Non-communicable diseases: fluoride in drinking water: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Non-communicable diseases: fluoride in drinking water

Sample item

The WHO guideline value for fluoride in drinking water, above which the risk of dental and skeletal fluorosis increases, is:

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. 1.5 mg/L

WHO sets 1.5 mg/L as the guideline value for fluoride. Lower concentrations around 0.5 to 1 mg/L protect against dental caries, while chronic intake of higher levels causes fluorosis.

Option by option

  • A. 0.1 mg/L

    0.1 mg/L is too low to be a limit.

  • B. 10 mg/L

    10 mg/L is far above the limit.

  • C. 1.5 mg/L (correct)

    Correct. 1.5 mg/L is the guideline limit.

  • D. 5 mg/L

    5 mg/L is well above the guideline and causes crippling fluorosis.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is C, 1.5 mg/L. WHO sets 1.

Why is "0.1 mg/L" not the answer?

0.1 mg/L is too low to be a limit.

Why is "10 mg/L" not the answer?

10 mg/L is far above the limit.

Why is "5 mg/L" not the answer?

5 mg/L is well above the guideline and causes crippling fluorosis.

What concept does this question test?

It tests Non-communicable diseases: fluoride in drinking water in PSM. 5 mg/L as the guideline value for fluoride. Lower concentrations around 0.5 to 1 mg/L protect against dental caries, while chronic intake of higher levels causes fluorosis.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Non-communicable diseases: fluoride in drinking water?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.