Effect of fluoride exposure on Intelligence Quotient (IQ) among 13-15 year old school children of known endemic area of fluorosis, Nalgonda District, Andhra Pradesh

Background: Waning controversy over fluoride and water fluoridation is rekindling with the findings released from certain fluoride studies which reported an inverse association between fluoride exposure and intelligence. Objective: To assess the relationship between exposure to different drinking water fluoride levels and children's Intelligence Quotient (IQ) among 13-15 year old school children of Nalgonda District, Andhra Pradesh. Methodology: An analytical cross sectional study was conducted among the permanent residents of Na\gonda District of Andhra Pradesh. A total of 1000 school childr~n aged 13-15 years were selected by stratified random sampling from four different areas with different levels of naturally occurring fluoride in drinking water. Raven's standard progressive matrices (1992 Edition) were used for assessment of Intelligence Quotient (IQ) of children. Results: Intellectually superior (Grade I) scores for individual IQ assessment were absent in all the 4 different fluoride levels. Only 0.8% of children were present in Grade l(definitely above the average in intellectual capacity) scores except in 4th level (>4.1ppm). Number of intellectually impaired children were gradually increased with the increase in fluoride concentration in the drinking water. Conclusion: Findings of this study suggest that overall IQ levels in children's exposed to high fluoride level were significantly lower than the low fluoride areas. In view of many endemic Fluorosis areas in India, it is needed that further studies be conducted to examine the link in humans between fluoride & disturbances of the development & function of the central nervous system.