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zoom RSS 自閉症増加は環境汚染ではなく親の学歴と関連/米国カリフォルニア

<<   作成日時 : 2010/01/14 01:55   >>

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画像 カリフォルニアの10地域で自閉症の発症増加がみられるが、地域の環境汚染との関連はないという。南カリフォルニアとサンフランシスコ湾地域では親の教育歴と関連があるとわかった。6つの地域では大学卒の親と高校卒業していない親では発症リスクに4倍の差があったと報告された。
 自閉症の遺伝的な素因は明瞭にあるが、出生前や乳幼児期早期の環境が関連しているという多くの事実が明らかになってきている。従って、妊娠後期や新生児期早期に暴露した場所を考慮した新たな発症増加の発見法を適用した。
 1996-2000年にカリフォルニアで生まれた240万人のうち、2006年2月時点で9,900人が自閉症であった。このデータベースには全ての子どもの75-80%が登録されていると概算されている。地理的な分析により、21の地域発達サービスセンター所管のうち8つの地域で発症増加が見られた。
 10地域では7つのテストで周辺地域より少なくとも70%以上リスクが高く、さらに2つの地域は7つのテストのうち少なくとも4つで陽性だった。
 10地域のうち6つでは、自閉症の割合は親が大卒の場合は未高卒の1/4 4倍であった。
 しかし、完全に環境因子を除外できたわけではなく、高学歴と関連した環境要因を除外できたわけでもない。
The Golden Gate portion of San Francisco;
The area around Redwood City in the San Francisco Bay area;
The area around Sunnyvale and Santa Clara in the southern portion of the San Francisco Bay Area (Silicon Valley);
A small area around Modesto in the Central Valley of California;
The Fresno area, also in California's Central Valley;
The catchment area that includes Thousand Oaks in the Los Angeles region;
The area surrounding Beverly Hills;
The catchment area around Los Angeles that includes Norwalk and Cerritos;
The Los Angeles-region that includes Redondo Beach and Torrance;
The San Diego catchment area;
The Southern California catchment area that includes Dana Point and Mission Viejo.
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自閉症スペクトラムの急増/米国 CDC
http://kurie.at.webry.info/200912/article_26.html
100人に1人が自閉症/米国
http://kurie.at.webry.info/200910/article_8.html
高齢出産による自閉症のリスク
http://kurie.at.webry.info/200907/article_11.html
自閉症の急激な増加/米国 カリフォルニア
http://kurie.at.webry.info/200901/article_26.html
脳内蛋白の欠如により自閉症が発症の可能性
http://kurie.at.webry.info/200802/article_24.html
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California Autism Clusters Tied to Parents' Education, Not Environment
Unusually High Autism Rates in Some Areas Not Tied to Environmental Causes
By CRYSTAL PHEND
MedPage Today Staff Writer
Jan. 9, 2010
http://abcnews.go.com/Health/AutismNews/education-level-environment-tied-autism-clusters/story?id=9514773

Researchers have found clusters of autism in 10 areas around California -- but with no suggestion of a link to local pollution or other environmental exposures, they said.
California Autism Clusters Tied to Parents' Education, Not Environment
Researchers have found clusters of autism in 10 areas around California -- but with no suggestion of a link to local pollution or other environmental exposures, they said.
(ABC News Photo Illustration)

Instead, the only consistent factor among the areas -- identified largely in Southern California and the San Francisco Bay region -- was a population of well-educated parents, Karla Van Meter of the University of California Davis and colleagues found.

In six of the clusters, a college-educated parent conferred a risk of autism that was more than four times as great as a parent who didn't graduate from high school, they reported online in Autism Research.

"At this point, we don't think that's due to differences in the actual rates," coauthor Irva Hertz-Picciotto, also of UC Davis, told MedPage Today.

The observational study determined autism cases through a database of state-sponsored developmental services, a system which relies on parents to voluntarily seek services.
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Parents with higher education are likely to be better insured and more attuned to seek diagnosis and services for their autistic children than less-educated parents -- an effect seen in prior studies, the researchers said.

The clear-cut link with mom and dad's education should be reassuring to parents living in the cluster areas, Hertz-Picciotto said.

"There was such a uniform pattern across all of these clusters [linking higher education to autism rates]," she said. "This is really not something people should be worried about who are living in those areas."

The real concern was that local pollution sources, such as dumps or factories, would be associated with increased autism incidence, the researchers noted.

While autism clearly has a genetic component, the search for its cause has also turned up plenty of clues involving prenatal and early childhood environments, Hertz-Picciotto explained.

So her group applied a new cluster-detection technique to the addresses on birth certificates -- a location where late gestational or early neonatal exposures were likely to have occurred.

Among all 2.4 million children born from 1996 through 2000 in California, 9,900 had autism as recorded in the California Department of Developmental Services database through February 2006. The database is estimated to include 75 to 80 percent of all California children with the condition.

When cases and controls were analyzed by geographic location, clusters of elevated incidence emerged in eight of the 21 catchment areas of the state's developmental services regional centers.

Ten met stringent criteria, each with at least 70 percent greater risk than surrounding areas in seven different tests for clustering. Another two areas were potential clusters, according to lower criteria, with a positive result in at least four but not all seven tests.

These areas were:

The Golden Gate portion of San Francisco;

The area around Redwood City in the San Francisco Bay area;

The area around Sunnyvale and Santa Clara in the southern portion of the San Francisco Bay Area (Silicon Valley);

A small area around Modesto in the Central Valley of California;

The Fresno area, also in California's Central Valley;

The catchment area that includes Thousand Oaks in the Los Angeles region;

The area surrounding Beverly Hills;

The catchment area around Los Angeles that includes Norwalk and Cerritos;

The Los Angeles-region that includes Redondo Beach and Torrance;

The San Diego catchment area;

The Southern California catchment area that includes Dana Point and Mission Viejo.

Overall, these clusters have a parent population with higher educational levels. In six of the ten clusters, the likelihood of autism when a parent didn't finish high school was one-quarter of the likelihood when a parent graduated college.
Autism Lobby Unswayed By Vaccine Ruling

For three clusters, autism was less than half as likely when a parent had only some college education as when at least one parent had graduated from college.

Older parental age also had a small association, as did birth to Hispanic parents.

The researchers cautioned that they could not rule out environmental exposures related to higher parental education, such as genetic susceptibility or access to assisted reproduction or induced labor.

Nor did the study rule out environmental triggers entirely, Hertz-Picciotto noted.

"We'll continue to be searching for the environmental factors, but I don't think they're going to be sources of pollution in specific neighborhoods," she said in an interview. "We think that the kinds of environmental exposures that we need to look for are probably pretty broad."

---------------------------------------------------
Continuing Increases in Autism Reported to California’s Developmental Services System
Mercury in Retrograde
Robert Schechter, MD, MSc; Judith K. Grether, PhD
Arch Gen Psychiatry. 2008;65(1):19-24

Context: Previous analyses of autism client data reported to the California Department of Developmental Services (DDS) have been interpreted as supporting the hypothesis that autism is caused by exposure to the preservative thimerosal, which contains ethylmercury. The exclusion of thimerosal from childhood vaccines in the United States was accelerated from 1999 to 2001. The Immunization Safety Review Committee of the Institute of Medicine has recommended surveillance of trends in autism as exposure to thimerosal during early childhood has decreased.
Objective: To determine whether trends in DDS autism client data support the hypothesis that thimerosal exposure is a primary cause of autism. Design, Setting, and Patients: Study of time trends in the prevalence by age and birth cohort of children with autism who were active status clients of the DDS from January 1, 1995, through March 31, 2007.
Main Outcome Measure: Prevalence of autism among children with active status in the DDS.
Results: The estimated prevalence of autism for children at each year of age from 3 to 12 years increased throughout the study period. The estimated prevalence of DDS clients aged 3 to 5 years with autism increased for each quarter from January 1995 through March 2007. Since 2004, the absolute increase and the rate of increase in DDS clients aged 3 to 5 years with autism were higher than those in DDS clients of the same ages with any eligible condition including autism.
Conclusions: The DDS data do not show any recent decrease in autism in California despite the exclusion of more than trace levels of thimerosal from nearly all childhood vaccines. The DDS data do not support the hypothesis that exposure to thimerosal during childhood is a primary cause of autism.

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老婆心ながら、突然の失礼をお許しください。

本記事の結論が逆になっているのが気になりました。

In six of the ten clusters, the likelihood of autism when a parent didn't finish high school was one-quarter of the likelihood when a parent graduated college.

「10地域のうち6つでは、自閉症の割合は”両親が大卒の場合は未高卒の”1/4であった。」

ではなく、

「10地域のうち6つでは、自閉症の割合は”親が未高卒の場合は大卒場合の”1/4であった。」

自閉症の子どもの親は高学歴なことが多い、という説を検証している研究かと思われます。

なお、a parentなので、”両親” ではなく(どちらか片方の)”親”です。

ご存知のように、自閉症の要因については根拠のないものも含めていろいろ飛び交っており、誤解のないように情報を伝達する繊細さが求められます。お気をつけください。

失礼いたしました。
ある翻訳者
2010/01/14 22:42
導入段や、最後の文をみれば、高学歴との関連を示した記事であるのですが、大変失礼しました。
一分
2010/01/25 20:17

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自閉症増加は環境汚染ではなく親の学歴と関連/米国カリフォルニア 医師の一分/BIGLOBEウェブリブログ
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