Arif 2013.

Methods	FLUOROSIS STUDY Country of study: India Geographic location: Nagaur district Year of study: 2013 Year of change in fluoridation status: NA Study design: cross‐sectional
Participants	Inclusion criteria: only villages where the mean fluoride concentration was > 1.0 mg/L were selected for the dental fluorosis survey. No other information provided for participants Exclusion criteria: not stated Other sources of fluoride: not stated Social class: not stated Ethnicity: not stated Residential history: not stated Other confounding factors: not stated
Interventions	54 villages receiving water with different natural fluoride concentrations ranging from 0.9 5.8 ppm
Outcomes	Dental fluorosis (Dean's Index) Age at assessment: not stated
Funding	Not stated
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Sampling	Unclear risk	Only villages where the mean fluoride concentration was > 1.0 ppm were selected. There was insufficient detail reported to determine how selection took place
Confounding	High risk	Did not account for use of other fluoride sources or SES
Blinding of outcome assessment (detection bias) All outcomes	High risk	Insufficient information
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient information to determine whether data presented for all participants as study details were poorly reported
Selective reporting (reporting bias)	Low risk	Outcome of interest not reported in paper, but made available by authors via email
Other bias	High risk	Fluoride concentration for the different villages overlapped making the data impossible to interpret