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Your Environment. Your Health.

Two Insecticides Associated with Reduced Motor Skills in Infants

John Meeker, Ph.D.
University of Michigan
R01ES021465

A study, funded in part by the NIEHS, has linked the insecticides naled and chlorpyrifos to reduced motor skills in babies. This work is one of the first non-occupational studies on the potential health effects of naled, which is being sprayed in the U.S. to combat the mosquito that transmits the Zika virus.

The researchers examined the umbilical cord blood of approximately 240 mothers in China, looking for exposure to 30 different insecticides, five of which showed up in at least 10 percent of the samples. At 6 weeks and 9 months, they tested the motor skills of the babies using the Peabody Developmental Motor Skill Assessment.

At 9 months, infants in the top 25 percent of naled exposure, compared with those in the lowest 25 percent of exposure, exhibited 3 to 4 percent lower fine motor skills, or the small movements of hands, fingers, face, mouth, and feet. Infants exposed to chlorpyrifos scored 2 to7 percent lower on a range of key motor skills, including large movements of arms and legs and fine motor skills. Girls appeared to be more sensitive to the negative effects of the insecticides than boys. The scientists did not identify significant deficits at 6 weeks.

The researchers said that motor delays in infancy may lead to developmental and cognitive problems later in childhood, and that the new results warrant further exploration of the effects of commonly used insecticides on motor development.

Citation: Silver MK, Shao J, Zhu B, Chen M, Xia Y, Kaciroti N, Lozoff B, Meeker JD. 2017. Prenatal naled and chlorpyrifos exposure is associated with deficits in infant motor function in a cohort of Chinese infants. Environ Int 106:248-256.