重金屬暴露與六輕石化工業區附近幼兒園孩童氧化壓力之相關及飲食中抗氧化物可能的保護效果

The Association of Heavy Metal Exposure and Oxidative Stress on Kindergarten Children Living near the No.6 Naphtha Cracking Plant and the Potential Protective Effect of Dietary Antioxidant Intake on Oxidative Damage

柯昀君(Brittany Killian)

指導教授 ： 詹長權

共同指導教授 ： 林先和 ； 蔡政憲

國立臺灣大學/公共衛生學院/公共衛生碩士學位學程/碩士(2017年)

https://doi.org/10.6342/NTU201702477

摘要

背景: 氧化壓力被認為是空氣污染對人類造成健康危害的機制之一。氧化壓力的形成是因體內氧化物與抗氧化物的不平衡所造成的，並與呼吸系統疾病、慢性病等健康效應與整體死亡率和發病率相關。從工業區排放出的空氣粉塵微粒內所含的重金屬也被假設為造成氧化壓力的原因之一。兒童是氧化壓力的易感受族群，淺在的健康危害包括從呼吸系統疾病到神經損害等。近年，研究推測, 透過飲食攝取的抗氧化物可能能夠對氧化壓力達到保護作用。
目的: 本研究的目的是探討營養與污染狀況的社會決定因子、判定從飲食攝取之抗氧化物是否會產生保護作用以預防氧化傷害、並評估臺灣雲林六輕石化工業區附近幼稚園兒童的氧化壓力是否與其重金屬暴露呈現正相關。
方法: 本研究招募了168名4-8歲的兒童，其中87名來自預先定義的高暴露區域、81名來自低暴露區域。本橫斷面研究特別開發了一半定量的飲食頻率問卷(Food Frequency Questionnaire, FFQ)來評估受試者的抗氧化物攝取、飲食習慣以及社經地位特性。同時, 填寫FFQ時每位受試者也收集了晨尿樣本。研究團隊與營養師分析FFQ，以確定每位受試者每週的總抗氧化物攝取量。尿液樣本則是以電感耦合等離子體質譜 (ICP) 和液相色譜質譜 (LC) 進行分析，偵測十一種重金屬和四種氧化壓力生物標記的濃度。群體之間社會經濟、飲食和暴露因子的差異是以ANCOVA 測試檢定。本研究採用多元線性回歸法判定尿液氧化壓力的顯著預測因子。
結果: ANCOVA 檢定發現高、低暴露組在尿液中 8-OHdG 和8種重金屬元素 (mg/g-creatinine) 有顯著差異，而高暴露組的平均濃度高於低暴露組。受試者住址和幼稚園地址離暴露源的距離加權平均是尿液中重金屬元素濃度的重要預測因子。飲食習慣雖觀察到有差異，但並不具統計意義。多線性回歸檢定顯示高尿中重金屬元素與高尿中8-OHdG呈現相關。每週總抗氧化劑攝取量 (mol/g) 的增加導致尿液中 8-OHdG 的減少，但未達統計顯著。
結論和建議: 本研究提供社會經濟因子、空氣污染和營養之間的關聯資料。在靠近石化工業園區的族群中的尿液重金屬和氧化壓力濃度較高，顯示暴露的風險增加。飲食中的抗氧化物攝入與較低的氧化壓力雖呈現相關，但並未達到統計意義，顯示目前本研究平均普遍較低的抗氧化物攝取尚不足對氧化壓力達到保護作用。本研究建議對本研究族群進一步探討，以確定較高的飲食中抗氧化物攝取是否會對氧化壓力產生保護作用，並調查除了重金屬外以外其他的氧化壓力來源。此外、也建議對工業排放污染進行更嚴格的管制，以減少對研究族群的暴露。

關鍵字

重金屬 ； 兒童 ； 氧化壓力 ； 抗氧化物 ； 工業汙染

並列摘要

Background: Air pollution is believed to cause harmful human effects in part through the mechanism of oxidative stress. Oxidative stress occurs when there is an imbalance between oxidants and antioxidants in the body, and it is associated with many human health effects, including respiratory diseases, chronic diseases, and overall mortality and morbidity. Heavy metals, present in particulate matter linked to industrial complexes, have been hypothesized as a cause of oxidative stress. Children are particularly vulnerable to oxidative stress, with potential health effects ranging from respiratory disease to neurological damage. Researchers recently have hypothesized that dietary antioxidant intake might provide a protective effect against oxidative stress.
Objective: The objective of this study is to investigate the social determinants of health of nutritional and pollution status, to determine whether dietary antioxidant intake plays a protective role in preventing oxidative damage, and to assess whether oxidative stress is positively associated with heavy metal exposure in kindergarten children living near a petrochemical complex in Yunlin County, Taiwan.
Methods: 168 children ages 4-8 were recruited, 87 from the pre-determined high exposure area and 81 from the pre-determined low exposure area. This cross-sectional study used a specially-developed semi-quantitative food frequency questionnaire (FFQ) to assess the participants’ intake of antioxidants, overall dietary patterns, and socioeconomic characteristics. A morning spot urine sample was collected from each participant at the same time as the FFQ. The FFQ was analyzed with nutritionists to determine each participant's’ total antioxidant intake per week. The urine samples were analyzed using Inductively coupled plasma mass spectrometry (ICP-MS) and liquid chromatography mass spectrometry (LC-MS) to find concentrations of eleven heavy metals and four biomarkers for oxidative stress. ANCOVA tests were performed to determine between-group differences in socioeconomic, dietary, and exposure variables. Multiple linear regression was performed to determine significant predictors of urinary oxidative stress.
Results: ANCOVA tests revealed significant differences in urinary 8-OHdG and eight heavy metals (g/g-creatinine) between the high and low exposure group, with the high exposure group’s average concentrations higher than the low exposure group’s. Weighted average distance of the participants’ home and kindergarten addresses to the exposure site was a significant predictor of urinary heavy metal concentrations. Dietary differences were observed but they were not statistically significant. Multiple linear regression tests showed higher urinary heavy metal concentrations associated with higher urinary 8-OHdG. Increased total antioxidant intake per week (mmol/g) resulted in a decrease in urinary 8-OHdG, but these results were not statistically significant.
Conclusion and Recommendations: This study provided data on the associations between socioeconomic factors, air pollution, and nutrition. Heavy metals and oxidative stress were higher in the group living closer to the petrochemical plant, indicating an increased risk of exposure. Dietary antioxidant intake was associated with lower oxidative stress, but these results were not statistically significant, indicating that the current dietary intake of antioxidants, which is lower than average, is not enough to protect this population from urinary oxidative stress. It is recommended that further studies be done on this population to determine if a higher intake of dietary antioxidants would provide a protective effect against oxidative stress, as well as investigate other sources of oxidative stress besides heavy metal exposure. In addition, stricter regulation of industrial pollution to reduce exposure for the study population is also recommended.

並列關鍵字

Heavy metals ； children ； oxidative stress ； antioxidants ； industrial pollution

參考文獻

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