[bjourne]

Fluoridated drinking water may explain the difference.

[gcanyon]

Fun fact: I'm visiting Uruguay right now, and they have fluoridated salt here! (it's iodized as well)

[dtech]

UK tap water isn't fluoridated

[ljf]

Not strictly true: https://www.dwi.gov.uk/consumers/learn-more-about-your-water...

Quote:

The water companies that are currently required by the Secretary of State to fluoridate some or all of their water supplies are:

United Utilities

Northumbrian Water

Anglian Water

Severn Trent Water

South Staffordshire Water

[thorin]

This isn't entirely true: https://www.gov.uk/government/consultations/community-water-...