Association between chronic arsenic exposure and children's intelligence in Thailand

Previous studies have reported high arsenic level in hair of children at Ronpiboon subdistrict. It is possible that the accumulation of arsenic in their bodies may adversely affect intelligence. This study aims to explore the relationship between arsenic level in hair and intelligence of children. We measured the arsenic level in hair using atomic absorption spectrophotometry method as the indicator of chronic arsenic exposure and IQ with Wechsler Intelligence Scale Test for Children. Potential confounders were collected at the same time period of this cross-sectional study between 16 January and 5 March, 1995. To explore the association multiple classification analysis was conducted with data from 529 children aged 6-9 years who had lived in Ronpiboon district since birth. This study found an association between arsenic hair levels and children's intelligence. After adjusting for confounders, we observed a statistically significant relationship that arsenic could explain 14% of variance in children's IQ. This result revealed that chronic arsenic exposure as shown by hair samples was related to retardation of intelligence in children. Prevention of further arsenic exposure and health status monitoring of children with arsenic accumulation should be implemented.