A chara, – Declan Waugh (June 20th) raises a number of interesting points regarding the interpretation of peer-reviewed scientific articles.
Far from finding that “fluoride was the main factor in calcification of the major arteries”, the article to which he referred simply notes that there is a correlation between fluoride uptake in vascular walls and arterial calcification; no causation was established.
It is easy to confuse correlation and causation, but the two are not the same. Just because ice-cream vendors sell more ice-creams on a sunny day (ie correlation), it doesn’t follow that high ice-cream sales cause the sun to come out (ie causation).
He also neglected to mention that the article referred not to the low levels of fluoride in public water supplies, but to high concentrations of radioactive fluoride ions injected into patients undergoing PET and CT scans. Equating these things makes as much sense as suggesting that we shouldn’t drink the occasional glass of lemonade just because a once-off intravenous lemonade drip was likely to cause serious health difficulties.
It is easy to forget that water fluoridation provides significant dental health benefit, and even easier to make alarmist allegations about its safety. However the scientific evidence of its safety is extremely well established, and fluoridation of public water supplies rightly deserves to be hailed as one of the great public health achievements of the 20th century. – Is mise,
N ICK HILLIARD,
De Courcy Square,
Glasnevin,
Dublin 9.