| Summary: | 碩士 === 國立臺灣大學 === 公共衛生碩士學位學程 === 105 === 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.
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