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 surveying London sewage for polio, physical activity and COVID vaccines, diet changes and mortality, and maternal hypertension and offspring mortality.
Program notes:
0:37 Physical activity and COVID vaccination
1:37 High activity 86% effective
2:37 Quarantine and isolation?
3:00 Detection of poliovirus in sewage
4:01 Total of 118 genetically linked isolates found
5:01 Surveillance tool powerful
6:01 Identify specific genotypes
6:30 Changes in diet and mortality
7:30 Improvement of 13-33%
8:32 Two groups included
9:30 Maternal hypertension and offspring mortality
10:31 Eclampsia associated with highest mortality
11:31 Doesn’t show that treatment prevents death
13:00 End
Transcript:
Elizabeth: Maternal high blood pressure and impact on offspring.
Rick: Changes in diet quality and its association with mortality.
Elizabeth: Surveying for poliovirus in London sewage.
Rick: And does physical activity influence the effectiveness of the COVID vaccine?
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: I’m Rick Lange, president of Texas Tech University Health Sciences Center in El Paso, where I’m also the dean of the Paul L. Foster School of Medicine.
Elizabeth: Of course, we are going to start with the COVID materials. Let’s turn right to the British Journal of Sports Medicine, one more benefit of physical activity with regard to COVID.
Rick: Previous studies have shown that both vaccination and physical activity independently decrease the likelihood of having a severe COVID-19 infection. Do the two together influence the effectiveness of the COVID vaccine? Specifically, when we talk about the effectiveness, we are talking about being hospitalized for severe COVID disease.
These investigators attempted to answer that by looking at individuals who are unvaccinated compared with those who were fully vaccinated with one of the adenovirus vaccines. Then these individuals also identified whether they were involved with different levels of physical activity — either low, medium, or high amounts of physical activity — to test the effect of whether physical activity could modify the effectiveness of COVID vaccine.
Here is what they found out: The vaccine in fact was effective, but in those that had the vaccine and low physical activity the effectiveness was about 60%. For the moderate group, it was 72% and for those with high amounts of physical activity it was 86%.
Elizabeth: Clearly, one of the things I would be interested in as a recipient of mRNA vaccines is I wonder what this data would show relative to those.
Rick: Yep. It’s limited, as you mentioned, and to a particular adenovirus vaccine. I would submit to you that it’s probably independent of the vaccine and it’s more related to how physical activity modifies our immune response. We know that people that have more physical activity independent of vaccination have better immune systems, are more able to fight infections, and are less likely to have serious infections. You could extend that in saying even in vaccinated individuals the amount of physical activity could modify the effectiveness and the immune response as well.
Elizabeth: Then can we extend that to things like responses to the flu vaccine, for example, if it’s the modifying effect of physical activity?
Rick: Well, in fact, that’s part of the basis of this study. Studies have shown that physical activity does influence the effectiveness of flu vaccine as well. Where the rubber hits the road on this is we had a lot of people in quarantine or isolation in the setting of severe infections with COVID. We oftentimes do that with influenza as well. That means we need to find alternative ways of still being physically active despite being socially distanced at the same time.
Elizabeth: Not to mention all the other benefits of exercise. Of course, we are preaching to the choir here.
Let’s turn to The Lancet since we’re talking about viruses and let’s talk about detection of type 2 poliovirus in London sewage between February and July of this year. They’re using enhanced environmental surveillance to look at this particular issue.
We know, of course, that there is an international spread of poliovirus and it exposes everybody everywhere to the risk of outbreaks. It has been designated a public health emergency of international concern by the WHO [World Health Organization]. This risk, of course, is exacerbated in countries that use an inactivated polio vaccine. That’s a great vaccine if you’re protecting against paralysis, but it’s less effective than the oral vaccine against shedding the virus, therefore reducing the potential for people to infect each other.
This study is taking a look at the molecular properties of type 2 poliovirus isolates found in London sewage, trying to detect how much virus transmission is taking place in this community using sewage samples gathered with WHO-recommended methods.
Here is what they found: 118 genetically linked poliovirus isolates related to the serotype 2 Sabin vaccine strain. Those were detected in 21 of 52 sequential sewage samples. All isolates had lost two key attenuating mutations, which is concerning, and were recombinant with a species C enterovirus.
They also found other changes in these viruses. They argue that their methods definitely indicate that we ought to be doing enhanced surveillance of all kinds of viruses, of course, not just poliovirus.
Rick: Elizabeth, I have to say that about a year ago when people talked about monitoring COVID infection using sewage samples I didn’t quite get it at the time. In this particular case, these are the first evidence of polio transmission in the United Kingdom since 1984. None of these patients have symptoms, by the way. You’re talking about identifying a virus in asymptomatic individuals. As you mentioned, the potential of passing this on to individuals that have not been vaccinated means that we could have a recurrence of polio, which we thought we have otherwise eradicated.
This environmental surveillance tool is really pretty powerful. That they can go to specific water treatment areas to find out in which borough it is and therefore target that borough for making sure that children under the age of 9 are clearly vaccinated, because they are the ones that are most susceptible — i.e., children that are not vaccinated.
Elizabeth: They do note, of course, in the conclusion that based on this they reintroduced that vaccination policy in kids in London. It sounds to me like maybe we ought to be thinking about this as absolutely routine surveillance and then be poised to reactivate vaccine campaigns as soon as we detect it.
Rick: That’s exactly what happened here. Again, they have not had a detected case since 1984 and it’s because of the active surveillance program. It’s not only collecting sewage, but being able to analyze it very quickly and very specifically to identify the specific genotypes and where it comes from.
Elizabeth: I’m going to go out on a limb here and predict that this sewage surveillance strategy is going to be employed all over the world. They have noted in this paper that they have improved techniques that render it a good deal more cost effective to do that, even in places that have fewer resources. I think it’s also going to teach us something about evolution of viruses.
Rick: Absolutely. As you mentioned, the method is now sensitive, it’s flexible, and it’s relatively inexpensive as well.
Elizabeth: Let us turn then to the New England Journal of Medicine. We were talking before we started to record about how infrequently this journal talks about dietary interventions. In this case, does your diet quality, if a change in that takes place, impact your mortality? [Editors’ Note: This study originally published in 2017.]
Rick: The investigators here noted there are really very few studies that have evaluated the relationship between changes in diet quality over time and the risk of death. They had two large populations in which they were able to do that, both health professionals — the Women and Nurses’ Health Study, which has about almost 50,000 women in it, and over 25,000 men in the Health Professionals Follow-Up Study.
Now, these were studies that were available from 1998 to 2010 where they collected data. We have looking at the health outcomes and with very specific dietary surveys. We can look at the change in diet quality over a 12-year period and then relate it to mortality.
Those that had an improvement in diet quality between a 13% to 33% improvement, we’ll talk about how they gauge that, as compared to those that had a relatively stable period, it resulted in about a 10% improvement in mortality.
There are different ways to gauge your diet, something called the Alternate Healthy Eating Index. There is an Alternate Mediterranean Diet score and DASH score. Essentially these things look at different food components.
But they do have some similarities in that they are all talking about using healthy foods that are high in vegetables, fruits, and legumes as well and less red meat and more fish. They tried to drill down into what were the specific causes of mortality that was improved. It was primarily cardiovascular mortality. There really wasn’t a very significant effect on cancer and very clear data that if you improve your diet over 12 years there is consistently a decreased risk of death associated with that.
Elizabeth: I think what’s really interesting to me about this study is that you can come to this game rather late — very similar in many respects to smoking cessation — and still reap benefits as a result of the change in behavior.
Rick: Absolutely. The two groups they used, the women were 30 to 55 years of age, and the men were 40 to 75 years of age. I’m going to call that middle age. Even changing your diet in middle age can improve your mortality.
By the way, it looks like there is a dose response curve, and that the people that had the greatest improvement in their diet had the greatest decrease in mortality. It’s up to a 17% decrease in mortality over the 12-year period.
Elizabeth: We seem to be talking a good deal more about nutrition — and, again, I’m going to go out on my prognostic limb here and say hyperprocessed foods are definitely getting an indictment. I am wondering how long it’s going to be before we start implementing taxation to reduce their consumption.
Rick: Yeah. I wish the message would get out on its own. If I told you that I could sell you a pill for nothing that would decrease mortality by 17%, gosh, I wouldn’t say we’d be rich, and this doesn’t cost any additional money.
Elizabeth: Well worth implementing for everybody.
Finally, let’s turn to this issue of maternal hypertensive disorder of pregnancy and mortality in offspring. This is in the BMJ. This looks at all those disorders of pregnancy that result in high blood pressure, but it looks at this outcome of, gosh, does this impact on your child’s mortality?
It took place in Denmark and, of course, we have already admired many times the robustness of their medical records. Over two million individuals born in Denmark alive between 1978 and 2018, with follow-up from date of birth until death, immigration, or the last day of December of 2018, whichever came first. The outcome was all-cause mortality and they also looked at 13 specific causes of death.
Among the moms in this study, they had 67,000-plus with preeclampsia, 679 with frank eclampsia, and just shy of 34,000 with hypertension. The one that was associated with the highest rate of death were women who had frank eclampsia. All of them, however, were associated with an increased risk of mortality. There were also increased risks among the moms who had an earlier onset and more severe conditions, and interestingly also an association with low education level on the part of the mom.
Rick: To put some numbers to that, Elizabeth, for mothers that had hypertension it increased the risk of perinatal death about 12%, preeclampsia it increased the risk to the child at 29%. For those with frank eclampsia, a 188% increase in mortality.
It looks like almost all that mortality takes place during the first year of life. This highlights to me that we need to make sure we prevent, diagnose, and begin to treat these conditions in the mother. Also to children born of these mothers, we need to evaluate them frequently knowing that they do have increased risk of death.
Elizabeth: Clearly, what this study does not show is the relationship between treatment and reduction in these adverse outcomes.
Rick: It doesn’t show the treatment has prevented death and you’d like to have a piece of data. This particular study doesn’t address it. You’re absolutely right.
Elizabeth: They do speculate, of course, about the potential mechanism by which this condition in the mom results in these adverse outcomes. They say there is a hypoxic ischemic environment during pregnancy — I guess that’s a reduction in the quality of the placenta — and that interaction plus abnormal inflammatory levels of various factors, and there are epigenetic changes that are associated with this.
Rick: You’re right. I mean, these placental changes may in and of itself be the cause. Or maybe, as you mentioned, the fact that it increases inflammation or it causes genetic, what we call, epigenetic changes. There are some biologically plausible mechanisms. The study results are pretty convincing.
Elizabeth: I would like to just get your comment on the fact that we know that increased risk of hypertension as seen with increasing maternal obesity. We are certainly seeing an increase in that worldwide.
Rick: Right. When I talked about preventing the hypertensive conditions in mothers, there are two things we know that can decrease that risk. One is controlling the body weight and the other would be physical activity, and I think obviously receiving good prenatal care.
Elizabeth: 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.