ScienceDaily (Nov. 16, 2009) — A study of 145 preschool children reports,
for the first time, that when the concentrations of two common phthalates in
mothers' prenatal urine are elevated their sons are less likely to play with
male-typical toys and games, such as trucks and play fighting.
有兩種在孕婦尿液中的磷苯二甲酸濃度被發現和孩子是否喜歡玩男性化的玩具或遊戲有關
。男性化玩具或遊戲指的是打架、卡車等。
The University of Rochester Medical Center-led study is published in the
International Journal of Andrology.
Because testosterone produces the masculine brain, researchers are concerned
that fetal exposure to anti-androgens such as phthalates -- which are
pervasive in the environment -- has the potential to alter masculine brain
development, said lead author Shanna H. Swan, Ph.D., professor of Obstetrics
and Gynecology, director of the URMC Center for Reproductive Epidemiology,
and an expert in phthalates.
"Our results need to be confirmed, but are intriguing on several fronts,"
Swan said. "Not only are they consistent with our prior findings that link
phthalates to altered male genital development, but they also are compatible
with current knowledge about how hormones mold sex differences in the brain,
and thus behavior. We have more work to do, but the implications are
potentially profound."
Phthalates are chemicals used to soften plastics. Recent studies have shown
that the major source of human exposure to the two phthalates of most concern
(DEHP and DBP) is through food. These phthalates are used primarily in
polyvinyl chloride (PVC), so any steps in the processing, packaging, storage,
or heating of food that use PVC-containing products can introduce them into
the food chain.
Phthalates are also found in vinyl and plastic tubing, household products,
and many personal care products such as soaps and lotions. Phthalates are
becoming more controversial as scientific research increasingly associates
them with genital defects, metabolic abnormalities, and reduced testosterone
in babies and adults. A federal law passed in 2008 banned six phthalates from
use in toys such as teethers, play bath items, soft books, dolls and plastic
figures.
In Swan's study, higher concentrations of metabolites of two phthalates,
di(2-ethylhexyl) phthalate (DEHP), and dibutyl phthalate (DBP), were
associated with less male-typical behavior in boys on a standard play
questionnaire. No other phthalate metabolites measured in-utero was linked to
the less-masculine behavior. Girls' play behavior was not associated with
phthalate levels in their mothers, the study concluded.
Swan's interest in phthalates stems from an investigation into the
environmental causes of reproductive health problems. Since 1998 she has led
the federally funded, multi-center Study for Future Families (SFF), which
established a large database from which to explore various scientific
questions about toxins.
The current study focused on a small sample of SFF mothers who delivered
children between 2000 and 2003. The mothers provided urine samples around the
28th week of pregnancy. The urine was analyzed for phthalate metabolites by
the Centers for Disease Control and Prevention (CDC).
Swan hypothesized that phthalates may lower fetal testosterone production
during a critical window of development -- somewhere within eight to 24 weeks
gestation, when the testes begin to function -- thereby altering brain sexual
differentiation.
To explore the question, researchers reconnected with mothers from the SFF
sample and asked them to complete a standard research questionnaire, called
the Preschool Activities Inventory (PSAI), for their children ages 3 1/2 to 6
1/2 years.
The PSAI is designed to discriminate play behavior within and between the
sexes, and in the past has been shown to reflect the endocrine-disrupting
properties of other toxins, such as PCBs and dioxins. The PSAI addressed
three aspects of play: types of toys children choose (trucks versus dolls),
activities (rough-and-tumble play, for example), and child characteristics.
However, researchers were concerned about how the choice of toys available in
any given household might skew results, so in addition they asked about
parental views toward atypical play. For example, the survey asked, "What
would you do if you had a boy who preferred toys that girls usually play
with?" The possible answers included "strongly encourage" (him to play this
way) to "strongly discourage."
The final survey scores are designed to reflect sex-typical play. Higher
scores meant more male-typical play and lower scores meant more
female-typical play.
Researchers then examined boys play-behavior scores in relation to the
concentration of phthalate metabolites in their mothers' prenatal urine
samples, finding that higher concentrations of DEHP and DBP metabolites were
associated with less masculine play behavior scores.
Earlier studies by Swan and others have shown that phthalate exposure during
pregnancy might affect the development of genitals of both male rodents and
baby boys. Scientists refer to this cluster of genital alterations as the
"phthalate syndrome," and research suggests that in rodent pups, the syndrome
can have adverse consequences for later sexual development.
If endocrine disrupters such as phthalates can impair genital development and
hormone levels in the body, the play-behavior study noted, then a deeper
examination of how these chemicals impact the brain is warranted.
==
原始網址：
http://www.sciencedaily.com/releases/2009/11/091116085040.htm
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作者: mulkcs (mulkcs) 看板: Cognitive
標題: Re: [新知] Phthalate Exposure Linked to Less-Ma …
時間: Sat Nov 21 16:11:59 2009
鄰苯二甲酸酯暴露與男孩女性化玩耍之先導研究
Pilot study relates phthalate exposure to less-masculine play by boys
http://www.physorg.com/news177573699.html
November 16, 2009
一項針對 145 未學齡前兒童的研究首度報告：當母親產前尿液中二種常見鄰苯二甲酸酯
（phthalates）的濃度升高時，她們的兒子不太喜歡玩男性特有的（male-typical）玩具
與遊戲，例如卡車與打打鬧鬧。
這項由 Rochester 大學醫學中心所領導的研究發表在 International Journal of
Andrology 上。
因為睪固酮（testosterone）產生男性化（masculine）腦袋，所以研究者憂慮，嬰兒暴
露在抗雄激素（anti-androgens）的情況下 -- 例如鄰苯二甲酸酯，那在環境中很普遍
-- 有可能改變男性腦部的發展，領導作者 Shanna H. Swan, Ph.D. 表示，URMC 生殖流
行病學中心婦產科教授，同時也是一位鄰苯二甲酸酯專家。
"我們的結果需經確認，不過在幾個面向上令人好奇，" Swan 表示。"不僅因為它們與我
們先前的發現相符 -- 那將鄰苯二甲酸酯連結至男性生殖器官的生長 -- 而且那也與目前
對於「荷爾蒙如何在腦中塑造出性別與行為差異」的認知相容。我們需要進行更多研究，
但牽連可能相當深遠。"
鄰苯二甲酸酯是用於軟化塑膠的化學物質。最近研究證明，人類暴露於二種最受關切之鄰
苯二甲酸酯（DEHP 與 DBP）的主要來源是透過食物。這些鄰苯二甲酸酯主要用於聚氯乙
烯（PVC）當中，故在食物處理、包裝、儲存或加熱的任何步驟中使用了包含 PVC 的產品
，就能將它們引入食物鏈當中。
鄰苯二甲酸酯也能在乙烯基（vinyl）和塑膠管、家用產品以及許多個人照護產品中找到
，例如肥皂與化妝水。當愈來愈多的科學研究使鄰苯二甲酸酯關聯到遺傳缺陷、新陳代謝
異常以及嬰兒與成人身上睪固酮的減少後，它變得更具爭議性。一項在 2008 年通過的聯
邦法律禁止在玩具 -- 如固齒器、洗澡玩具、洗澡書（soft books）、洋娃娃與塑膠人偶
-- 中使用六種鄰苯二甲酸酯。
在 Swan 的研究裡，二種鄰苯二甲酸酯代謝物 -- 鄰苯二甲酸二(2-乙基已基)酯（
di(2-ethylhexyl) phthalate，DEHP）與鄰苯二甲酸二丁酯（dibutyl phthalate，DBP）
-- 的更高濃度與一份標準玩耍問卷中，男孩的較少男性特有行為相關。在子宮內（
in-utero）所測得的其他鄰苯二甲酸酯代謝物並不會與較少男性化行為相關。這項研究下
結論表示：女孩的玩耍行為與她們母親體內的鄰苯二甲酸酯濃度無關。
Swan 對於鄰苯二甲酸酯的關注源於一次針對生殖健康問題之環境起因的調查。從 1998
年起，她領導聯邦資助的、多中心的 Study for Future Families（SFF），那建立一套
大型資料庫，藉此探索關於毒素的各種科學問題。
目前研究則聚焦在 2000 與 2003 年間生小孩的 SFF 母親小型樣本上。這些母親在懷孕
約 28 週時提供尿液樣本。這些尿液則透過 CDC 來分析鄰苯二甲酸酯代謝物。
Swan 假設，鄰苯二甲酸酯也許會在生長的關鍵時期（critical window）降低嬰兒的睪固
酮製造 -- 約在懷孕 8 到 24 週之內，那時睪丸開始運作 -- 因而改變了腦部的性別差
異。
為探索此問題，研究者透過 SFF 樣本與母親們重新聯繫，並要求她們為她們 3.5 歲到
6.5 歲的小孩完成一份標準研究問卷，稱為 Preschool Activities Inventory（PSAI，
學齡前活動細目）。
PSAI 被設計成用以區分性別內與性別間的玩耍行為，且在過去經證明能反應出其他毒素
（例如 PCBs 與戴奧辛）的內分泌擾亂特性。PSAI 對付玩耍的三個觀點：小孩所選擇的
玩具類型（卡車 vs. 洋娃娃）、活動（例如混亂的玩）以及小孩的特性。
然而，研究者擔憂「任一戶人家如何選擇玩具」也許會扭曲結果，所以她們額外詢問父母
親關於反常玩耍的觀察。例如，該調查問及「如果你的小男孩喜歡玩女生通常會玩得玩具
，你會怎麼辦？」可能回答則包括「強烈鼓勵（應該隨其所好）」到「強烈反對」。
最終調查分數則被設計成反應出同性別的（sex-typical）玩耍。分數愈高則表示更男性
化的玩耍，而分數愈低則意味著更女性化的遊戲。
研究者接著檢查母親產前尿液樣本中鄰苯二甲酸代謝物的濃度與男孩玩耍行為分數間的關
係，發現更高濃度的 DEHP 與 DBP 代謝物與較少的男性玩耍行為分數相關。
Swan 等人的早期研究證明，在懷孕期間的鄰苯二甲酸酯暴露也許會影響雄性囓齒目動物
與小男嬰的生殖器發展。科學家將這一連串生殖器的改變說成「鄰苯二甲酸酯併發症（
phthalate syndrome）」，而研究指出，在囓齒目動物的幼小動物身上，這種症候群對其
後性別發展會有負面的後果。
這個玩耍行為研究提到，如果像鄰苯二甲酸酯那樣的內分泌擾亂能損害生殖器的發展與減
少體內的荷爾蒙濃度，那麼這些化學物質如何影響腦部的深入檢查有其必要性。
※ 相關報導：
＊ Prenatal phthalate exposure and reduced masculine play in boys
http://www3.interscience.wiley.com/journal/122685135/abstract
S. H. Swan, F. Liu, M. Hines, R. L. Kruse, C. Wang,
J. B. Redmon, A. Sparks and B. Weiss
International Journal of Andrology, 2009.11.16
doi: 10.1111/j.1365-2605.2009.01019.x
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原始網址：
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