焚化爐產生之大氣戴奧辛暴露與生殖危害之相關性研究

Ambient Dioxin Exposure to Incinerators in Association with Adverse Birth Outcomes

林志銘(Chih-Ming Lin) ； 李中一(Chung-Yi Li) ； 毛義方(I-Fang Mao)

《台灣公共衛生雜誌》 21卷3期 (2002/06) Pp. 197-206

https://doi.org/10.6288/TJPH2002-21-03-06

摘要

Objectives: To investigate the relationship between ambient exposure to incinerator generated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the risks of adverse birth outcomes. Methods: We used a cross-sectional design in Taipei metropolitan areas to explore the relationship between exposure too elevated PCDD/Fs concentration and various birth outcomes in 1991 (one year before the incinerator started to operate) and 1997 (four years later), respectively. With the US EPA Industrial Source Complex Model-Sort Term modeling technique, we determined the ambient PCDD/Fs concentrations within the catchments of the study areas in which 40 districts with PCDD/Fs exposure of ＞= 0.03 pg TEQ/m3 were considered ill1~il1y exposed areas, whereas the lowly exposed areas comprised the same number of districts with an estimated exposure of zero. Information on birth outcomes was retrieved from Taiwan’s Birth Registry. The study participants included all singletons. For multiple births, we also randomly selected one of them as the ruuay participant. The exclusion criteria included a gestation age of ＜20 weeks or a birth weight of ＜ 500 grams. These rules gave rise to a total of 6994 and 6520 neonates included in the analysis for 1991 and 19997, respectively. Results: Multivariate analysis indicated that the 1991 or 1997 year specific odds ratios (Ors) of low birth weight (OR= 1.08 or 1.06), preterm (OR= 1.06 or 1.15), term low birth weight (OR=0.98 or 0.74), being females (OR=0.96 or 0.94), and multiple birth (OR=0.94 or 1.46) in relation to higher exposure to PCDD/Fs were all close to unity, and were statistically insignificant. Test of heterogeneity in Ors further suggested no significant difference between the two year-specific Ors for all birth outcomes. As birth weight was analyzed as a continuous variable, the high/low exposure difference in mean birth weight decreased from 7.36 grams in 1991 to –2.16 grams in 1997. However, the above year-specific high/low exposure differences in mean birth weight were close to null statistically. Conclusions: The study tends to suggest little influence of the operation of incinerators on the risk of adverse birth outcomes. However, the use of modeling for exposure characterization might entail a certain degree of exposure misclassification in the study. Additionally, it is somewhat arbitrary to use a level of 0.03 pg TEQ/m3. This might be lower than the threshold concentration that can affect the risk of adverse birth outcomes as a cutoff point in discriminating highly from lowly exposed areas. Hence, the null findings of the study could be the result of information bias.

關鍵字

戴奧辛及呋喃 ； 斷代研究 ； 暴露評估 ； 生殖危害 ； 低出生體重

並列摘要

Objectives: To investigate the relationship between ambient exposure to incinerator generated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the risks of adverse birth outcomes. Methods: We used a cross-sectional design in Taipei metropolitan areas to explore the relationship between exposure too elevated PCDD/Fs concentration and various birth outcomes in 1991 (one year before the incinerator started to operate) and 1997 (four years later), respectively. With the US EPA Industrial Source Complex Model-Sort Term modeling technique, we determined the ambient PCDD/Fs concentrations within the catchments of the study areas in which 40 districts with PCDD/Fs exposure of ＞= 0.03 pg TEQ/m3 were considered ill1~il1y exposed areas, whereas the lowly exposed areas comprised the same number of districts with an estimated exposure of zero. Information on birth outcomes was retrieved from Taiwan’s Birth Registry. The study participants included all singletons. For multiple births, we also randomly selected one of them as the ruuay participant. The exclusion criteria included a gestation age of ＜20 weeks or a birth weight of ＜ 500 grams. These rules gave rise to a total of 6994 and 6520 neonates included in the analysis for 1991 and 19997, respectively. Results: Multivariate analysis indicated that the 1991 or 1997 year specific odds ratios (Ors) of low birth weight (OR= 1.08 or 1.06), preterm (OR= 1.06 or 1.15), term low birth weight (OR=0.98 or 0.74), being females (OR=0.96 or 0.94), and multiple birth (OR=0.94 or 1.46) in relation to higher exposure to PCDD/Fs were all close to unity, and were statistically insignificant. Test of heterogeneity in Ors further suggested no significant difference between the two year-specific Ors for all birth outcomes. As birth weight was analyzed as a continuous variable, the high/low exposure difference in mean birth weight decreased from 7.36 grams in 1991 to –2.16 grams in 1997. However, the above year-specific high/low exposure differences in mean birth weight were close to null statistically. Conclusions: The study tends to suggest little influence of the operation of incinerators on the risk of adverse birth outcomes. However, the use of modeling for exposure characterization might entail a certain degree of exposure misclassification in the study. Additionally, it is somewhat arbitrary to use a level of 0.03 pg TEQ/m3. This might be lower than the threshold concentration that can affect the risk of adverse birth outcomes as a cutoff point in discriminating highly from lowly exposed areas. Hence, the null findings of the study could be the result of information bias.

並列關鍵字

PCDD/Fs ； cross-sectional study ； exposure assessment ； adverse birth outcomes ； low birth weight

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