Fishing for the evidence on community water fluoridation: a commentary on the CATFISH study

Goodwin M, Emsley R, Kelly M P et al. Evaluation of water fluoridation scheme in Cumbria: the CATFISH prospective longitudinal cohort study. Southampton: National Institute for Health and Care Research, 2022.

This longitudinal, prospective cohort study, recruited two populations – a birth cohort and older school cohort – assessing the effects of community water fluoridation (CWF) over a five-year period. The control group received non-fluoridated drinking water in the East of Cumbria, while the intervention group received fluoridated drinking water in the West of Cumbria. The primary outcome measures were the presence or absence of decay into dentine in primary and permanent teeth. Cost effectiveness was assessed by quality-adjusted life-years.

Birth Cohort: Modest beneficial effect (17.4% with decay, 21.4% in control). Adjusted Odd Ratios (AOR): 0.74 (95% CI: 0.56 to 0.98).

Older Cohort: Insufficient evidence of difference (19.1% with decay and 21.9% in control). AOR: 0.80 (95% CI: 0.58 to 1.09).

The authors concluded that CWF was effective in the birth cohort and that the modest absolute reduction in caries should be considered in the context of other preventive measures. A longer follow-up period was recommended to fully understand the benefits and risks of CWF in contemporary low-prevalence populations.