Ep 135: Elderly Couple Considering Home Renovations

In this episode, we discuss the impact of ambient and household air pollutants, which may significantly affect respiratory and cardiac health.

See more on this topic on AccessMedicine.

Transcript

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[Ms. Heidhausen] This is Katarina Heidhausen, executive editor of Harrison's Principles of Internal Medicine. Harrison's Podclass is brought to you by McGraw Hill's AccessMedicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, on to the episode. 

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[Dr. Handy] Hi everyone. Welcome back to Harrison's Podclass. We're your co-hosts. I'm Dr. Cathy Handy. 

[Dr. Wiener] And I'm Dr. Charlie Wiener, and we're joining you from the John Hopkins School of Medicine. 

[Dr. Handy] Welcome to episode 135: an elderly couple considering home renovations. 

[Dr. Wiener] Hey, Cathy. Well, today's case is very contemporary. 

[Dr. Handy] I can tell. 

[Dr. Wiener] So your 74-year-old patient and her daughter come to the clinic today asking for your advice. Your patient and her 75-year-old husband are remodeling their house and they want to put in a new gas range. Their daughter, an environmental activist, is adamant against that idea because she says that gas ranges are not healthy for her mother and her father, and she wants them to get the more expensive induction cooktop. 

[Dr. Handy] Well, let's talk about their medical history first. 

[Dr. Wiener] Well, your patient has a history of reactive airway disease, coronary artery disease, and peptic ulcer disease. Her husband was a smoker that worked in the coal mines, and he has moderate COPD. I'm going to jump right to the question. The question is asking, compared with an induction stove, a gas stove is associated with a higher severity of all the following disorders except? A. acute MI; B. asthma; C. COPD; D. pneumonia; or E. venous thromboembolism. 

[Dr.Handy] Well, this is a little bit of a trick question, but let's start with some terminology and background. One of the keys is to understand the term PM2.5, which stands for a particulate matter that is less than 2.5 microns. These are the particles that when inhaled, do not get trapped in the nose or large airways, but travel down to the lung parenchyma. While we often talk about the gaseous air pollutants such as ozone, sulfur dioxide, or nitrogen dioxide, these fine particulate matter particles have strong associations with a variety of respiratory and cardiovascular illnesses. 

[Dr. Wiener] Where do these PM2.5 particles come from? 

[Dr. Handy] The major source of the particles is burning fossil fuels. They are also produced by wildfires, which we all know have been increasing with climate change. And the health effects of these particles is not just a function of ambient air pollution, but as illustrated in this case, household air pollution. There are many parts of the world that still rely heavily on indoor fire or coal-burning stoves which produce large amounts of air pollutants with high exposures to the people living inside. In 2016, exposure to ambient air pollution, indoor household air pollution was estimated to cause 7.1 million premature deaths worldwide per year. So this is a huge issue. 

[Dr. Wiener] Okay, well, let's get to the issues here. First, do gas stoves present any potential health effects when compared to induction or electric cooktops? 

[Dr. Handy] Yes. So since gas stoves burn hydrocarbons, they produce fine particulate particles. They also produce measurable amounts of nitrogen dioxide, carbon monoxide, and benzene. In fact, California is contemplating a state law requiring a health warning label on gas stoves. And, as you would imagine, the worse your ventilation, the higher the exposure. 

[Dr. Wiener] Okay. Well, we've established that gas stoves have a higher health risk than electric, but the question asks about a bunch of specific disorders. 

[Dr. Handy] Yes, and it is a trick question because PM2.5s are associated with a higher risk of all the options. 

[Dr. Wiener] Really? Tell me more. 

[Dr. Handy] Well, first, from a respiratory standpoint, increasing levels of PM2.5 and ozone are associated with increasing severity of asthma, the respiratory effects of allergies, rhinosinusitis, COPD, respiratory tract infections, interstitial lung disease, and lung cancer. They are also implicated in increased hospital admissions and premature death. The particles have been shown to affect lung innate and adaptive immunity, as well as increase oxidative stress. 

[Dr. Wiener] What about cardiovascular disease? 

[Dr. Handy] Cardiovascular complications of climate change share similar mechanisms with climate-sensitive respiratory disease. Concentrations of PM2.5 are the most important environmental risk factor for myocardial infarction, cerebrovascular disease, heart failure, hypertension, diabetes, arrhythmias, and venous thromboembolism. 

[Dr. Wiener] Wow. That covers the entire spectrum. Are these risks short-term or long-term? 

[Dr. Handy] Both. Studies have shown that the relative risk of acute cardiovascular events is increased 1 to 3% in the setting of short-term elevations of PM2.5. Longer-term exposures convey about a 10% increased risk, which is partially attributable to the exacerbation of chronic conditions such as hypertension and diabetes. 

[Dr. Wiener] Wow. I assume the mechanisms are similar to the respiratory tract? 

[Dr. Handy] Yes, it's likely that oxidative stress and inflammation are common pathways. 

[Dr. Wiener] Well, you filled us with bad news today. Any more bad news? 

[Dr. Handy] Of course. A systematic review of studies across diverse U.S. populations found a statistically significant association of PM2.5, ozone, and heat exposure with preterm birth, low birth weight at term, and stillbirth. As these environmental exposures become more common with climate change, an increased incidence of these complications is very possible. 

[Dr. Wiener] Okay. Well, the teaching points of today's episode and possibly, future episodes, is that we are living in a changing environment, and this will have a huge impact on health. Fine particulate matter less than 2.5 microns or PM2.5, is associated with the worsening of multiple cardiopulmonary conditions. 

[Dr. Handy] If you liked this episode, you can find this question and others like it on Harrison's Self-Review, and you can read more about it in the Harrison's chapter on the health effects of climate change. Visit the show notes for links to helpful resources, including related chapters and review questions from Harrison's, available exclusively on AccessMedicine. If you enjoyed this episode, please leave us a review, so we can reach more listeners just like you. Thanks so much for listening. 

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