Association of Arsenic Methylation Capacity with Developmental Delays and Health Status in Children: A Prospective Case–Control Trial

This case–control study identified the association between the arsenic methylation capacity and developmental delays and explored the association of this capacity with the health status of children. We recruited 120 children with developmental delays and 120 age- and sex-matched children without developmental delays. The health status of the children was assessed using the Pediatric Quality of Life Inventory (PedsQL) and Pediatric Outcomes Data Collection Instrument (PODCI). The arsenic methylation capacity was determined by the percentages of inorganic arsenic (InAs%), monomethylarsonic acid (MMA(V)%), and dimethylarsinic acid (DMA(V)%) through liquid chromatography and hydride generation atomic absorption spectrometry. Developmental delays were significantly positively associated with the total urinary arsenic concentration, InAs%, and MMA(V)%, and was significantly negatively associated with DMA(V)% in a dose-dependent manner. MMA(V)% was negatively associated with the health-related quality of life (HRQOL; −1.19 to −1.46, P < 0.01) and functional performance (−0.82 to −1.14, P < 0.01), whereas DMA(V)% was positively associated with HRQOL (0.33–0.35, P < 0.05) and functional performance (0.21–0.39, P < 0.01–0.05) in all children and in those with developmental delays. The arsenic methylation capacity is dose-dependently associated with developmental delays and with the health status of children, particularly those with developmental delays.