Gut Bugs and Respiratory Illness in Children; Heat Illness and Homelessness

TTHealthWatch is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, director of electronic media for Johns Hopkins Medicine in Baltimore, and Rick Lange, MD, president of the Texas Tech University Health Sciences Center in El Paso, look at the top medical stories of the week.

This week’s topics include family affluence and telomeres in children, gut bugs and respiratory illness in children, heat illness and homelessness, and low potassium diets and hypertension and diabetes.

Program notes:

1:05 Heat illness and homelessness

2:05 No access to water

3:05 More likely in southern states

3:20 Telomere length, family affluence, and cortisol

4:20 High affluence had longer telomeres

5:20 Cortisol may need to be measured over longer time interval

6:20 Dietary patterns, sodium reduction, and hypertension in those with diabetes

7:20 Dash4D with low sodium

8:20 Low sodium is good

9:14 Neonatal gut microbiota and respiratory tract infections

10:14 Half of children born vaginally

11:15 First to look in newborns

12:39 End

Transcript:

Elizabeth: Does family affluence have anything to do with cortisol production and telomere length in children?

Rick: Modifying your diet to decrease blood pressure in people with diabetes.

Elizabeth: How do the gut bacteria that populate neonates impact on their susceptibility to lower respiratory tract infections?

Rick: And heat-related illness among U.S. individuals that experience homelessness.

Elizabeth: That’s what we’re talking about this week on TTHealthWatch, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I’m Elizabeth Tracey, a Baltimore-based medical journalist.

Rick: And I’m Rick Lange, president of Texas Tech University Health Sciences Center in El Paso, where I’m dean of the Paul L. Foster School of Medicine as well.

Elizabeth: Rick, since we’re all, and you there in El Paso told me before we started to record that it’s 102 degrees, let’s turn to JAMA Internal Medicine, this look at, oh, what happens if we have both extreme heat and homelessness.

Rick: Our listeners may not be aware that the year 2024 was the hottest year on record globally, and, in fact, it surpassed the record for the previous year in 2023. 2024 also set a record for the highest number of people experiencing homelessness in the United States on a single night. There are over 770,000, over three-quarters of a million people who experience homelessness. That was an increase of 18% over the prior year.

These authors used data from the largest all-payer emergency department database in the U.S. to examine heat-related illness among adults according to their housing status. And what they found is that when they looked at data from 2021 and 2022, people experiencing homelessness had 604 heat-related illnesses presenting in the emergency department per 100,000 population. This was 30-fold higher than the rate among all other U.S. adults. It was also more likely to require hospitalization.

Really alarming in terms of the magnitude of it. When they’re displaced, they don’t have access to air conditioning. They don’t have access to shaded parks sometimes. They don’t have access to water. Sometimes they’re on medications — diuretics, sometimes antipsychotics — that interfere with their ability to thermoregulate. But the magnitude of the problem is something we’ll need to address.

Elizabeth: Of course, we know that we have a housing crisis for many different populations. Was there any data in this study on the coincidence of mental illness along with homelessness?

Rick: This is most likely to occur in people under the age of 65, males three times more likely than females, individuals that had no insurance. If you had Medicaid, you were less likely than individuals with private insurance. And in the south part of the United States, three times more likely than experienced in the north. They did not have data regarding mental illness.

Elizabeth: I guess it’s not surprising that geographically there should be more of this in the south because if you’re homeless then you want to be in a climate that’s not going to be that severe for a lot of the year. Would that be a reasonable assertion, do you think?

Rick: It would be. So that they use the Northeast as the reference. People in the West about 50% more likely, people in the Midwest about two-fold more likely, and people in the South about three-fold more likely.

Elizabeth: Definitely sounds like a public health problem we need to think about.

Rick: We do.

Elizabeth: Let’s turn from here to The Lancet, this association of family affluence with cortisol production and telomere length, and this is in European kids.

They have a pretty large study that’s taking place in several countries in Europe called the Human Early Life Exposome project. In this study, they recruited 1,160 children, ages 5 to 12 years, who were a part of that study. And they defined several things in this population, what they called the family affluence scale, which is a validated scale that takes a look at, all right, how many assets does the family have. An index of psychosocial stress that they defined by total urinary cortisol production. And then they also looked at leukocyte telomere length. And we know that both of those things — cortisol and telomere length — have been associated in the past with certainly stress as far as cortisol is concerned, and telomere length has also been associated with one’s susceptibility to chronic disease and also with lifespan.

So what they found was that those kids who had a low family affluence scale, when they compared them with the kids who had the high family affluence scale, those kids with the high affluence had almost a 5% longer telomere length after adjustment for every other factor that they were looking at. With regard to this cortisol production, sort of unsurprisingly, that children of medium and high family affluence had significantly lower levels of cortisol production than those children who were in the lowest group. Cortisol production was not associated with telomere length.

Rick: They were trying to relate two different things, as you mentioned, lower socioeconomic status associated with smaller telomere length. It predicts lifespan. When they just looked at telomere length in this group of kids, it was short enough they predicted that their average lifespan would be 10 years shorter than the other group, and it also causes stress as well. So they’re trying to correlate the two. They were unable to do it in this particular study and it may be because that’s not the reason that the telomere length is shortened. Remember that they had just a couple cortisol measurements and that cortisol measurement, usually taken in a day, represents what’s happened within the last day. Sometimes you need to measure cortisol over a longer period of time and one of the ways to do that is to measure it in the hair.

On the other side, this was a great study. It was done in six different European countries, wide demographics, very well characterized as well. So there may be some truth to the fact that these things both occur, but one is not causing the other.

Elizabeth: It seems really obvious that what you do is you try to reduce stress and you try to create a baseline level of affluence that enables children to have a healthy upbringing. OK. What does this measurement actually tell us as far as actionable things?

Rick: Absolutely. And so if we want to assume that the shorter telomere length does lead or reflect shorter lives, and the thing that’s causing it is not stress and we need to figure out what else it is. And it may be due to other things, Elizabeth. It may be due to exposure to pollution. It could be due to changes in diet or poor nutrition. The importance is to getting at the underlying background.

Elizabeth: Right. So let’s move on to your next one, looking at dietary patterns, sodium reduction, and blood pressure in folks with type 2 diabetes, JAMA Internal Medicine.

Rick: It’s well known that diet can affect not only metabolic syndrome, but also hypertension, and probably the diet that’s best characterized for that is the DASH [Dietary Approaches to Stop Hypertension] diet. It’s a diet that is low in sodium, high in potassium, rich in vegetables and fruits, low in red meats, and low in saturated fats. Nobody has really looked at it in diabetics. Diabetics oftentimes have hypertension already, so they’re already on medications. Sometimes they have chronic kidney disease, so you don’t want them on a high-potassium diet. And the DASH diet doesn’t really regulate carbohydrates.

So what these authors did — let’s not use the DASH diet, but let’s use a modified DASH diet. We’re going to call it DASH4D, DASH for diabetics. We’re going to change it in the following ways. We’re not going to have a high potassium diet. We’re going to lower the carbohydrates a little bit and lower the saturated fats, and the rest of it pretty much stays the same. And we’re going to assess whether or not that can reduce blood pressure in diabetics already on medication. Let’s even take it a step further. Let’s do DASH4D with low sodium as well.

So that’s exactly what they did is they took 102 participants. They tested them on four different diets: a regular diet, what they were normally eating; a regular diet with low sodium; a DASH4D diet; and a DASH4D diet with low sodium.

Even in diabetics already on antihypertensive medications, if you put them on a DASH4D diet with low sodium, you could still reduce their blood pressure by about 4-5 mm Hg. That’s said to reduce your risk of stroke and heart disease by about 15%. The other diets — the DASH4D alone and the low sodium — they reduced it by about half as much.

Elizabeth: Let’s talk more about this particular diet. It sounds to me like, why not just put everybody on this? Let’s modify the DASH diet so that it already encompasses these other parameters because we already are looking with pretty close scrutiny at the role of sodium and hypertension.

Rick: I’m not sure that I would put everybody on the DASH for diabetics diet, unless they’re diabetic. Your point about a low-sodium diet, however, is very good. Overall, reducing sodium — and the DASH diet does that as well — is beneficial. A DASH-type diet, low sodium, is beneficial in the general population, and the specific modifications for diabetics is really helpful and safe in the diabetic population.

Elizabeth: OK, so when we’re talking about reducing potassium — we’ve already got these societal factors that are behind reducing sodium — how easy is it to reduce potassium, especially with regard to things like prepared foods?

Rick: Just as we identify food or food sources that are high in sodium, we can identify those that are high in potassium and just eliminate them from the diet. So that’s not very difficult at all. Prepared foods is a little bit more difficult, but as you know is this DASH diet doesn’t use a lot of prepared food. We’re talking about fresh vegetables, fresh fruits, really, no processed food.

Elizabeth: Sounds like a good choice to me.

Let’s turn then back to The Lancet and let’s look at this issue of neonatal gut microbiota and severe lower respiratory tract infections in the first 2 years of life. The number one cause of hospitalization among people, children younger than 2 years of age, is lower respiratory tract infection, and that’s normally viral.

So these folks are looking at whether the gut microbiota composition in neonates in the first week of life is associated with hospital admissions for that particular infection. They have this thing, the Baby Biome Study. Of course, this is done in the U.K. They were looking at stool collections in the first week of life and they used this shotgun-metagenomic sequencing to examine, well, what kind of bugs do you have in there? And then, of course, looking at hospital admissions in those first 2 years.

They had just over 1,000 children for whom they were able to successfully do this stool analysis and had the median follow-up of 2 years. About half of them were born vaginally and half of them by [cesarean section], and we know that there’s this colonization of children when they’re born vaginally that’s quite different from those that are born by [cesarean section].

Basically, they found that this higher first-week gut microbiota alpha diversity… OK, so what does that mean? I’ll say what it is in just a minute… was associated with reduced rates of hospitalization for this respiratory infection. They were able to identify three microbiotic clusters and the one that really seemed to be beneficial in terms of these infections had this species that’s called Bifidobacterium with a couple different types that were in there.

What do you do about that? I’m not exactly sure, but it’s really interesting to discern that, in fact, there are some gut bugs that appear to be protective.

Rick: Again, it’s really interesting. This is the first study that I’m aware of that looked at it basically in newborns. I mean, as you describe, babies are exposed to microbiota, either when they’re delivered vaginally or caesarean, and then over the course of the next several months to years their microbiota changes. And that’s a result of the environment, whether they’re breastfed or not.

When the babies are born, they initially have the antibodies/immune system transferred by their mother. Then over the next 3 to 6 months, that all goes away; they have to develop their own immune system. And it appears that the microbiota can affect that, something known as the gut-lung axis.

If we modulate the gut microbiota in the first months of life, could that prevent childhood respiratory infections? If it does need to be modified, does it need to be modified in the first week or the first month? It really does establish the gut microbiota as being an important part not just of the gut, but the entire immune system.

Elizabeth: We know this already from fecal transplant in adults and all multitude of places where people are attempting that to try to overcome chronic disease. I would be very concerned about actually populating a neonate with a certain population of bacteria I thought were going to end up being beneficial. I don’t even know what such a study would look like. No doubt we’re going to be hearing more.

On that note then, that’s a look at this week’s medical headlines from Texas Tech. I’m Elizabeth Tracey.

Rick: And I’m Rick Lange. Y’all listen up and make healthy choices.