Biological Trace Element Research

, Volume 126, Issue 1–3, pp 115–120 | Cite as

Fluoride and Children’s Intelligence: A Meta-analysis

  • Qin-qing Tang
  • Jun Du
  • Heng-hui Ma
  • Shao-jun Jiang
  • Xiao-jun ZhouEmail author


This paper presents a systematic review of the literature concerning fluoride that was carried out to investigate whether fluoride exposure increases the risk of low intelligence quotient (IQ) in China over the past 20 years. MEDLINE, SCI, and CNKI search were organized for all documents published, in English and Chinese, between 1988 and 2008 using the following keywords: fluorosis, fluoride, intelligence, and IQ. Further search was undertaken in the website because this is a professional website concerning research on fluoride. Sixteen case–control studies that assessed the development of low IQ in children who had been exposed to fluoride earlier in their life were included in this review. A qualitative review of the studies found a consistent and strong association between the exposure to fluoride and low IQ. The meta-analyses of the case–control studies estimated that the odds ratio of IQ in endemic fluoride areas compared with nonfluoride areas or slight fluoride areas. The summarized weighted mean difference is −4.97 (95%confidence interval [CI] = −5.58 to −4.36; p < 0.01) using a fixed-effect model and −5.03 (95%CI = −6.51 to 3.55; p < 0.01) using a random-effect model, which means that children who live in a fluorosis area have five times higher odds of developing low IQ than those who live in a nonfluorosis area or a slight fluorosis area.


Fluoride Fluorosis Intelligence quotient Meta-analysis 



The authors are grateful to Dr. Gui-lan Tang, College of Resources and Environmental Sciences, China Agricultural University, Beijing, People’s Republic of China, for providing the critical review and assistance during the course of this investigation. The authors also appreciate the editor board and the reviewers for their work on this paper.


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Copyright information

© Humana Press Inc. 2008

Authors and Affiliations

  • Qin-qing Tang
    • 1
  • Jun Du
    • 1
  • Heng-hui Ma
    • 1
  • Shao-jun Jiang
    • 1
  • Xiao-jun Zhou
    • 1
    Email author
  1. 1.Department of PathologyNanjing University School of Medicine, Nanjing Jinling HospitalNanjingPeople’s Republic of China

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