電子たばこに、人を死に至らしめる危険性：米当局が調査を本格化
電子たばこを使用していた米国の男性が、呼吸器系の疾患を発症して死亡したことが明らかになった。電子たばことの関連性が確認されたか、もしくは疑われる肺疾患の患者は全米22州で193人に達しているといい、米当局は原因の究明に当たっている。
CDCは8月中旬から、食品医薬品局（FDA）および各州の保健当局と協力して原因の究明に当たっている。これはティーンエイジャーを含む若年層を中心に、呼吸困難や過度の疲労、体重の減少、胸部の痛みといった症例の報告が急増しているからだ。
193人の患者に共通しているのは、症状が始まる数カ月前から電子たばこを使用していたことで、ニコチンや大麻の有効成分であるテトラヒドロカンナビノール（THC）が含まれる製品を吸っていた人もいるという。患者の使っていた製品の銘柄などに統一性はなく、現段階では特定の成分が原因なのかは明らかになっていない。
CDCで喫煙と健康について研究しているブライアン・キングは、「電子たばこから出る蒸気が無害ではないことは知られています」と警告する。電子たばこのエアロゾルには鉛や発がん性のある化学物質の微粒子が含まれることが科学的に証明されており、CDCはこうした人体に害を及ぼす可能性のある物質のひとつが肺疾患を引き起こしたのかを調べている。
FDAのたばこ関連製品センターを率いるミッチ・ゼレールは、調査はまだ初期段階で、現在は各製品に含まれる化合物を特定しようとしているところだと話す。ゼレールは「それによって因果関係が必ずしも判明するわけではありませんが、パズルの重要なピースであることは確かです」と言う。
中高生の電子たばこ利用は10倍に
電子たばこが初めて登場したのは2007年のことだ。FDAはたばこ製品の管理権限をもつが、当時は電子たばこを規制する動きはなかった。一部のメーカーは、電子たばこは従来のたばこより健康のへの影響が少ない、または低リスクであるといった広告を打っていた。FDAは通常は、こうした宣伝文句が不適切でないかを製品の発売前に調査することになっている。ただ、電子たばこに限っては実施されなかった。
電子たばこの新製品は、現在では発売前にFDAの認可を受ける必要がある。だが、すでに市販されているものに関しては、FDAへの承認申請期限が2022年まで先送りされている。一方で、若者を中心に電子たばこの人気は高まるばかりだ。2011年から2015年までに、中学校と高校での電子たばこの喫煙者は10倍に拡大した。
ここ数年は伸びは緩やかにはなっているが、それでも上昇傾向が続いていることには変わりない。CDCの最新調査によると、2017年から18年の1年間で、高校での電子たばこ使用者は75パーセント増えており、いまでは高校生の5人に1人は電子たばこを吸っているという。公衆衛生局長官のジェローム・アダムスは、10代の若者の間で電子たばこの使用が急増している現状を「エピデミック」とまで呼んでいる。
まだ解明されていないことも多い
電子たばこは比較的新しい発明で、製品としての研究は進んでいない。ニコチンの悪影響は証明されており、なかでも身体と脳の発達段階では特によくないこともわかっている。しかし、ニコチン（含有量は製品によって異なる）、溶媒、フレーヴァーをつけるために用いられるさまざまな化学物質をまとめてエアロゾル化した場合に、人体にどのような影響を及ぼすのかは、まだ解明されていない。たばこの害を理解するまでに時間がかかったのと同じように、電子たばこの研究も簡単には進まないのだ。
一方、英国の公衆衛生庁の下部機関であるイングランド公衆衛生局は、電子たばこは通常のたばこと比べて安全性が95パーセント高いとの見解を示している。禁煙のための手段としては、ニコチンパッチやニコチンガムより効果が高いという研究結果もある。ただ、懸念される別の報告も徐々に出てきている。
具体的には、ニコチンを含まない電子たばこであっても血流に影響が生じるほか、喘息、肺気腫、脳卒中といった疾患のリスクが上がることが確認された。また、フレーヴァーなどに含まれる化学物質が不安定であることもわかっている。例えば、バターのような濃厚な風味をつけるための成分は、製造後しばらく時間が経つとほかの成分と化学反応を起こして有毒物質に変化してしまう。
さらに、製品そのものが新しいために、何十年といった単位で使用を続けた場合に何が起こるかは現段階では未知数だ。10代での使用により、年をとってから何らかの影響が出るのかもわからない。
電子たばこは過去10年以上にわたり、人々の健康に悪影響を与えてきた可能性がある。CDCが全国レヴェルでの調査に乗り出すのは今回が初めてだ。FDAは消費者に対し、電子たばこに関連する健康上の問題を抱えている場合は詳細を報告するよう呼びかけている
Vaping May Have Killed Someone, Health Officials Say
An
investigation into respiratory illnesses connected to e-cigs by the
Centers for Disease Control and Prevention turned up the first known
death this week.
Sometime
between Wednesday and Friday, an Illinois resident died of an unknown
respiratory illness that may have been the result of vaping.
The death was one of nearly 200 cases of mysterious respiratory
problems across 22 states whose only known link is the recent use of
electronic cigarettes, or vapes, according to the Centers for Disease
Control and Prevention.
The CDC, a federal agency, is now working with state health agencies and the Food and Drug Administration to try and find the cause, part of an investigation launched in mid-August after dozens of people, mostly teenagers and young adults, started showing up in hospitals reporting symptoms including difficulty breathing, fatigue, weight loss, and chest pain. That population has increased to 193 cases, all of whom had vaped in the month prior to their illness. Some were smoking nicotine, others THC or cannabinoids. The victims used different products, and no one ingredient stood out as a potential culprit.
“We do know that e-cigarettes do not emit a harmless aerosol,” says Brian King of the CDC’s Office on Smoking and Health. Scientists have already identified a variety of ingredients in e-cigarettes as dangerous, including particulates that contain lead, chemicals that cause cancer, and toxic flavorings. The CDC is now working to identify whether one of these potentially “problematic” agents is to blame for the current outbreak.
The investigation is still in the early stages. Mitch Zeller, director of the FDA’s Center for Tobacco Products, says the FDA is trying to identify the compounds in each product. “That won’t necessarily determine causality, but it's an important piece of the puzzle,” he says.
When e-cigarettes first came on the market in 2007, the FDA didn't move to regulate them, even though the Tobacco Control Act gives the administration the authority. Some e-cigarette makers advertised their products as being low-risk or less harmful than regular cigarettes, which are the kinds of claims the FDA is supposed to assess during "premarket reviews" before something goes on sale.
That didn't happen here. Today, any new e-cig products have to be approved before they go on sale. But for products already out there, the deadline for submitting applications for FDA review has been pushed back to 2022.
In the meantime, vaping has become a hugely popular habit, particularly among teenagers. Between 2011 and 2015, vaping among middle schoolers and high schoolers shot up 900 percent. The growth has slowed, but continues to trend upward. From 2017 to 2018, rates of high school vaping increased by more than 75 percent. According to the CDC’s most recent studies, nearly one in five high schoolers vapes. The US surgeon general has called the ubiquity of teenage vaping an epidemic.
One of the challenges facing antivaping advocates is that science progresses slowly, and e-cigarettes can be difficult to study. Nicotine is bad for you, and it's especially bad for young people whose bodies and brains are still developing. But less clear is how these new vaporizing mechanisms—all of which use different nicotine doses, different solvents, different heating mechanisms, and sometimes different flavoring ingredients—affect humans. Untangling the effects of each component takes time, just as it did when scientists first studied the effects of regular cigarettes.
Public Health England, a UK government agency, has said e-cigarettes are 95 percent safer than regular, combustible cigarettes, and one study did show that e-cigarettes are more effective than nicotine replacement patches or gums at getting people to quit. But a growing body of scientific evidence paints a darker picture.
The CDC, a federal agency, is now working with state health agencies and the Food and Drug Administration to try and find the cause, part of an investigation launched in mid-August after dozens of people, mostly teenagers and young adults, started showing up in hospitals reporting symptoms including difficulty breathing, fatigue, weight loss, and chest pain. That population has increased to 193 cases, all of whom had vaped in the month prior to their illness. Some were smoking nicotine, others THC or cannabinoids. The victims used different products, and no one ingredient stood out as a potential culprit.
“We do know that e-cigarettes do not emit a harmless aerosol,” says Brian King of the CDC’s Office on Smoking and Health. Scientists have already identified a variety of ingredients in e-cigarettes as dangerous, including particulates that contain lead, chemicals that cause cancer, and toxic flavorings. The CDC is now working to identify whether one of these potentially “problematic” agents is to blame for the current outbreak.
The investigation is still in the early stages. Mitch Zeller, director of the FDA’s Center for Tobacco Products, says the FDA is trying to identify the compounds in each product. “That won’t necessarily determine causality, but it's an important piece of the puzzle,” he says.
When e-cigarettes first came on the market in 2007, the FDA didn't move to regulate them, even though the Tobacco Control Act gives the administration the authority. Some e-cigarette makers advertised their products as being low-risk or less harmful than regular cigarettes, which are the kinds of claims the FDA is supposed to assess during "premarket reviews" before something goes on sale.
That didn't happen here. Today, any new e-cig products have to be approved before they go on sale. But for products already out there, the deadline for submitting applications for FDA review has been pushed back to 2022.
In the meantime, vaping has become a hugely popular habit, particularly among teenagers. Between 2011 and 2015, vaping among middle schoolers and high schoolers shot up 900 percent. The growth has slowed, but continues to trend upward. From 2017 to 2018, rates of high school vaping increased by more than 75 percent. According to the CDC’s most recent studies, nearly one in five high schoolers vapes. The US surgeon general has called the ubiquity of teenage vaping an epidemic.
One of the challenges facing antivaping advocates is that science progresses slowly, and e-cigarettes can be difficult to study. Nicotine is bad for you, and it's especially bad for young people whose bodies and brains are still developing. But less clear is how these new vaporizing mechanisms—all of which use different nicotine doses, different solvents, different heating mechanisms, and sometimes different flavoring ingredients—affect humans. Untangling the effects of each component takes time, just as it did when scientists first studied the effects of regular cigarettes.
Public Health England, a UK government agency, has said e-cigarettes are 95 percent safer than regular, combustible cigarettes, and one study did show that e-cigarettes are more effective than nicotine replacement patches or gums at getting people to quit. But a growing body of scientific evidence paints a darker picture.
Still, scientists have many outstanding questions. Because the products are relatively new, the long-term effects of extended vaping remain unknown, as do the specifics of how they might affect growing teenage bodies.
Vaping may have been causing respiratory illnesses for years, but the CDC’s investigation is the first attempt to collect, aggregate, and analyze national data. The FDA encourages anyone who has had a health problem related to e-cigarettes to file a detailed report at www.safetyreporting.hhs.gov.
TEXT BY SARA HARRISON
TRANSLATION BY CHIHIRO OKA
WIRED(US)
TRANSLATION BY CHIHIRO OKA
WIRED(US)
