電子たばこも無害ではない、心臓血管系に影響　米大研究

【パリＡＦＰ＝時事】10代の間で特に人気のある電子たばこや、その呼出煙（口から吐いた煙）に含まれる化学物質が心臓血管系に害を及ぼす恐れがあると警鐘を鳴らす論文が、7日付の欧州心臓病学会誌「Cardiovascular　Research」に掲載された。電子たばこをめぐっては、これに関連するとみられる健康被害や死亡例が報告されており、懸念を指摘する声が高まっている。（写真は資料写真）
　米オハイオ州立大学のローレン・ウォルド氏は論文の中で、「電子たばこには無害な水蒸気の他に、ニコチンや微粒子状物質、金属物質、香味料が含まれている」と指摘。「大気汚染に関する研究によって、（空気中の）微粒子は循環血液に入り込んで直接、心臓に影響を及ぼすことが証明されている。電子たばこに関するデータも同じ方向を示している」と述べている。従来のたばこにも含まれるニコチンは、血圧や心拍数を上昇させることが知られている。
　このほかにも電子たばこには、「ヒトに対して発がん性がある」と分類され、ラットを用いた研究で心臓障害を引き起こしたホルムアルデヒドが含まれている。
　さらに、ミントやキャンディー、フルーツなどの香味料については、健康被害をもたらす可能性の有無がほとんど分かっていない。
　オハイオ州立大チームの論文は、「一般的に口から吸いこんでも無害と考えられがちな電子たばこだが、電子たばこを吸引することによる体形的な影響はほとんど知られていない」と指摘している。
　ウォルド氏によれば、これまでの電子たばこに関する研究は、ほとんどが常習によるリスクよりも急性リスクに集中しているという。
　さらに受動吸引や、壁やカーテン、衣服に付着した粒子の健康への影響も、ほとんど不明なままだ。
　米疾病対策センターによると、１０月２９日までに米国の２４州で、電子たばこの影響とみられる死亡例が３７件報告されている。さらに肺障害例は全米で１９００件近くに上る。
　世界保健機関（ＷＨＯ）によれば、世界における電子たばこの使用者は２０１１年の７００万人から、２０１８年には４１００万人に急増している。電子たばこはデザイン性が高いこともあり、特に若い世代にとって魅力的なものとなっているという。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2019/11/11-08:39）

Vaping devices and the chemicals they deliver -- increasingly popular among teens -- may damage the cardiovascular system, a study said Thursday, adding to a growing chorus of concern over injury and deaths related to e-cigarettes.
The latest findings, published in the journal Cardiovascular Research, come after the US Centers for Disease Control and Prevention last month declared an outbreak of lung injuries linked to vaping.
E-cigarettes contain nicotine, particulate matter, metal and flavourings, not just harmless water vapour, senior author Loren Wold of Ohio State University wrote in Thursday's study.
Air pollution studies show that fine particles enter the circulation and have direct effects on the heart -- data for e-cigarettes are pointing in that direction.
Nicotine, also found in tobacco, is known to increase blood pressure and the heart rate.
But other ingredients inhaled through the vaping may lead to inflammation, oxidative stress and unstable blood flow, Wold said.
Ultrafine particulate, for example, has been linked to thrombosis, coronary heart disease and hypertension, among other conditions.
E-cigarettes also contain formaldehyde, which has been classified as a cancer-causing agent and associated with heart damage in experiments with rats.
Moreover, almost nothing is known about the potential health hazards of flavouring agents that mimic the taste of mint, candy or fruits such as mango or cherry, the study noted.
While most are deemed safe when ingested orally, little is known of their systemic effects following inhalation, the researchers wrote.
To assess possible impacts on the heart and vascular system, Wold and colleagues undertook a systematic review of medical literature, which remains thin due to the newness of e-cigarette use.
- Teens 'not getting the message' -
Wold noted that most studies to date have focused on the acute effects of e-cigarette use rather than the risk of chronic use.
Also, little is known about the secondhand effects of vaping, as well as exposure to particles lodged in walls, drapes and clothing.
Thirty-seven deaths in 24 states have been linked to e-cigarette and vaping products as of October 29, according to the CDC. There were nearly 1,900 cases of associated lung injury nationwide.
In the majority of cases, persons affected also used the devices to consume products containing THC, the psychoactive ingredient in cannabis, raising the possibility that unknown impurities were also present.
The CDC discourages non-smokers from starting to use e-cigarettes and suggests individuals trying to kick a tobacco habit use alternatives approved by the US Food and Drug Administration (FDA), such as patches and gums.
But the popularity of vaping has skyrocketed since the devices were introduced to the US and European markets just over a decade ago.
Vaping users increased from seven million worldwide in 2011 to 41 million in 2018, according to the World Health Organization (WHO).
The products are particularly appealing to young users -- often by design, according to critics.
One in four high school students in the United States uses e-cigarettes, up more than 15 percent from two years ago, according to the 2019 National Youth Tobacco Study.
Use by preteens doubled from 2018 to 2019, with 10 percent of middle school students admitted to vaping.
Adults are beginning to get the message that the full health effects of vaping are unknown, and the risk is potentially very high, said Wold.
My fear is that has not been crystallised in adolescents.