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1.  Effects of heat on workers' health and productivity in Taiwan 
Global Health Action  2009;2:10.3402/gha.v2i0.2024.
The impact of global warming on population health is a growing concern and has been widely discussed. The issue of heat stress disorders and consequent productivity reduction among workers has not yet been widely addressed. Taiwan is an island straddling the Tropic of Cancer in the West Pacific and has both subtropical and tropical climates. As of 2008, the economy of Taiwan accounts for 1.1% of the world gross domestic product at purchasing power parity and is listed as 19th in the world and eighth in Asia, according to International Monetary Fund data.
The aim of this paper is to identify occupations at risk and the potential health impacts of heat on workers in Taiwan.
Historical data relating to meteorology, population, the labour force and economy were obtained from publicly available databases from the Taiwanese government.
Hot seasons with an average maximum temperature above 30°C and relative humidity above 74%, lasting for four to six months from May to October, pose health threats to construction, farming and fishery workers. In particular, populations of ageing farmers and physically overloaded construction workers are the two most vulnerable worker categories in which high temperature impacts on health and productivity.
Currently, regulations and preventive actions for heat relief are difficult to enforce for several reasons, including lack of equipment for measuring environmental conditions, lack of awareness of potential hazards and strict time constraints imposed on workers. There is an urgent need to systematically and comprehensively assess the impact of a warming climate on workers’ health and productivity to provide effective prevention strategies for a better working and living environment in Taiwan.
PMCID: PMC2799321  PMID: 20052376
occupational health; global warming; hot temperature; heat stress disorders; productivity
2.  Is the reporting timeliness gap for avian flu and H1N1 outbreaks in global health surveillance systems associated with country transparency? 
This study aims to evaluate the length of time elapsed between reports of the same incidents related to avian flu and H1N1 outbreaks published by the WHO and ProMED-mail, the two major global health surveillance systems, before and after the amendment of the International Health Regulations in 2005 (IHR 2005) and to explore the association between country transparency and this timeliness gap.
We recorded the initial release dates of each report related to avian flu or H1N1 listed on the WHO Disease Outbreak News site and the matching outbreak report from ProMED-mail, a non-governmental program for monitoring emerging diseases, from 2003 to the end of June 2009. The timeliness gap was calculated as the difference in days between the report release dates of the matching outbreaks in the WHO and ProMED-mail systems. Civil liberties scores were collected as indicators of the transparency of each country. The Human Development Index and data indicating the density of physicians and nurses were collected to reflect countries’ development and health workforce statuses. Then, logistic regression was performed to determine the correlation between the timeliness gap and civil liberties, human development, and health workforce status, controlling for year.
The reporting timeliness gap for avian flu and H1N1 outbreaks significantly decreased after 2003. On average, reports were posted 4.09 (SD = 7.99) days earlier by ProMED-mail than by the WHO. Countries with partly free (OR = 5.77) and free civil liberties scores (OR = 10.57) had significantly higher likelihoods of longer timeliness gaps than non-free countries. Similarly, countries with very high human development status had significantly higher likelihoods of longer timeliness gaps than countries with middle or low human development status (OR = 5.30). However, no association between the timeliness gap and health workforce density was found.
The study found that the adoption of IHR 2005, which contributed to countries’ awareness of the importance of timely reporting, had a significant impact in improving the reporting timeliness gap. In addition, the greater the civil liberties in a country (e.g., importance of freedom of the media), the longer the timeliness gap.
PMCID: PMC3615947  PMID: 23531369
3.  Asian forum on environmental health policy: challenges and perspectives of environmental health problems in the region in the next 30 years 
PMCID: PMC3342631  PMID: 22351507
Medicine & Public Health; Occupational Medicine/Industrial Medicine; Environmental Health; Public Health/Gesundheitswesen; Medicine/Public Health, general; Health Promotion and Disease Prevention
4.  Political and social determinants of life expectancy in less developed countries: a longitudinal study 
BMC Public Health  2012;12:85.
This study aimed to examine the longitudinal contributions of four political and socioeconomic factors to the increase in life expectancy in less developed countries (LDCs) between 1970 and 2004.
We collected 35 years of annual data for 119 LDCs on life expectancy at birth and on four key socioeconomic indicators: economy, measured by log10 gross domestic product per capita at purchasing power parity; educational environment, measured by the literacy rate of the adult population aged 15 years and over; nutritional status, measured by the proportion of undernourished people in the population; and political regime, measured by the regime score from the Polity IV database. Using linear mixed models, we analyzed the longitudinal effects of these multiple factors on life expectancy at birth with a lag of 0-10 years, adjusting for both time and regional correlations.
The LDCs' increases in life expectancy over time were associated with all four factors. Political regime had the least influence on increased life expectancy to begin with, but became significant starting in the 3rd year and continued to increase, while the impact of the other socioeconomic factors began strong but continually decreased over time. The combined effects of these four socioeconomic and political determinants contributed 54.74% - 98.16% of the life expectancy gains throughout the lag periods of 0-10 years.
Though the effect of democratic politics on increasing life expectancy was relatively small in the short term when compared to the effects of the other socioeconomic factors, the long-term impact of democracy should not be underestimated.
PMCID: PMC3331806  PMID: 22280469
Life expectancy; Socioeconomic factors; Developing countries; World health; Political factors; Public health; Malnutrition; Literacy; Democracy
5.  Ambient Influenza and Avian Influenza Virus during Dust Storm Days and Background Days 
Environmental Health Perspectives  2010;118(9):1211-1216.
The spread of influenza and highly pathogenic avian influenza (H5N1) presents a significant threat to human health. Avian influenza outbreaks in downwind areas of Asian dust storms (ADS) suggest that viruses might be transported by dust storms.
We developed a technique to measure ambient influenza and avian influenza viruses. We then used this technique to measure concentrations of these viruses on ADS days and background days, and to assess the relationships between ambient influenza and avian influenza viruses, and air pollutants.
A high-volume air sampler was used in parallel with a filter cassette to evaluate spiked samples and unspiked samples. Then, air samples were monitored during ADS seasons using a filter cassette coupled with a real-time quantitative polymerase chain reaction (qPCR) assay. Air samples were monitored during ADS season (1 January to 31 May 2006).
We successfully quantified ambient influenza virus using the filtration/real-time qPCR method during ADS days and background days. To our knowledge, this is the first report describing the concentration of influenza virus in ambient air. In both the spiked and unspiked samples, the concentration of influenza virus sampled using the filter cassette was higher than that using the high-volume sampler. The concentration of ambient influenza A virus was significantly higher during the ADS days than during the background days.
Our data imply the possibility of long-range transport of influenza virus.
PMCID: PMC2944079  PMID: 20435545
ambient virus; avian influenza virus; bioaerosol; dust storm; infectious bioaerosol; influenza virus; quantification; real-time qPCR
6.  Effects of Occupational Noise Exposure on 24-Hour Ambulatory Vascular Properties in Male Workers 
Environmental Health Perspectives  2007;115(11):1660-1664.
Epidemiologic studies have demonstrated that occupational noise exposure is associated with hypertension, but the related mechanism in vascular structural changes is unclear.
This panel study aimed to investigate effects of occupational noise exposure on ambulatory vascular structural properties in male workers.
We recruited 20 volunteers and divided them into a high-noise–exposure group of 15 and a low-noise–exposure group of 5 based on environmental noise measurement in an automobile manufacturing company. We determined individual noise exposure and measured personal ambulatory vascular property parameters simultaneously during 24 hr. Linear mixed-effects regression models were used to estimate transient and sustained effects of noise exposure on vascular parameters by adjusting some confounders collected from self-administrated questionnaires and health checkups.
The high-noise–exposed (85 ± 8 dBA) workers had significantly higher systemic vascular resistance (SVR) than the low-noise–exposed workers (59 ± 4 dBA) during work and sleep periods. Contrarily, low-noise–exposed workers had significantly higher brachial artery compliance (BAC), brachial artery distensibility (BAD), and systemic vascular compliance (SVC; marginal, p = 0.07) than high-noise–exposed workers during off-duty periods. We also found that high-noise–exposed workers had significantly lower BAC (1.38 ± 0.55 %mL/mmHg) and BAD (1.29 ± 0.51 %/mmHg), as well as lower SVC (0.24 ± 0.10 mL/L/mmHg), but higher SVR (1.93 ± 0.67 mL/L/min) compared with low-noise–exposed workers over a 24-hr period.
Our findings suggest that in automobile workers, occupational noise exposure may have sustained, not transient, effects on vascular properties and also enhances the development of hypertension.
PMCID: PMC2072860  PMID: 18008000
ambulatory arterial stiffness; ambulatory vascular properties; automobile workers; occupational noise exposure; panel study
7.  Interaction Effects of Ultrafine Carbon Black with Iron and Nickel on Heart Rate Variability in Spontaneously Hypertensive Rats 
Environmental Health Perspectives  2007;115(7):1012-1017.
Particulate matter (PM) has been reported to be associated with alterations in heart rate variability (HRV); however, the results are inconsistent. We propose that different components of PM cause the discrepancy.
In this study, our goal was to determine whether different types of exposure would cause different HRV effects, and to verify the interactions between co-exposing components.
Ultrafine carbon black (ufCB; 14 nm; 415 μg and 830 μg), ferric sulfate [Fe2(SO4)3; 105 μg and 210 μg], nickel sulfate (NiSO4; 263 μg and 526 μg), and a combination of high-dose ufCB and low-dose Fe2(SO4)3 or NiSO4 were intratracheally instilled into spontaneously hypertensive rats. Radiotelemetry data were collected in rats for 72 hr at baseline and for 72 hr the following week to determine the response to exposure. Effects of exposure on 5-min average of normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN), and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD) were analyzed using self-control experimental designs.
Both high- and low-dose ufCB decreased ANN marginally around hour 30, with concurrent increases of LnSDNN. LnRMSSD returned to baseline levels after small initial increases. We observed minor effects after low-dose Fe and Ni instillation, whereas biphasic changes were noted after high-dose instillations. Combined exposures of ufCB and either Fe or Ni resulted in HRV trends different from values estimated from individual-component effects.
Components in PM may induce different cardioregulatory responses, and a single component may induce different responses during different phases. Concurrent exposure to ufCB and Fe or Ni might introduce interactions on cardioregulatory effects. Also, the effect of PM may be mediated through complex interaction between different components of PM.
PMCID: PMC1913579  PMID: 17637915
ambient particles; heart rate variability; interaction; iron; nickel; spontaneously hypertensive rats; ultrafine carbon black
8.  Grand Rounds: Outbreak of Hematologic Abnormalities in a Community of People Exposed to Leakage of Fire Extinguisher Gas 
Environmental Health Perspectives  2006;114(11):1713-1717.
Although there are ample data on the respiratory effects of exposure to fire extinguisher gas, the potential hematologic effects have not been fully documented. We conducted this study to determine the possible etiologic agent(s) for a decrease in red blood cells among community residents in Taipei, Taiwan, after they were exposed to leakage of mixed fire extinguishants containing bromotrifluoromethane (CF3Br, Halon 1301), bromochlorodifluoromethane (CF2BrCl, Halon 1211), and dichlorodifluoromethane (CCl2F2, CFC-12).
Case presentation
We studied 117 exposed residents who came into one hospital for physical examinations. We also selected age- and sex-matched referents for comparison from residents who came to the same hospital for health examinations. Nine months after the exposure to mixed fire extinguishants, 91 of the exposed residents came back for a second physical examination. In the first examination of the exposed residents, we found a significant reduction in red blood cell count and hemoglobin and a relationship between dose and response.
After excluding iron-deficiency anemia, thalassemia, and other possible agents, we suspected that the hematologic effects might have resulted from pyrolytic products of CFC-12 and Halon 1211, which may contain phosgene, among other products.
Relevance to clinical practice
The acute transient hematologic effects observed in the exposed residents were associated with the incident of leakage of mixed fire-extinguisher gases and were most likely caused by a small amount of pyrolytic products, probably phosgene. Nine months after the exposure, we found a significant improvement in the abnormalities without any specific treatment.
PMCID: PMC1665423  PMID: 17107857
bromochlorodifluoromethane; bromotrifluoromethane; dichlorodifluoromethane; phosgene
9.  Effects of Particle Size Fractions on Reducing Heart Rate Variability in Cardiac and Hypertensive Patients 
Environmental Health Perspectives  2005;113(12):1693-1697.
It is still unknown whether the associations between particulate matter (PM) and heart rate variability (HRV) differ by particle sizes with aerodynamic diameters between 0.3 μm and 1.0 μm (PM0.3–1.0), between 1.0 μm and 2.5 μm (PM1.0–2.5), and between 2.5 μm and 10 μm (PM2.5–10). We measured electrocardiographics and PM exposures in 10 patients with coronary heart disease and 16 patients with either prehypertension or hypertension. The outcome variables were standard deviation of all normal-to-normal (NN) intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent NN intervals (r-MSSD), low frequency (LF; 0.04–0.15 Hz), high frequency (HF; 0.15–0.40 Hz), and LF:HF ratio for HRV. The pollution variables were mass concentrations of PM0.3–1.0, PM1.0–2.5, and PM2.5–10. We used linear mixed-effects models to examine the association between PM exposures and log10-transformed HRV indices, adjusting for key personal and environmental attributes. We found that PM0.3–1.0 exposures at 1- to 4-hr moving averages were associated with SDNN and r-MSSD in both cardiac and hypertensive patients. For an interquartile increase in PM0.3–1.0, there were 1.49–4.88% decreases in SDNN and 2.73–8.25% decreases in r-MSSD. PM0.3–1.0 exposures were also associated with decreases in LF and HF for hypertensive patients at 1- to 3-hr moving averages except for cardiac patients at moving averages of 2 or 3 hr. By contrast, we found that HRV was not associated with either PM1.0–2.5 or PM2.5–10. HRV reduction in susceptible population was associated with PM0.3–1.0 but was not associated with either PM1.0–2.5 or PM2.5–10.
PMCID: PMC1314907  PMID: 16330349
air pollution; autonomic system; epidemiology; heart rate variability; particulate matter
10.  Effects of Ambient Ozone Exposure on Mail Carriers’ Peak Expiratory Flow Rates 
Environmental Health Perspectives  2005;113(6):735-738.
The extent to which occupational exposure to ozone in ambient air can affect lung function remains unclear. We conducted a panel study in 43 mail carriers by measuring their peak expiratory flow rates (PEFRs) twice daily for 6 weeks in 2001. The daily exposure of each mail carrier to O3, particulate matter < 10 μm in aerodynamic diameter (PM10), and nitrogen dioxide was estimated by one air monitoring station in the center of the mail carrier’s delivery area. Hourly concentrations of air pollutants during their exposure periods were 6–96 ppb for O3, 11–249 μg/m3 for PM10, and 14–92 ppb for NO2. Linear mixed-effects models were used to estimate the association between air pollution exposures and PEFR after adjusting for subject’s sex, age, and disease status and for temperature and humidity. We found that night PEFR and the deviation in night PEFR were significantly decreased in association with 8-hr O3 exposures with a lag 0–2 days and by daily maximum O3 exposures with a lag of 0–1 day in our multipollutant models. By contrast, neither PM10 nor NO2 was associated with a PEFR reduction. Daily 8-hr mean concentrations of O3 had greater reduction effects on PEFR than did daily maximum concentrations. For a 10-ppb increase in the 8-hr average O3 concentration, the night PEFR was decreased by 0.54% for a 0-day lag, 0.69% for a 1-day lag, and 0.52% for a 2-day lag. We found that an acute lung function reduction occurs in mail carriers exposed to O3 concentrations below current ambient air quality standards and occupational exposure limits.
PMCID: PMC1257599  PMID: 15929897
deviation; lung function; mail carrier; ozone exposure; peak expiratory flow rate
11.  Personal Exposure to Submicrometer Particles and Heart Rate Variability in Human Subjects 
Environmental Health Perspectives  2004;112(10):1063-1067.
We conducted a study on two panels of human subjects—9 young adults and 10 elderly patients with lung function impairments—to evaluate whether submicrometer particulate air pollution was associated with heart rate variability (HRV). We measured these subjects’ electrocardiography and personal exposure to number concentrations of submicrometer particles with a size range of 0.02–1 μm (NC0.02–1) continuously during daytime periods. We used linear mixed-effects models to estimate the relationship between NC0.02–1 and log10-transformed HRV, including standard deviation of all normal-to-normal intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent NN intervals (r-MSSD), low frequency (LF, 0.04–0.15 Hz), and high frequency (HF, 0.15–0.40 Hz), adjusted for age, sex, body mass index, tobacco exposure, and temperature. For the young panel, a 10,000-particle/cm3 increase in NC0.02–1 with 1–4 hr moving average exposure was associated with 0.68–1.35% decreases in SDNN, 1.85–2.58% decreases in r-MSSD, 1.32–1.61% decreases in LF, and 1.57–2.60% decreases in HF. For the elderly panel, a 10,000-particle/cm3 increase in NC0.02–1 with 1–3 hr moving average exposure was associated with 1.72–3.00% decreases in SDNN, 2.72–4.65% decreases in r-MSSD, 3.34–5.04% decreases in LF, and 3.61–5.61% decreases in HF. In conclusion, exposure to NC0.02–1 was associated with decreases in both time-domain and frequency-domain HRV indices in human subjects.
PMCID: PMC1247378  PMID: 15238278
air pollution; autonomic system; epidemiology; heart rate variability; submicrometer particle
12.  SARS in Hospital Emergency Room 
Emerging Infectious Diseases  2004;10(5):782-788.
Thirty-one cases of severe acute respiratory syndrome (SARS) occurred after exposure in the emergency room at the National Taiwan University Hospital. The index patient was linked to an outbreak at a nearby municipal hospital. Three clusters were identified over a 3-week period. The first cluster (5 patients) and the second cluster (14 patients) occurred among patients, family members, and nursing aids. The third cluster (12 patients) occurred exclusively among healthcare workers. Six healthcare workers had close contact with SARS patients. Six others, with different working patterns, indicated that they did not have contact with a SARS patient. Environmental surveys found 9 of 119 samples of inanimate objects to be positive for SARS coronavirus RNA. These observations indicate that although transmission by direct contact with known SARS patients was responsible for most cases, environmental contamination with the SARS coronavirus may have lead to infection among healthcare workers without documented contact with known hospitalized SARS patients.
PMCID: PMC3323223  PMID: 15200809
Severe acute respiratory syndrome; healthcare workers; environmental contamination; real-time reverse transcriptase–polymerase chain reaction
13.  Effects of submicrometer particle compositions on cytokine production and lipid peroxidation of human bronchial epithelial cells. 
Environmental Health Perspectives  2003;111(4):478-482.
To identify the size and components related to toxicity of ambient particles, we used a trichotomous impactor to collect 17 sets of particles in three size ranges--submicrometer (diameters < 1 microm; PM1.0, fine (diameters between 1 and 2.5 microm; PM1.0-2.5, and coarse (diameters between 2.5 and 10 microm; PM2.5-10--at stations monitoring background, urban, traffic, and industrial air in Taiwan. Elemental contents, carbon contents, soluble ions, and endotoxin content of particles were determined by X-ray fluorescence spectrometry, thermal analysis, ion chromatography, and the Limulus amebocyte lysate assay, respectively. Human bronchial epithelial BEAS-2B cells were exposed to particle extracts at 100 micro g/mL for 8 hr, and interleukin-8 (IL-8) concentrations in the medium and lipid peroxidation products were measured. Particle-induced tumor necrosis factor-alpha (TNF-alpha) production by mouse macrophage RAW 264.7 cells was also measured. PM1.0 stimulation resulted in significantly higher IL-8 production and lipid peroxidation than PM2.5-10, whereas the responses elicited by PM1.0-2.5 were not significantly higher than blank filters. Untreated and polymyxin B-pretreated PM1.0 also stimulated more TNF-alpha production by RAW 264.7 cells than PM2.5-10 and PM1.0-2.5. Cytokine production was significantly associated with metal contents of PM1.0: IL-8 correlated with Cr and Mn, and TNF-alpha correlated with Fe and Cr. Lipid peroxidation in BEAS-2B cells correlated with elemental and organic carbon contents. Our study found that size and composition of ambient particles were both important factors in inducing cytokine production and lipid peroxidation.
PMCID: PMC1241431  PMID: 12676602
14.  Effects of concentrated ambient particles on heart rate and blood pressure in pulmonary hypertensive rats. 
Environmental Health Perspectives  2003;111(2):147-150.
Epidemiologic studies have shown that increased concentrations of ambient particles are associated with cardiovascular morbidity and mortality. However, the exact mechanisms remain unclear. Recent studies have revealed that particulate air pollution exposure is associated with indicators of autonomic function including heart rate, blood pressure, and heart rate variability. However, this association has not been clearly demonstrated in animal studies. To overcome the problems of wide variations in diseased animals and circadian cycles, we adopted a novel approach using a mixed-effects model to investigate whether ambient particle exposure was associated with changes in heart rate and blood pressure in pulmonary hypertensive rats. Male Sprague-Dawley rats were implanted with radiotelemetry devices and exposed to concentrated ambient particles generated by an air particle concentrator. The rats were held in nose-only exposure chambers for 6 hr per day for 3 consecutive days and then rested for 4 days in each week during the experimental period of 5 weeks. These animals were exposed to concentrated particles during weeks 2, 3, and 4 and exposed to filtered air during weeks 1 and 5. The particle concentrations for tested animals ranged between 108 and 338 micro g/m(3). Statistical analysis using mixed-effects models revealed that entry and exit of exposure chamber and particle exposure were associated with changes in heart rate and mean blood pressure. Immediately after particle exposure, the hourly averaged heart rate decreased and reached the lowest at the first and second hour of exposure for a decrease of 14.9 (p < 0.01) and 11.7 (p = 0.01) beats per minute, respectively. The hourly mean blood pressure also decreased after the particle exposure, with a maximal decrease of 3.3 (p < 0.01) and 4.1 (p < 0.01) mm Hg at the first and second hour of exposure. Our results indicate that ambient particles might influence blood pressure and heart rate.
PMCID: PMC1241341  PMID: 12573896

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