Imo you were too vague in your conditions.
doi.org/10.1001/jamapediatrics.2024.5542
This systemic review and meta-analysis includes this (weak!!) negative health result even for the 1.5mg/L fluoride/water recommendation that WHO provides.
Sixty-four studies reported inverse associations between fluoride exposure measures and children’s IQ. Analysis of 59 studies with group-level measures of fluoride in drinking water, dental fluorosis, or other measures of fluoride exposure (47 high risk of bias, 12 low risk of bias; n = 20 932 children) showed an inverse association between fluoride exposure and IQ (pooled SMD, −0.45; 95% CI, −0.57 to −0.33; P < .001). In 31 studies reporting fluoride measured in drinking water, a dose-response association was found between exposed and reference groups (SMD, −0.15; 95% CI, −0.20 to −0.11; P < .001), and associations remained inverse when exposed groups were restricted to less than 4 mg/L and less than 2 mg/L; however, the association was null at less than 1.5 mg/L. In analyses restricted to low risk-of-bias studies, the association remained inverse when exposure was restricted to less than 4 mg/L, less than 2 mg/L, and less than 1.5 mg/L fluoride in drinking water. (emphasis added)
I would personally consider this to qualify, though I will understand if you want to be more strict.
shads@lemy.lol 2 days ago
Oh god, my brother started spouting this nonsense at the same time he went vegan (which I don’t have a problem with) and anti-vax (which I REALLY do). He was also really eager to tell me all about how iodised salt was a conspiracy by the government to lower the IQ of the population. Oh and don’t get me started on his take on 9/11.
I wound up telling him I wouldn’t discuss anything further with him unless he could bring receipts.