OBJECTIVES: To evaluate effects of lead on the central nervous system of children by measuring blood lead concentration, computerized neurobehavioral function and intelligence of elementary school students. METHODS: The study was conducted with 208 elementary school students living in the vicinity of Pohang Industrial Complex in October and November, 2005. Data on demographic characteristics, living environments and lifestyle habits were collected from subjects. RESULTS: Blood lead levels of elementary school students ranged from 0.76-4.97 microg/dl, which is below the 10 microg/dl recommended level of CDC. The blood lead levels were similar with those reported in other domestic and international studies. Neurobehavioral tests revealed that most third grade students reacted slowly and their speed declined in simple reaction time (p<0.05), choice reaction time (p<0.05), symbol digit substitution (p<0.01), finger tapping speed nondominant hand (p<0.05) as blood lead levels increased. Sixth grade students demonstrated significance in test performance, and displayed blood lead levels of 2.00-4.00 microg/dl. Results of intelligence testing showed significantly low performance in IQ (p<0.05), vocabulary ability (p<0.05), reasoning ability (p<0.05), mathematical ability (p<0.05) and perception ability (p<0.05) among third grade students who displayed high levels of blood lead concentration. Sixth grade students showed significantly low performance in vocabulary ability (p<0.05) at high level of blood lead concentration. The difference in mean IQ scores between the group with blood lead level of < or =2.00 microg/dl and the group with blood lead level > or =3.00 microg/ dl was 3.21 in third grade students and 4.28 in sixth grade students. Low academic achievement was observed among third grade students (p<0.05) and six grade students (p<0.05) as the average blood lead level increased. Correlation analysis on the association of blood lead concentration with neurobehavioral tests revealed a positive correlation between blood lead levels and reaction time of choice reaction time and symbol digit substitution in third grade students. A positive correlation was observed between blood lead levels and reaction time of symbol digit substitution and finger tapping speed in sixth grade students. There was a negative correlation between blood lead levels and reasoning ability of third grade students (r=-0.247) and vocabulary ability of six grade students (r=-0.255). CONCLUSION: There have been few studies on the effects of blood lead on the central nervous systems of children in Korea. The study supports the findings of earlier studies that blood lead has an impact on children. However, the study did not confirm significant association of blood lead concentration with each neurological and motor test conducted for this study due to a small sample size and relatively low blood lead levels of elementary school students. Further studies using a similar assessment methods would be helpful to evaluate the effects of low blood lead levels on the central nervous systems of children.
Achievement ; Centers for Disease Control and Prevention (U.S.) ; Central Nervous System ; Child ; Fingers ; Hand ; Humans ; Intelligence ; Intelligence Tests ; Korea ; Life Style ; Perception ; Reaction Time ; Sample Size ; Vocabulary

OBJECTIVES: To evaluate effects of lead on the central nervous system of children by measuring blood lead concentration, computerized neurobehavioral function and intelligence of elementary school students. METHODS: The study was conducted with 208 elementary school students living in the vicinity of Pohang Industrial Complex in October and November, 2005. Data on demographic characteristics, living environments and lifestyle habits were collected from subjects. RESULTS: Blood lead levels of elementary school students ranged from 0.76-4.97 microg/dl, which is below the 10 microg/dl recommended level of CDC. The blood lead levels were similar with those reported in other domestic and international studies. Neurobehavioral tests revealed that most third grade students reacted slowly and their speed declined in simple reaction time (p<0.05), choice reaction time (p<0.05), symbol digit substitution (p<0.01), finger tapping speed nondominant hand (p<0.05) as blood lead levels increased. Sixth grade students demonstrated significance in test performance, and displayed blood lead levels of 2.00-4.00 microg/dl. Results of intelligence testing showed significantly low performance in IQ (p<0.05), vocabulary ability (p<0.05), reasoning ability (p<0.05), mathematical ability (p<0.05) and perception ability (p<0.05) among third grade students who displayed high levels of blood lead concentration. Sixth grade students showed significantly low performance in vocabulary ability (p<0.05) at high level of blood lead concentration. The difference in mean IQ scores between the group with blood lead level of < or =2.00 microg/dl and the group with blood lead level > or =3.00 microg/ dl was 3.21 in third grade students and 4.28 in sixth grade students. Low academic achievement was observed among third grade students (p<0.05) and six grade students (p<0.05) as the average blood lead level increased. Correlation analysis on the association of blood lead concentration with neurobehavioral tests revealed a positive correlation between blood lead levels and reaction time of choice reaction time and symbol digit substitution in third grade students. A positive correlation was observed between blood lead levels and reaction time of symbol digit substitution and finger tapping speed in sixth grade students. There was a negative correlation between blood lead levels and reasoning ability of third grade students (r=-0.247) and vocabulary ability of six grade students (r=-0.255). CONCLUSION: There have been few studies on the effects of blood lead on the central nervous systems of children in Korea. The study supports the findings of earlier studies that blood lead has an impact on children. However, the study did not confirm significant association of blood lead concentration with each neurological and motor test conducted for this study due to a small sample size and relatively low blood lead levels of elementary school students. Further studies using a similar assessment methods would be helpful to evaluate the effects of low blood lead levels on the central nervous systems of children.
Achievement ; Centers for Disease Control and Prevention (U.S.) ; Central Nervous System ; Child ; Fingers ; Hand ; Humans ; Intelligence ; Intelligence Tests ; Korea ; Life Style ; Perception ; Reaction Time ; Sample Size ; Vocabulary

OBJECTIVES: This study was conducted to assess the concentration of urine cadmium and health risks of residents in the vicinity of abandoned metal mines in Gyeongsangbuk-do. METHODS: The concentration of cadmium in the soil, water, and agricultural crops was measured in Gyeongsangbuk-do, Butdeun and Suksan, which have abandoned metal mines. We measured the concentration of cadmium in the urine of residents from the following areas: 78 from village A, 99 from village C and 147 from control areas. Other health-risk assessments were performed on each resident, such as measuring the concentration of beta2-MG and a bone density test. RESULTS: In abandoned mine areas, the mean concentration of cadmium was higher in agricultural soil and in the crops than in that of control areas. The concentration of cadmium in the stream exceeded the guideline level. In regard to provisional tolerable daily intake (PTDI) of cadmium, the actual intake rate through crops was 33.81%, 72.74% in abandoned mine areas and 5.03%, 6.16% in control areas. Residents in abandoned mine areas, A village and C village had a geometric mean of urine Cd of 1.90 microgram/g cr and 1.45 microgram/g cr. These measurements were significantly higher than those of residents in control areas, B village and D village, 0.59 microgram/g cr and 0.65 microgram/g cr (p<0.01). Following adjustments for age, sex, smoking habit, and occupational history, the concentration of urine cadmium of residents in the Butdeun abandoned meta mine was higher by 1.62 microgram/g cr as compared with the control group (p<0.01). Residents from the Suksan abandoned metal mine also had a higher concentration by 1.07 microgram/g cr (p<0.01). A multiple linear regression analysis was performed for the factors associated with T-score, and this showed that the concentration of urine cadmium was not an influential factor. CONCLUSIONS: Based on these measurements, areas with abandoned metal mines contaminated streams, agricultural soil, and crops of the adjacent areas, with cadmium. Because residents in the adjacent areas intake contaminated crops, their urine cadmium was increased. Despite a lack of evidence demonstrating the detrimental effect of increased urine cadmium in residents, an additional study is needed to assess the health risks of residents in the vicinity of abandoned metal mines.
Bone Density ; Cadmium ; Crops, Agricultural ; Korea ; Linear Models ; Rivers ; Smoke ; Smoking ; Soil ; Water