Association between chronic exposure to arsenic and slow nerve conduction velocity among adolescents in Taiwan.

The association between chronic exposure to arsenic and peripheral neuropathy has been controversial in previous studies, which may be due to the influence of factors, such as age, gender, chronic diseases, occupational injuries, and arsenic exposure. To clarify the question of this association, a cross-sectional study was designed. In total, 130 junior high school students aged 12-14 years were included and examined for the motor and sensory nerve conduction velocity of peripheral nerves in their right-upper and lower limbs. Concentrations of arsenic in well-water and history of drinking well-water were retrieved from a baseline database created in 1991. After adjustment for gender and height, a significant odds ratio of 2.9 (95% confidence interval [CI] 1.1-7.5) was observed for the development of slow nerve conduction velocity of the sural sensory action potential (SAP) among the study subjects with a cumulative arsenic dosage of>100.0 mg. In addition, a borderline statistical significance with odds ratio of 7.8 (95% CI 1.001-69.5) for the development of slow nerve conduction velocity of sural SAP was also observed among the study subjects who drank well-water containing arsenic concentrations of >50.0 microg/L and with a cumulative arsenic dosage of >100.0 mg. The study found that chronic exposure to arsenic might induce peripheral neuropathy. It also found that the slowing of the nerve conduction velocity of sural SAP might be an early marker of chronic arsenic neuropathy.

The effects of chronic arsenic exposure from drinking water on the neurobehavioral development in adolescence.

This cross-sectional study examined the possible influence on the development of cognitive function among adolescents due to long-term arsenic exposure. Forty-nine junior school students drinking arsenic-containing well water and 60 controls matched with age, sex, education, body height, body weight, body mass index, and socioeconomic status were compared. The former was divided into two groups: high and low exposure, with mean cumulative arsenic levels of 520629.0+/-605824.2 and 13782.2+/-12886.0 ppm, respectively. Four neurobehavioral tests including continuous performance test (CPT), symbol digit (SD), pattern memory (PM) and switching attention (SA) were applied. A strong correlation between age and education caused collinearity in the multiple regression model (r=0.84, P<0.0001). Only education and sex, excluding age, were entered into the model as covariates. Pattern memory and switching attention were significantly affected by long-term cumulative exposure to arsenic after adjusting for education and sex. It is suggested that the arsenic levels in the well water may be monitored extensively, but if there is no intervention, then neurobehavioral function will not be protected. Limitations of the current study require replication of this effect in other studies to confirm this conclusion.