不同開發程度國家學齡前兒童血中鉛濃度變遷趨勢探討

Abstract

兒童鉛暴露一直是全世界關注的議題，鉛暴露可能會導致許多兒童健康上的危害，如：發育遲緩、降低智力等。而造成兒童鉛暴露的來源很多，像是使用有鉛汽油、含鉛油漆、鉛水管系統等。近年來，各國為了預防兒童鉛暴露實施許多不同的政策以降低環境中的鉛濃度，使得學齡前兒童血中鉛濃度持續下降。本研究即針對全球不同發展程度國家之學齡前兒童血中鉛濃度變化進行探討，並預估未來變動趨勢。 本研究利用PubMed及Google Scholar收集全世界2017年六月前出版有關一般學齡前兒童血中鉛濃度之中文或英文研究文獻，文獻中研究對象為1-8歲兒童且人數大於30人。另將文獻中各研究區域所在國家依據2015年聯合國人類發展指數分組為極高度人類發展指數國家、高度人類發展指數國家和中度及低度人類發展指數國家等三組。進一步將蒐集到之文獻中各組不同國家歷年之學齡前血中鉛濃度值取倒數後作線性迴歸分析，探討不同發展程度等級之國家學齡前兒童血中鉛濃度變化趨勢，推估2030年學齡前兒童血中鉛濃度值，並檢視不同發展程度國家之鉛暴露預防政策。 本研究總共納入108筆研究文獻，研究對象以收案時間為1988年至2013年間。其中56筆為極高度人類發展指數國家的研究文獻，37筆為高度人類發展指數國家研究文獻，15筆為中度及低度人類發展指數國家研究文獻。研究結果顯示，學齡前兒童血中鉛濃度在不同發展程度在過去24年間皆有明顯下降趨勢，且發展程度越好國家其學齡前兒童血中鉛濃度值越低。透過線性迴歸推估極高度人類發展指數國家、高度人類發展指數國家和中度及低度人類發展指數國家2030之年學齡前兒童血鉛濃度值分別為：0.74 ± 0.041 µg/dL、2.21 ± 0.22 µg/dL及2.85 ± 0.44 µg/dL。 本研究發現發展程度越好國家停用有鉛汽油的時間較早，並且對於油漆中、飲用水中的鉛含量普遍訂有規範。有鉛汽油在過去的文獻中被認為是血中鉛含量的主要暴露來源，在停用有鉛汽油後，學齡前兒童血中鉛濃度大幅度下降。此外，因為各國及各國際組織對於油漆、飲用水等暴露源制定鉛含量規範進行有效管制，使得目前影響學齡前兒童血中鉛含量的因素轉變為以各國特有的鉛暴露來源為主。 即便不同發展程度國家學齡前兒童血中鉛濃度均持續普遍下降中，但從本研究學齡前兒童血中鉛濃度趨勢圖發現，在不同發展程度國家之組別間，學齡前兒童血中鉛濃度仍有差距。由於不同發展程度國家之鉛暴露來源不盡相同，因此未來各國必須依據各自發展程度與鉛暴露特性採取不同的鉛暴露預防應變策略不同，以期有效進一步突破降低學齡前兒童血中鉛濃度之瓶頸。

Children’s exposure to lead is always of great concern all around the world. Lead exposure may cause many adverce health effects to children, such as attention deficit hyperactivity disorder (ADHD), reduced intelligence quotient, etc. There are many sources for children lead exposure, such as leaded gasoline, lead-based paint, water distribution with lead plumbing systems, etc. In recent years, countries have implemented various policies have been adopted by different countries to prevent lead exposure from children, resulting in significant and continuous decline in blood lead levels of preschool children. This study therefore aimed to explore the transition patterns of preschool children blood lead levels of variously developed countries around the world and predict their trends upcoming. In this study, PubMed and Google scholar were used as database for literature search. The inclusion criteria were literature written in English or Chinese, published by June, 2017, study subject aged 0 to 8 years old, and study population no less than 30 persons. All literatures were divided into three groups based on the 2015 Human Development Index(HDI) category which the study country belong to, i.e. ‘Very High Human Development’, ‘High Human Development’ and ‘Medium & Low Human Development’. The transitions of preschool children blood lead levels were analyzed using linear regression analysis by different human developmental category. Moreover, this study also predicted preschool children blood lead levels up to 2030 and scrutinized the policy for lead exposure prevention among countries of different human development categories. A total of 108 literatures, with study subjects being recruited from 1988 to 2013, were included in this study, 56 for very high human development countries, 39 for high human development countries, and 15 for medium and low human development countries. Results showed that the blood lead levels of preschool children continuously declined in the past 24 years, with the higher degree human development countries showing lower blood lead levels among preschool children. Through the linear regression analysis, the predicted preschool children blood lead levels in 2030 for very high human development countries, high human development countries and medium & low human development countries were 0.74 ± 0.041 µg/dL、2.21 ± 0.22 µg/dL and 2.85 ± 0.44 µg/dL respectively. It was observed that the higher the degree of human development, the earlier the country ceased the use of leaded gasoline, and tended to set thorough lead control act on paint and drinking water. Leaded gasoline was thought the major source for blood lead level. After the cease of leaded gasoline use, preschool children's blood lead level decreased significantly. Furthermore, due to effective control of lead contents in paint, drinking water and other sources by different countries and international organizations, currently the affecting factors for preschool children blood lead levels are mostly attributed to country-specific lead exposure sources, such as traditional medicine use, ethnic activity, etc. Though the preschool children lead blood levels decline continuously, there still was a gap in preschool children blood lead level across countries of different human development category. Since every country need to have her own lead exposure prevention strategies in order to further reduce preschool children’s blood lead level.