education and the Committee for Research and Postgraduate Training, University of Bergen
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Sampling	Unclear risk	Children were selected from schools for study in a quasi‐random way
Confounding	High risk	While SES and use of fluoride toothpaste were reported as being similar across groups, there appeared to be a higher intake of tea (and therefore fluoride from water) among the participants in Kasese (0.5 ppm) than Kisoro (2.5 ppm)
Blinding of outcome assessment (detection bias) All outcomes	High risk	Insufficient information
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data appear to have been presented for all participants
Selective reporting (reporting bias)	Unclear risk	Outcome of interest was reported mainly in graphic form and was unclear
Other bias	Low risk	Examinations were carried out by a single examiner. Intra‐rater reliability was tested (kappa > 0.8)