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Otto Wong

Publications and source records attributed to Otto Wong.

13 recordsLinked to original sources
PubMed2006

Benzene exposure in the shoemaking industry in China, a literature survey, 1978-2004.

This article presents a summary of benzene exposure levels in the shoemaking industry in China reported in the Chinese medical literature between 1978 and 2004. A comprehensive search identified 182 papers reporting such exposure data. These papers could be classified into two categories: benzene poisoning case reports and industrial hygiene surveys. From each paper, the following information was abstracted whenever available: location and year of occurrence, occupation and/or task involved, benzene content in adhesives/solvents, work environment, working conditions, working hours, diagnosis, and air monitoring data of benzene. A total of 333 benzene measurements (88 averages, 116 minimums, 129 maximums) in the shoemaking industry were reported in the 182 papers identified. The data were analyzed in terms of geographical location, time period, type of ownership (state, township, or foreign), type of report (benzene poisoning reports vs. industrial hygiene surveys), and job title (work activity) or process. The reported data covered a wide range; some measurements were in excess of 4500 mg/m(3). Thirty-five percent of the reported benzene concentrations were below 40 mg/m(3), which was the national occupational exposure limit (OEL) for benzene between 1979 and 2001. The remaining 65% measurements, which exceeded the national OEL in effect at the time, and were distributed as follows: 40-100 mg/m(3), 11%; 100-300 mg/m(3), 21%; 300-500 mg/m(3), 13%; and 500+ mg/m(3), 20%. However, only 24% of the reported measurements after 2002 were below 6 mg/m(3), i.e., Permissible Concentration-Time Weighted Average (PC-TWA) and 10 mg/m(3), i.e., Permissible Concentration-Short Term Exposure Limit (PC-STEL), the newly amended benzene OELs in effect after May 2002. The data demonstrated that the majority of the facilities in the shoemaking industry reported in the literature were not in compliance of the OEL for benzene in effect at the time. Overall, the data show a clear downward trend of benzene exposure levels over the years, particularly after the introduction of the new lower OEL in 2002. Even though substantially lower when compared to levels in the past, current benzene exposure measurements from the literature review suggest that many facilities in the shoemaking industry in China have benzene concentrations that are still above the new OEL. The reported data, stratified by job, year and survey reason, can be used as part of the information and analysis for developing a job-exposure matrix in retrospective exposure assessment and thus may be part of the information used in developing historical exposure estimates in epidemiologic studies of shoe workers.

Air Pollutants, Occupational↗
PubMed2006

Lead exposure, lead poisoning, and lead regulatory standards in China, 1990-2005.

This article presents a summary of lead exposure levels and lead poisoning at workplaces in China reported in the Chinese medical literature between 1990 and 2005. A comprehensive literature search identified 618 papers reporting lead exposure and lead poisoning data. The data were analyzed in terms of time period, type of industry, size of factory, and task or process. In 2002 the new Occupational Diseases Prevention and Control Act was passed in China, with new provisions specifically for regulatory enforcement. Therefore, a comparison of lead exposure levels and lead poisoning rates before and after the 2002 Act will shed some light on the effectiveness of the new regulation. The reported lead exposure levels covered a wide range; some measurements were in excess of 250 mg/m(3), which was orders-of-magnitude higher than the occupational exposure levels (OELs) for lead in China. The overall arithmetic mean, median, and geometric mean were 0.92, 0.25, and 0.24 mg/m(3), respectively. Approximately 53.7% of the averages reported in the papers were above the national OELs. The data demonstrated that many facilities in the lead industries reported in the literature were not in compliance with the OELs. Similarly, there appeared to be only a minor impact of the 2002 Act on the reduction of occupational lead poisoning in China. The lead poisoning rates reported in the literature were well above 30%. Judging by the lead exposure levels and the lead poisoning rates, the current overall occupational health monitoring system appears inadequate, lacking the necessary enforcement. The 2002 Act, without the necessary enforcement, did not appear to have a major impact on either lead exposures or lead poisoning in China. Much work in enforcing the 2002 Act remains to be done.

China↗
PubMed2006

The development and regulation of occupational exposure limits in China.

Of the 700 million workers in China, approximately 200 million workers are potentially exposed to industrial hazards. Although the promulgation and implementation of occupational exposure limits (OELs) in China began in the mid-1950, a systematic approach was not formalized until the formation of the Subcommittee of Occupational Health Standards Setting (SOHSS) in 1981. More recently, the 2002 Occupational Disease Prevention and Control Act of the People's Republic of China created the legislative framework for the development and enforcement of OELs. The SOHSS, whose members are primarily health professionals, is the organization responsible for the development of recommended standards, under the auspices of the Ministry of Health. The philosophy of OEL development of the SOHSS consists of a two-step approach: (1) an initial health-based recommended standard is established based on scientific data, and (2) a final law-based standard takes into consideration both socioeconomic and technological feasibility. Governmental agencies such as the Centers for Diseases Control and Prevention and the Institutes of Public Health Supervision at the state, provincial or municipal levels are charged with the responsibilities of the enforcement of OELs. The process and challenges in the enforcement of OELs are discussed. A comparison is made between selected Chinese OELs and those in other countries. The OELs for benzene and industrial dusts (including silica) are discussed in some detail.

Carcinogens, Environmental↗
PubMed2006

The interpretation of occupational epidemiologic data in regulation and litigation: studies of auto mechanics and petroleum workers.

Epidemiologic data often serve as scientific basis for policies in regulation and opinions in litigation. The interpretation of epidemiologic data in both regulation and litigation is often challenged and debated. In this commentary, a wide range of issues concerning the interpretation of epidemiologic data in regulation and litigation are discussed. These issues include: case reports, study design, specificity of exposure, interview or recall bias, misclassification of occupation or exposure, confounding multiple exposures, confidence intervals and statistical power, selection of relevant studies, consistency of study results, study cohort definition, cohort membership misclassification, dilution effect, and subcohort or stratified analysis. Epidemiologic studies of auto mechanics and petroleum workers are used as examples to illustrate the importance of relying on sound epidemiologic principles in study interpretation. If these principles are not followed, the interpretation of epidemiologic studies will likely be erroneous and not useful to regulatory policy-makers or to those involved in litigation.

Automobiles↗
PubMed2005

An overview of published benzene exposure data by industry in China, 1960-2003.

This article presents an overview of occupational benzene exposures in China based on data published in Chinese medical journals. The data were derived from 384 reports of benzene poisoning or industrial hygiene surveys published in Chinese medical journals between 1960 and 2003. The following information was extracted whenever available: industry, occupation, task, date, benzene levels, sampling location, workplace descriptions and, for case reports, medical diagnosis. Each paper provided one or more sets of benzene data, each set representing a sampling location or job title with one to several measurements including, mainly, breathing zone area concentration measurements, and much less frequently personal monitoring. Two criteria based on data quality were applied to select suitable data for analyses. The selected exposure data were analyzed by industry and time period. Nine hundred five sets of benzene measurements from 72 industries were reported in the 384 papers selected for this review, and 621 sets (68.6%) presented average benzene concentrations, which covered 55 industries. The distribution of the reported average benzene exposures was skewed with a median of 51.5 mg/m3. The average benzene concentrations were below 100 mg/m3 for 406 (65%) of the 621 reported average concentrations. The medians of the reported averages in mg/m3 for the five industries with the highest exposures were: 124.8 for leather products, 98.7 for electronic devices, 75.4 for machinery, 50.4 for shoes, and 50.3 for office supplies and sports equipment manufacturing. These data describe the concentrations and changing patterns of occupational benzene exposure by industry and time period in China.

Air Pollutants, Occupational↗
PubMed2005

Exposure to benzene and non-Hodgkin lymphoma, an epidemiologic overview and an ongoing case-control study in Shanghai.

The interest in the relationship between benzene exposure and non-Hodgkin lymphoma (NHL) appears to have been generated from a 1979 publication, which reported an increased risk of NHL among persons potentially exposed to benzene and/or coal tar fractions. More recently (1997), an increased risk of NHL was reported among 74,828 workers exposed to benzene and other chemicals in a variety of industries in China. On the contrary, no increased risk of NHL was reported in a cohort of 1,165 workers at two rubber hydrochloride plants in Ohio (US), who were exposed to extremely high levels of benzene and were found to have an increased risk of acute myeloid leukemia. In another large cohort of some 7,676 US workers exposed to benzene, no increased risk of NHL was reported. Similarly, no increased risk of NHL was reported in a combined cohort of 308,199 petroleum workers in the US, the UK, Canada, Australia, Italy and Finland, who were exposed to benzene or benzene-containing petroleum products. The lack of an association between benzene exposure and NHL in cohort studies is supported by case-control studies from the US, Canada, Italy and the UK. To further investigate the relationship between benzene exposure and NHL, we are conducting a hospital-based case-control study in Shanghai, China. Cases are newly diagnosed NHL patients at 29 hospitals in Shanghai. For each case, two matched controls are selected among patients without any lymphatic or hematopoietic diseases at the same hospital. Demographic, employment, medical and lifestyle information is obtained through questionnaires (primary and secondary). Sources for benzene exposure information include a database of 50,000+ benzene measurements maintained by the Shanghai Municipal Institute of Public Health Supervision (IPHS), Shanghai District IPHS, walk-through surveys at factories, additional measurements at factories and reports in Chinese medical journals. Patient enrollment started in 2003 and it is estimated that the study will have 400-450 NHL cases by December 2006. Some of the occupations or industries reported among enrolled study subjects (cases and controls) with potential exposure to benzene include shoe workers, painters, mechanics or machinists, and printers. Some of the unique features of the study are discussed.

Adolescent↗
PubMed2005

Retrospective cohort mortality study and nested case-control study of workers exposed to creosote at 11 wood-treating plants in the United States.

OBJECTIVE: The objective of this study was to assess both malignant and nonmalignant mortality risks of workers exposed to creosote. For background, a literature review is also presented. MATERIALS AND METHODS: The retrospective cohort study consisted of 2179 employees at 11 plants in the United States where wood (primarily railroad ties and utility poles) is treated with creosote-based preservatives. The observation period covered 1979-2001. Mortality data in the cohort study were analyzed in terms of cause-specific standardized mortality ratios (SMRs) and 95% confidence intervals (95% CIs), with expected deaths based on U.S. national cause-, gender-, race-, year-, age-specific mortality rates. In addition to the cohort investigation, a nested case-control study of lung cancer and multiple myeloma was conducted. Information on tobacco consumption and detailed employment (job titles) was obtained for cases and matched controls. Jobs were classified into 5 categories according to potential for exposure to creosote. Odds ratios (ORs) and 95% CIs were calculated for job categories and length of exposure. RESULTS: Overall mortality for the entire cohort was lower than expected (293 observed deaths vs. 325.37 expected, SMR = 90.1, 95% CI = 80.0-101.0). Close to 90% employees were hourly, whose potential for exposure was generally much higher than that of salaried employees. Among hourly employees, except for multiple myeloma, none of the specific cancer sites showed any significant increase. Furthermore, detailed analysis by length of employment did not reveal any significant mortality excess or upward trend. Six deaths were from multiple myeloma, whereas 1.50 deaths were expected (SMR = 401.1, 95% CI = 147.2-873.1). However, analysis by length of employment did not show any upward trend for multiple myeloma. No significant mortality increase was reported for any nonmalignant disease, and analysis by length of employment did not reveal any upward trend. In the case-control study, an increased risk of lung cancer was associated with tobacco consumption (OR = 4.92) but not with any job/exposure category. For example, the lung cancer odds ratio for routine exposure to creosote-based wood preservatives was 0.58 (95% CI = 0.11-3.03). Similarly, case-control analyses of multiple myeloma did not reveal any association with employment at the plants or with exposure to creosote-based wood preservatives or to creosote-treated products. CONCLUSION: Based on the present investigation and other studies, there was no evidence that employment at the 11 wood-treating plants or exposure to creosote-based wood preservatives was associated with any significant mortality increase from site-specific cancers or nonmalignant diseases. Some results should be interpreted with caution because they were based on small numbers.

Adult↗
PubMed2004

Carcinogenicity of trichloroethylene: an epidemiologic assessment.

Trichloroethylene (TCE) is used extensively in various industries. Because of its solubility in water, TCE also is often found in contaminated groundwater and drinking water. TCE is not only an occupational health issue but also a public health concern. This article focuses on the scientific literature of TCE and cancer. Included in this article are epidemiologic studies from the United States and Europe of TCE manufacturing workers, metal polishers and platers, aerospace manufacturing and maintenance workers, and jewelry workers who used TCE. Also included are several recent studies from Taiwan, consisting of electronics factory workers who used TCE and nearby community residents who consumed TCE-contaminated groundwater.

Humans↗
PubMed2003

Regulation of occupational exposures in China.

The recent passage of the Occupational Diseases Prevention and Control Act of 2002 (ODPCAct) in China and the new occupational exposure limits signify the Chinese government's commitment to improve the environment of the workplace and to eradicate preventable occupational diseases. The effectiveness of the ODPCAct, however, will depend on not only implementation and enforcement but also education and communication. For large industrial facilities, implementation of the new regulations can be enforced with periodic monitoring and inspections. The difficulty will come from small makeshift or crudely converted workshops in villages and small towns in rural areas. The challenge will be to reach out to these small workshop owners and workers, i.e., to communicate and inform them about the newly promulgated regulations, the business owners' legal responsibility and liability, and the workers' right to a safe workplace. Attention and resources should be focused on educating both shop owners and workers about the hazards of the chemicals that they use, basic requirements for a safe workplace, preventive measures, and controls to reduce exposures.

China↗
PubMed2003

Is there a causal relationship between exposure to diesel exhaust and multiple myeloma?

This article presents a comprehensive critical review of the epidemiology of multiple myeloma in relation to occupational diesel exhaust exposure. The review includes cohort and proportional mortality studies of workers exposed to diesel exhaust, and population-based case-control studies of multiple myeloma. None of the cohort or proportional mortality studies reported a significant increase of multiple myeloma in relation to diesel exhaust, with the exception of a study of Danish truck drivers. Several limitations in this Danish study (such as inadequate cohort identification, small number of multiple myeloma deaths and inappropriate analytical method) made the result unreliable. Furthermore, the data in this study of Danish truck drivers were part of and, hence, superseded by a large study in Denmark, which did not find any increased risk of multiple myeloma. Similarly, none of the case-control studies reported a significant increase of multiple myeloma in relation to diesel exhaust, with the exception of the smallest case-control study based on multiple myeloma patients in central and southeast Sweden. The result of this small Swedish study was not reliable because of incomplete case ascertainment, inappropriate controls and confounding. Furthermore, the data in this small Swedish study were part of and, hence, superseded by a large national study of workers exposed to diesel exhaust in Sweden, which did not find any increased risk of multiple myeloma. Other than the study of Danish truck drivers and the small case-control study of multiple myeloma patients in central and southeast Sweden, all other epidemiological investigations consistently reported no increase of multiple myeloma in relation to occupational diesel exhaust exposure. Furthermore, none of the studies reported a positive exposure-response relationship between diesel exhaust and multiple myeloma. Several studies that analysed data by jobs or occupations according to level of exposure and by duration of exposure did not find any upward trend. In addition to the review, a formal causation analysis based on an application of the Hill criteria confirms that there is no causal relationship between diesel exhaust and multiple myeloma.

Denmark↗