Fluorosis in endemic areas of Rajasthan is caused by ingestion of groundwater containing fluoride exceeding __ mg/L, and the earliest clinical manifestation is:

• A >1.0 mg/L; dental mottling of permanent teeth
• B >1.5 mg/L; dental fluorosis of permanent teeth in children ✓
• C >3.0 mg/L; skeletal fluorosis with osteosclerosis
• D >5.0 mg/L; crippling skeletal fluorosis with spinal cord compression

Explanation

The WHO permissible limit for fluoride in drinking water is 1.5 mg/L (India's standard is also 1.5 mg/L). Dental fluorosis (mottling) occurs when children are exposed to >1.5 mg/L during tooth formation (up to 8 years of age) and is the earliest and most sensitive indicator of endemic fluorosis. Skeletal fluorosis (osteosclerosis) requires higher and more prolonged exposure (typically >3.0 mg/L for several years). Crippling skeletal fluorosis with neurological compression occurs with very high exposures. Option A (>1.0 mg/L) is below the WHO threshold and would be incorrect.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.