October 31, 2019

Burgers or air?

Q: Did you see that asthma inhalers cause as much greenhouse gas emission as eating meat?

A: Yes

Q: That’s huge!! It’s like 15% of global warming!

A: No

Q: Yes!

A: No. The BBC claim is that the CO2 equivalent of one person‘s use of asthma inhalers is comparable to one person‘s meat consumption. A lot more people eat meat than use asthma inhalers.

Q: Oh. That’s still quite a lot, though?

A: They say it’s about 4% of emissions from the UK healthcare system. About 0.15% of the UK total.

Q: And compared to meat?

A: Well, the BBC don’t link, but if you find the research paper (PDF) and follow its link for the meat claim, you get a graph saying about 0.9 tonnes CO2 equivalent per year for an average person switching to a plant-based diet in the UK, compared to the 165kg average they’re claiming for the inhalers (range of 150-400kg).

Q: Isn’t 165kg less than 0.9 tonnes?

A: Yes, quite a bit less.

Q: So why do they get away with that in a published research paper?

A: It’s not the point of the paper. The point is to look at the financial cost of the National Health System switching to asthma inhalers that don’t use greenhouse gases, for the subset of people who can use them.  The costs aren’t that bad. They also suggest other sensible ways to reduce emissions, such as recycling or incinerating used inhalers, and labelling them with the number of doses so that they don’t get discarded early.

Q: What are we doing about this in New Zealand?

A: A bit more than for meat.  There’s an actual plan to reduce total imports of these synthetic greenhouse gases starting now and going through 2036, but in the short term that’s mostly going to affect air conditioners, not inhalers. Pharmac asked for bids for asthma inhaler supply through 2023, and (earlier this month) proposed settling on two products with HFC-134a propellant, which is the less-bad of the two greenhouse gases currently used in inhalers. 

Q: If the point is financial costs, isn’t the comparison with meat just trolling?

A: Pretty much.  Eating plants is an individual choice, it’s not an all-or-nothing change, it doesn’t take a doctor’s prescription, and you don’t need to have asthma to do it.  You could just decide to eat less meat, or give up beef, or your whole household could eat less  meat. And eating less meat doesn’t have negative health implications.

Q: So people should just use their inhalers like their doctor says?

A: Absolutely.  Modern preventer inhalers are a major achievement of medical and chemical science.  For any individual, there should be many possible lifestyle changes higher up your priority list than worrying about your model of asthma inhaler.  Maybe get ready to lobby Pharmac to take emissions into account when they next put out a bid for inhalers,  in 2022 or thereabouts.

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »

Comments

  • avatar
    Brett Montgomery

    Hi Thomas. Thanks for your commitment to statistical literacy — I enjoy your website.

    I’m a GP in Australia with an interest in this asthma/climate change topic. I agree with you that inhaler gases are less important contributors to individual carbon footprints than things like diet and transport. But they are not negligible.

    For many people, dry powder inhalers can be equally as effective as metered dose inhalers. (Evidence: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC58536/ ) (Important exceptions include young children, people with limited inspiratory capacity, and people who would struggle to learn how to use a new inhaler device.)

    Living on the other side of the Tasman, I confess to not completely understanding the PHARMAC system, but I think you may be wrong to imply that they have defunded dry powder inhalers. This seems true, as per your link, for fluticasone-containing inhalers. But there are other dry powder steroid and combination inhalers which are for most people clinically equivalent. Some seem funded by PHARMAC; see https://www.pharmac.govt.nz/news/notification-2016-02-03-budesonide-eformoterol/ or https://www.pharmac.govt.nz/wwwtrs/ScheduleOnline.php?osq=Pulmicort or https://www.pharmac.govt.nz/wwwtrs/ScheduleOnline.php?osq=Symbicort for example.

    I don’t want anyone to feel so guilty about their asthma medicine that they fail to take what they need. But if there are products that are greener, and equally useful for asthma, why not try them? As an asthmatic GP who has stopped eating meat and flying in planes, and still wants to do more, it has been empowering for me to discover this possibility for further action. While our politicians dither on climate action, this is one thing I can do now.

    5 years ago