Biomedical subjects

Kun-Yu Chao

Publications and source records attributed to Kun-Yu Chao.

6 recordsLinked to original sources

PubMed2005

Reversible neurobehavioral performance with reductions in blood lead levels--a prospective study on lead workers.

Lead poisoning remains an occupational hazard in Taiwan. Many studies, based on crossed-section design, have focused on changes in lead-associated neurobehavioral dysfunctions that occur at increased blood lead levels. This study evaluates the changes in neurobehavioral performance of lead workers as blood levels are reduced. We tested 27 lead workers in a lead glaze factory using the computer-based and automated Chinese edition of Neurobehavioral Evaluation System 2 (C-NES II) in 1994, 1996, and 1997. The association of blood lead levels and C-NES II results were analyzed by longitudinal data analysis methods, repeated ANOVA and mixed model analyses after adjustment for potential confounders. Over these 4 years, the mean lead blood levels of workers were reduced from 26.3(SD=12.0) to 8.3(SD=6.9) microg/dL. Based on a mixed model analysis, we found that the negative effects of exposure to lead on neurobehavioral performance can be reversed to some extent with lowering levels of blood lead. During this period, we found significant improvements in 3 subtests: finger tapping, pattern comparison reaction time, and memory. This study tentatively concluded that reversibility of the neurobehavioral performance after reduction of the lead exposure, which encourages industrial hygiene and personal health promotion to reduce their body lead burden. However, though use of NES is more sensitive to detect the changes, the chronic symptoms (using standardized questionnaire) were found to decline slowly when blood lead level is reduced, with no statistically significant difference. The result means that to avoid the lead exposure primarily is essential to prevent chronic symptoms. We conclude that the most important way to prevent and possibly reverse chronic symptoms of lead poisoning remains to be the avoidance of exposure to lead.

Adult↗

PubMed2005

Estimation of burden of lead for offspring of female lead workers: a quality-adjusted life year (QALY) assessment.

This study demonstrates an empirical example that uses quality-adjusted life year (QALY) as a common metric for occupational health assessment to measure the utility loss of potential lead-exposed children delivered by female lead-battery-exposed workers. A set of nationwide health examination data was used for 1726 lead workers. Among them, there were 649 female workers. The numbers of offspring from female lead workers were estimated by multiplying the age-specific fertility rate (ASFR) by the number of workers in each age stratum. The quality of life assessment for these offspring was assumed impaired by increased absorption of lead using a measure of utility for quality of life that was adapted from Rosser's index of health-related quality of life. The total utility loss was calculated by summing up the loss of QALY for these expected offspring. Dose-response and exposure assessments were based on their mothers' blood lead levels. It was estimated that more than 38 babies were delivered in 1 yr. There would be 19 babies born with blood lead levels over 30 microg/dl, and about 17 babies with blood lead between 10 and 29 microg/dl. The expected utility loss of the babies was estimated to be about 216 QALY, of which 51.6 QALY was attributed to the babies with moderate blood lead level, while that of high blood lead was 164.4 QALY. An effective industrial hygiene program to reduce blood lead to 5, 10, and 15 microg/dl in female lead-exposed workers would decrease the utility loss to 169.5, 126.8, and 92.3 QALY, respectively, in the offspring. An alternative policy of raising the age of female workers by 5 or 10 yr before employment would also reduce the loss to 174.6 or 107.4 QALY. Data suggest that an effective industrial hygiene program should be implemented, and the use of QALY as a common metric for comparative assessment of occupational health policy may be feasible.

Adult↗

PubMed2004

The influence of milk intake on the lead toxicity to the sensory nervous system in lead workers.

The dietary calcium supplement has been suggested to children and pregnant women for prevention of lead toxicity, because of lead-calcium interaction. Lead workers were supplied free milk in Taiwan; however, part of workers did not drink milk due to lactose intolerance. The goal of this study is to evaluate the effects of milk-intake on the peripheral nervous system in workers with long-term lead exposure. We measured 181 workers' current perception thresholds (CPT) as neurological outcomes. The outcome variables were then correlated to the subject's milk intake, blood lead levels, and index of long-term lead exposure that was calculated by the subject's serial blood lead data in a period of working duration. The potential confounders, including age, gender, body height, smoking and alcohol consumption, were also collected and analyzed in multiple regressions. 23 workers who reported never or rarely drinking milk, which meant that they have suffered from diarrhea or abdomen discomfort after drinking milk since childhood, had higher blood lead parameters but not statistically significant, and higher thresholds in sensory nerve tests, especially, statistically significance on 5 and 250 Hz of hand CPTs, which represent C fiber and A-delta fiber. In multiple regression models with control of potential confounders, significant protective effects of milk intake were found on reducing hand CPTs, but not on foot CPTs. Our study, using measurement of sensory nerve CPTs, revealed that drinking milk (two bottles a day, about 700 g per day) might have an effect to protect lead peripheral neurotoxicity. The detail biochemical mechanisms need further investigations. However, reduction of occupational lead exposure is the essential way to protect lead neuropathy. The authors did not emphasize that offers of milk to workers could be instead of occupational hygiene efforts. Furthermore, lead workers with lactose intolerance might be more susceptible, and need more industrial hygiene interventions.

Adult↗

PubMed2002

Using structural equation model to explore occupational lead exposure pathways.

The aim of the present study was to demonstrate the use of a structural equation model to explore the complicated lead exposure pathways in a lead battery plant. A total of 96 out of 113 assembly workers were recruited in this study. Lead measurements included blood lead, respirable airborne lead, and body surface lead loadings. Latent variables of inadvertent contact of lead on fingers and ingested lead had indirect and direct effects on the blood lead levels, respectively, and so did the variables of respirable airborne lead, smoking, and the working-place clothes being washed. A model chi(22)2 value of 31.1 (P=0.094) for a goodness of fit test indicates that the derived structural equation model appropriately accounted for the variation of blood lead levels. It is concluded that lead loadings on fingers and lips had significant effects on occupational lead uptake, and, after-work hours and break times at work were the critical time periods for inadvertent lead exposure.

Activities of Daily Living↗

PubMed2002

The distribution of blood lead levels and job titles among lead-acid battery workers in Taiwan.

There were several reports about elevated blood lead levels in lead battery workers. However, their subjects came from only one or several plants. We visited all the 23 registered lead-acid battery plants in Taiwan and collected their health examination records in 1992, the blood lead analyses of which were completed in 3 medical college hospitals. In total, we have obtained 1726 records. The average blood lead concentration was 37.1 ug/dl, and 37% of blood lead levels were more than 40 ug/dl (action level). The overall participation rate for health examination among employees was 69.4%. The participation rates were different among both plant sizes and job titles. Assuming that there was no peculiar variation within the four working zones (plate manufacture jobs, assembly jobs, part-time exposure jobs, and office jobs) in each plant, and that blood lead levels of our samples were stable after deleting newly hired workers, we estimated that the blood lead distributions of 2486 employees in these plants were 63.3%, 26.4%, 9.25% and 1.05% for below 40, 40-59, 60-79, and above 80 ug/dl respectively. We conclude that such an analysis should be performed each year to monitor the effectiveness of occupational hygiene in workplace of lead battery plants.

Humans↗

PubMedDate not supplied

Percutaneous absorption of inorganic lead compounds.

The objective of this study was to determine percutaneous absorption of lead compounds, including lead sulfate, lead oxide, lead powder, and lead stearate. The lead content on the skin surface of 10 lead-battery workers was measured by the method of skin stripping, and urinary lead content of rats was measured with epicutaneous application of four lead compounds: lead sulfate, lead oxide, lead powder, and lead stearate. There were significant amounts of lead on the 9th and 10th skin strippings of the dorsal hand and the back of lead workers. The amount of lead on the dorsal hand was significantly correlated with the amount in the blood (n = 10, r 2 = 0.66, p < 0.05, linear regression). In rats, after lead compounds were applied for 12 days, total lead amount in urine significantly increased to 146.0 +/- 6.4 ng (SD) for lead stearate, 123.1 +/- 7.2 ng for lead sulfate, 115.9 +/- 5.3 ng for lead oxide, 47.8 +/- 6.9 ng for lead powder, and 10.3 ng for the control, which indicated significant skin absorption. It was concluded that significant amounts of inorganic lead compounds can be absorbed through the skin, and skin protection in lead-working or any contaminated environment should be carefully considered.

Animals↗