Shang-Shyue Tsai

Arsenic in drinking water and adverse pregnancy outcome in an arseniasis-endemic area in northeastern Taiwan

The well water in Lanyang Basin, which is located in the northeastern portion of Taiwan island, was found to have high levels of arsenic ranging from undetectable levels (<0.15 ppb) to 3.59 ppm. We performed a study to compare the risk of adverse pregnancy outcomes (preterm delivery and birthweight) between an area with historic high well water arsenic levels (arsenic-exposed area (AE)) and a comparison area with no historic evidence of arsenic water contamination (non-arsenic-exposed area (NAE)). The mean birth weight in the AEs and NAEs were 3132.6 and 3162.6 g, respectively. Babies born in AEs were on average 30 g lighter than those born in NAEs. AEs had a higher rate of preterm delivery than NAEs (3.74% vs 3.43%). The results of this study suggest that, after adjustment for potential confounders, arsenic exposure from drinking well water was associated, although not significantly, with the risk of preterm delivery, with an odds ratio of 1.10 (0.91-1.33). The estimated reduction in birth weight was 29.05 g (95% CI=13.55-44.55). The findings from this investigation provide evidence for a potential role for arsenic exposure through drinking water in increasing the risk of low birthweight.

Calcium, magnesium, and nitrate in drinking water and gastric cancer mortality.

The possible association between the risk of gastric cancer and the levels of calcium, magnesium, and nitrate in drinking water from municipal supplies was investigated in a matched case‐control study in Taiwan. Records of gastric cancer deaths among eligible residents in Taiwan from 1987 through 1991 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair‐matched to the cases by sex, year‐of‐birth, and year‐of‐death. Each matched control was selected randomly from the set of possible controls for each case. Data on calcium, magnesium, and nitrate levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation. The municipality of residence of the cases and controls was assumed to be the source of the subjects calcium, magnesium, and nitrate exposure via drinking water. The subjects were divided into tertiles according to the levels of calcium, magnesium, and nitrate in their drinking water. The results of the present study show that there is a significant positive association between drinking water nitrate exposure and gastric cancer mortality. The present study also suggests that there was a significant protective effect of calcium intake from drinking water on the risk of gastric cancer. Magnesium also exerts a protective effect against gastric cancer, but only for the group with the highest levels.

Correlation of Asian Dust Storm Events with Daily Clinic Visits for Allergic Rhinitis in Taipei, Taiwan

In spring, windblown dust storms originating in the deserts of Mongolia and China head toward Taipei city. These occurrences are known as Asian dust storm (ADS) events. The objective of this study was to assess the possible associations of ADS on the daily clinical visits for allergic rhinitis of residents in Taipei, Taiwan, during the period 1997–2001. Forty-nine dust storms were identified and classified as index days. Daily clinical visits for allergic rhinitis on the index days were compared with clinical visits on the comparison (non-ADS) days. Two non-ADS days for each index day, 7 d before the index day and 7 d after the index day, were selected. The effects of dust storms on clinic visits for allergic rhinitis were prominent 2 d after the event (19%). However, the association was not statistically significant. There may not have been enough power to detect associations resulting from the inadequate sample size of allergic rhinitis visits on ADS days. Further study is needed to clarify this association.

ISCHEMIC HEART DISEASE MORTALITY REDUCTION IN AN ARSENIASIS-ENDEMIC AREA IN SOUTHWESTERN TAIWAN AFTER A SWITCH IN THE TAP-WATER SUPPLY SYSTEM

Arsenic has been identified as a major contributing risk factor for development of blackfoot disease (BFD), a unique peripheral vascular disease that was endemic to the southwestern coast of Taiwan, where residents imbibed artesian well water continuing high amounts of arsenic for more than 50 yr. Chronic arsenic exposure was found to be associated with ischemic heart disease (CHD) in a dose-dependent manner. A tap-water supply system was implemented in the early 1960s in the BFD-endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to examine whether CHD-related mortality decreased after consumption of high-arsenic-containing artesian well water ceased and, if so, when the reduction occurred. Standardized mortality ratios (SMRs) for CHD were calculated for the BFD endemic area for the years 1971–2000. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. Data show that mortality attributed to CHD declined gradually for approximately 17 to 20 yr following cessation of consumption of high-arsenic artesian well water. Based on the reversibility criterion, the association between arsenic exposure an1rd CHD-related mortality is likely to be causal.

Epidemiological features of biliary atresia in Taiwan, a national study 1996–2003

Background and Aim:  The incidence of biliary atresia (BA) varies among different countries. It is supposed to be higher in Asian countries than in Western countries; however, the incidence of BA in Taiwan has not been well investigated. The aim of this study was to analyze the epidemiological characteristics and the incidence of BA in Taiwan.

Adverse pregnancy outcome in a petrochemical polluted area in Taiwan.

The petrochemical industry is the main source of industrial air pollution in Taiwan. Reported here are the results from an ongoing study of outdoor air pollution and the health of individuals living in a community in close proximity to petrochemical industrial complexes. The prevalences of term low birth weight (LBW) in the petrochemical municipality and control municipality were 3.22% and 1.84%, respectively. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.767 (1.002-3.116) for term LBW in the petrochemical municipality. Data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.

Relationship between air pollution and daily mortality in a tropical city: Kaohsiung, Taiwan.

Air pollution has been associated with daily mortality in numerous studies over the past decade. However, most of these studies were conducted in the United States and Europe, with relatively few done in Asia. In this study, the association between ambient air pollution and daily mortality in Kaohsiung, Taiwan, a large industrial city with a tropical climate, was investigated for the period 1994-2000 using a case-crossover analysis. This design is an alternative to Poisson time-series regression for studying the short-term adverse health effects of air pollution. The air pollutants examined included particulate matter (PM 10 ), sulfur dioxide (SO 2 ), ozone (O 3 ), nitrogen dioxide (NO 2 ), and carbon monoxide (CO). No significant effects were found between PM 10 and SO 2 exposure levels and respiratory-related mortality. The well-established link between air pollution levels and daily mortality may not be as strong in cities in tropical areas, although other factors such as differences in pollutant mixtures or underlying health of the population may explain the lack of a strong association in this study. Further studies of this type in cities with varying climates and cultures are needed.

Increased risk of preterm delivery in areas with air pollution from a petroleum refinery plant in Taiwan.

The petrochemical and petroleum industries are among the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to a petroleum refinery plant. The prevalence of delivery of preterm birth infants was significantly higher in mothers living in a petroleum refinery area compared to controls in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.41 (95% CI = 1.08-1.82) for delivery of preterm infants in the polluted region. Data support the view that air pollution can affect the outcome of pregnancy.

Analgesic use and the risk for progression of chronic kidney disease

The chronic effect of various analgesics on the progression of chronic kidney disease (CKD) is inconclusive. There is also lack of information on the renal safety of selective cyclooxygenase‐2 (COX‐2) inhibitors. This study aimed to clarify the renal risk of analgesic use in CKD patients.

Female Lung Cancer and Petrochemical Air Pollution in Taiwan

To investigate the relationship between petrochemical air pollution and female lung cancer, we conducted a matched case-control study among women who had died in Taiwan from 1990 through 1994. Data about all eligible female lung cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group included women who died from nonneoplasms and diseases that were not associated with respiratory problems. We pair-matched the controls to the cases by sex, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. We used the proportion of a municipalitys total population employed in the petrochemical manufacturing industry as an indicator of a residents exposure to air emissions from the petrochemical manufacturing industry. The subjects were divided into tertiles according to the above indicator. Women who lived in the 2 groups of municipalities characterized by higher levels of petrochemical pollution had a statistically significant higher risk of developing lung cancer than the group that lived in municipalities with the lowest petrochemical air pollution levels (after controlling for possible confounders). The linear trend was also statistically significant (p < .05). The results of this study shed important light on the relationship between the Taiwan petrochemical industry and the resulting risk to human health.