真是掃興 (Buzz Kill):吸食大麻煙客的肺損傷看起來更嚴重
資料來源:Donavyn Coffey / 2022 年 11 月 15 日 / Medscape / 財團法人台灣紅絲帶基金會編譯
大麻吸食者的肺部掃描結果令人震驚:經常吸食大麻的人患肺部損傷的風險似乎比僅吸食菸草的人更大。
吉賽爾.雷瓦博士;圖片來源:Tetra Images/Getty Images
「公眾認為大麻是安全的」,加拿大安大略省渥太華大學放射科醫生、醫學博士 Giselle Revah 說。 「這項研究引起了人們的擔憂,即上述看法可能不是真的」。
Revah 說她通常可以立即判斷 CT 掃描是來自重度吸菸者還是長期吸菸者。但隨著大麻在加拿大和美國許多州的合法化和使用的增加,她開始想知道使用大麻對肺部有什麼影響,以及她是否能夠將其影響與吸煙的影響區分開來。
她和她的同事回顧性檢查了 56 名吸食大麻者的胸部 CT 掃描結果,並將其與 57 名非吸煙者和 33 名僅吸食大麻者的掃描結果進行了比較。
肺氣腫在吸食大麻者 (75%) 中比在非吸食者 (5%) 中更常見。當匹配年齡和性別時,吸食大麻的人中有 93% 患有肺氣腫,而僅吸食菸草的人中有 67% 患有肺氣腫 (P = .009)。
在沒有年齡匹配的情況下,大麻使用者的肺氣腫發病率仍然略高(75% 對 67%),儘管差異不再具有統計學意義。然而,超過 40% 的大麻吸食者係年齡在 50 歲以下,而所有吸菸的人都在 50 歲或以上——這意味著吸食大麻的人可能會更早或接觸更少大麻即出現肺損傷,Revah 說。
Revah 補充說,她在家庭醫學領域的同事表示,這些發現與他們的臨床經驗相符。「在他們的實務中,他們有年輕的肺氣腫患者」,她說。
研究人員發現,吸食大麻的人還表現出較高的氣道炎症發生率,包括支氣管增厚、支氣管擴張和粘液嵌塞,無論性別和年齡是否進行匹配。
安大略省一位在呼吸系統健康方面具有專業知識的家庭醫生、醫學博士艾倫·卡普蘭 (Alan Kaplan) 表示,這些發現「一點也不令人驚訝」。他是 2021 年關於大麻和肺部健康的評論的作者。
在該期刊文章的一篇社論中,肺科專家指出,新數據為近期非創傷性氣胸轉診增加提供了背景。作者說,他們在過去 2 年中收到了 22 例此類轉診,但在 2012 年至 2020 年期間他們只收到了 6 例。
卡普蘭說,造成額外損害的原因之一可能是吸入大麻的方式。吸食大麻的人「深吸一口氣,他們真的把它推入肺部並對其施加壓力,這實際上可能會導致肺泡隨著時間的推移而擴張」。
Revah 說,由於研究中的大多數吸食大麻的人也吸香菸,因此無法辨別觀察到的損害是由大麻單獨造成的,還是透過與菸草的協同作用造成的。
儘管如此,她說,結果仍然令人震驚,因為在此係將吸食大麻的人群與具有廣泛吸菸史(25 至 100 包年)且來自高風險的肺癌篩查計畫之菸草使用者進行了比較。
Revah 和她的同事現在正在進行一項更大規模的前瞻性研究,看看他們是否能證實他們的發現。
「給醫生的信息是去詢問吸食大麻的情況」,卡普蘭說。過去,人們一直不願承認使用大麻。即使合法化,他們也可能不會告訴他們的醫生。但臨床醫生仍應嘗試識別頻繁使用者,尤其是那些易患肺部疾病的使用者。如果他們打算使用這種藥物,給他們建議應該是,「有更安全的方法來使用大麻」,他說。
Revah 和 Kaplan 沒有披露相關的財務關係。
《放射學》。 2022 年 15 日線上發布。社論,全文。
Donavyn Coffey 是肯塔基州的一名記者,報導醫療保健、環境以及任何影響我們飲食方式的事物。她擁有紐約大學 Arthur L. Carter 新聞學院的碩士學位和丹麥奧胡斯大學的分子營養學碩士學位。您可以在《連線》、《科學美國人》、《大眾科學》和其他地方看到她的更多作品。
Medscape 醫學新聞 © 2022;引用:Buzz Kill:吸食大麻的人肺部損傷看起來更嚴重 – Medscape – 2022 年 11 月 15 日。
Buzz Kill: Lung Damage Looks Worse in Pot Smokers
Donavyn Coffey / November 15, 2022 / Medscape
Scans of the lungs of pot users have turned up an alarming surprise: Regular smokers of marijuana appear to be at greater risk for lung damage than are people who smoke tobacco alone.
Dr Giselle Revah
“There’s a public perception that marijuana is safe,” said Giselle Revah, MD, a radiologist at the University of Ottawa, Ontario, Canada. “This study is raising concern that this might not be true.”
Revah said she can often tell immediately if a CT scan is from a heavy or long-time cigarette smoker. But with the legalization and increased use of marijuana in Canada and many US states, she began to wonder what cannabis use does to the lungs and whether she would be able to differentiate its effects from those of cigarette smoking.
She and her colleagues retrospectively examined chest CT scans from 56 marijuana smokers and compared them to scans of 57 nonsmokers and 33 users of tobacco alone.
Emphysema was significantly more common among marijuana smokers (75%) than among nonsmokers (5%). When matched for age and sex, 93% of marijuana smokers had emphysema, vs 67% of those who smoked tobacco only (P = .009).
Without age matching, rates of emphysema remained slightly higher among the marijuana users (75% vs 67%), although the difference was no longer statistically significant. Yet more than 40% of the marijuana group was younger than 50 years, and all of the tobacco-only users were 50 or older ― meaning that marijuana smokers may develop lung damage earlier or with less exposure, Revah said.
Revah added that her colleagues in family medicine have said the findings match their clinical experience. “In their practices, they have younger patients with emphysema,” she said.
Marijuana smokers also showed higher rates of airway inflammation, including bronchial thickening, bronchiectasis, and mucoid impaction, with and without sex- and age-matching, the researchers found.
The findings are “not even a little bit surprising,” according to Alan Kaplan, MD, a family physician in Ontario who has expertise in respiratory health. He is the author of a 2021 review on cannabis and lung health.
In an editorial accompanying the journal article, pulmonary experts note that the new data give context to a recent uptick in referrals for nontraumatic pneumothorax. The authors say they have received 22 of these referrals during the past 2 years but that they had received only six between 2012 and 2020. “Many, but not all, of these patients have a documented history of marijuana use,” they write.
One reason for the additional damage may be the way marijuana is inhaled, Kaplan said. Marijuana smokers “take a big breath in, and they really push it into lungs and hold pressure on it, which may actually cause alveoli to distend over time.”
Because most marijuana smokers in the study also smoked cigarettes, whether the observed damage was caused by marijuana alone or occurred through a synergy with tobacco is impossible to discern, Revah said.
Still, the results are striking, she said, because the marijuana group was compared to tobacco users who had an extensive smoking history ― 25 to 100 pack-years ― and who were from a high-risk lung cancer screening program.
Revah and her colleagues are now conducting a larger, prospective study to see whether they can confirm their findings.
“The message to physicians is to ask about cannabis smoking,” Kaplan said. In the past, people have been reluctant to admit using cannabis. Even with legalization, they may be slow to tell their physicians. But clinicians should still try to identify frequent users, especially those who are predisposed for lung conditions. If they intend to use the drug, the advice should be, “There are safer ways to use cannabis,” he said.
Revah and Kaplan have disclosed no relevant financial relationships.
Radiology. Published online 15, 2022. Full text, Editorial
Donavyn Coffey is a Kentucky-based journalist reporting on healthcare, the environment, and anything that affects the way we eat. She has a master’s degree from NYU’s Arthur L. Carter Journalism Institute and a master’s in molecular nutrition from Aarhus University in Denmark. You can see more of her work in Wired, Scientific American, Popular Science, and elsewhere.
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Cite this: Buzz Kill: Lung Damage Looks Worse in Pot Smokers – Medscape – Nov 15, 2022.