Developmental Fluoride Neurotoxicity: Choi et al. Respond
Anna L. Choi1, Philippe Grandjean1, Guifan Sun2, Ying Zhang2
1Harvard School of Public Health, Boston, Massachusetts, E-mail: email@example.com; 2China Medical University, Shenyang, China
Environ Health Perspect 121:a70–a70 (2013). http://dx.doi.org/10.1289/ehp.1206192R [Online 1 March 2013]
The author declares they have no actual or potential competing financial interests.
Sabour and Ghorbani’s comments about the reported mean difference in IQ (intelligence quotient) scores reported in our article (Choi et al. 2012) suggest a misunderstanding of the scale unit we used and the public health significance of even a small decrease in the average IQ associated with exposure. We appreciate this opportunity to clarify the factual information about the reported IQ measure.
The standardized weighted mean difference (SMD) in IQ score between exposed and reference populations was –0.45 (95% confidence interval: –0.56, –0.35) using a random-effects model (Choi et al. 2012). We used the SMD because the studies we included used different scales to measure the general intelligence. The SMD is a weighted mean difference standardized across studies, giving the average difference in standard deviations for the measure of that outcome. For commonly used IQ scores with a mean of 100 and an SD of 15, 0.45 SDs is equivalent to 6.75 points (rounded to 7 points). As research on other neurotoxicants has shown, a shift to the left of IQ distributions in a population will have substantial impacts, especially among those in the high and low ranges of the IQ distribution (Bellinger 2007).
Bellinger BC. 2007. Interpretation of small effect sizes in occupational and environmental neurotoxicity: individual versus population risk. Neurotoxicology 28:245–251.
Choi AL, Sun G, Zhang Y, Grandjean P. 2012. Developmental fluoride neurotoxicity: a systematic review and meta-analysis. Environ Health Perspect 120:1362–1368.
CEHN July 2015 Article of the Month
“In Utero and Childhood Polybrominated Diphenyl Ether Exposures and Body Mass at Age 7 Years: The CHAMACOS Study” (DOI:10.1289/ehp.1408417) has been selected by the Children’s Environmental Health Network (CEHN) as its July 2015 Article of the Month. These CEHN summaries discuss the potential policy implications of current children’s environmental health research.
2014 Impact Factor
EHP is pleased to announce its new impact factor of 7.98, up from 7.03 last year. EHP is now ranked 2nd of 87 journals in Toxicology, 3rd of 162 journals in Public, Environmental and Occupational Health, and 4th of 221 journals in Environmental Sciences. We thank our authors and readers for their contributions and support.
Sign Up to Receive E-mail Alerts
Recent Advance Publications
Multiple Trigger Points for Quantifying Heat-Health Impacts: New Evidence from a Hot Climate
Environmental Chemicals in Urine and Blood: Improving Methods for Creatinine and Lipid Adjustment
Satellite-Based Spatiotemporal Trends in PM2.5 Concentrations: China, 2004–2013
Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM10 Concentrations and Short-Term Associations with Mortality and Hospital Admissions
Exposure to Bisphenol A and Phthalates during Pregnancy and Ultrasound Measures of Fetal Growth in the INMA-Sabadell Cohort