'Southern Diet' and Hypertension; Water and UTIs: It's PodMed Double T!



This week's topics include preventing fractures in those with osteopenia, the obesity trajectory from childhood, risk factors for hypertension in blacks, and water and recurrent bladder infection.

Program notes:

0:45 Water consumption and recurrent bladder infection

1:41 Fifty percent reduction in recurrence

2:51 Factors related to hypertension in blacks

3:50 Fried foods, sugar-sweetened beverages

4:50 Modifiable risk factors

5:43 Obesity in childhood and risk

6:44 Age five obesity predicts adolescent obesity

7:43 Women with osteopenia and zoledronate

8:43 Both vertebral and non-vertebral fractures lower

9:47 Did recommend vitamin D

10:43 End


Elizabeth Tracey: Can we help older women avoid osteoporosis?

Rick Lange, MD: Does drinking more water prevent recurrent bladder infections?

Elizabeth: What are the factors that are related to high blood pressure in African Americans?

Rick: And determining risk for childhood obesity.

Elizabeth: That's what we're talking about this week on PodMed TT, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I'm Elizabeth Tracey, a medical journalist at Johns Hopkins, and this will be posted on October 5th, 2018.

Rick: And I'm Rick Lange, President of Texas Tech University Health Sciences Center in El Paso, where I'm also Dean of the Paul L. Foster School of Medicine.

Elizabeth: Rick, I think since you changed up on us with some of the studies we were talking about covering this week, we should turn right to JAMA Internal Medicine, a look at whether drinking more water can help women avoid recurrent bladder infections or cystitis.

Rick: Thanks for the definition, because most people won't know what cystitis means. About 50% of women are going to have cystitis or bladder infections some time during their life, and the interesting thing is if you had a bladder infection, the chance of it recurring in the next year is about 25% to 30%. Now there's this old -- I don't want to call it a wives' tale -- but it's this historical story that if you drink more water it can actually prevent bladder infections, so that's what this study attempted to examine.

They took 140 premenopausal women that had bladder infection previously, not actively, and then they randomized them to just their routine diet, their routine drinking habits, or supplementing it with 1.5 extra liters of water per day. Essentially, that's a bottle of water three times a day.

They followed the women over the course of the year. The women that drank the extra water had a 50% reduction in recurrent bladder infection. Furthermore, they were less likely to require antibiotic treatments, and then when they did develop bladder infection, they developed it much later, almost twice as long as the women that didn't drink extra water. So the story you've heard -- drinking more water can prevent recurring bladder infections -- it appears there's a lot of truth to that.

Elizabeth: This, of course, is something that's very, very troubling for many women, this UTI, urinary tract infection. And you already segued kind of into this idea of treatment. Some of the antibiotics that are used for this are problematic.

Rick: In fact, it's estimated that 15% of all antibiotic prescriptions are for bladder infections, and we've talked before about how the persistent or continued use of antibiotics results in antibiotic resistance. The World Health Organization is looking for non-antibiotic ways to treat or prevent bladder infections, and it looks like water is.

Elizabeth: For all of us, then, who disparage those who walk around with those water bottles that they refill all over the place, we should probably be applauding them for a multitude of reasons. I think we're going to stay in that American Medical Association group and we're going to turn to the Journal of the American Medical Association.

For such a long time, we've noticed, of course, that there's a much higher rate of high blood pressure, or hypertension, among U.S. blacks than among other ethnic groups. And this study, I thought, was really interesting. It's a longitudinal cohort study of over 30,000 participants who did not have high blood pressure at baseline, and they were recruited between 2003 and 2007, and they participated in a follow-up visit about just short of 10 years later.

They looked at 12 clinical and social factors, including something that they called "Southern diet" to take a look at, "Wow! OK, where are you in this?" And of this number, just shy of 7,000 participants were included in this particular analysis. This thing that was identified as the Southern diet and that included a lot of fried foods, organ meats, sugar-sweetened beverages, bread. That was the absolute Number One factor that was significantly associated with higher hypertension in men and in women and is absolutely something that's modifiable.

So ... I think this is a really good news study because this is very troubling, this rate of high blood pressure among blacks. It leads to lots of things down the road, kidney failure, all kinds of stuff, and this is a modifiable risk factor.

Rick: I'm glad the way you teed it up because this was a study that looked at why blacks have an excess risk of hypertension compared to whites. You didn't put a number to it, but this study estimated that 52% of that reason was due to the Southern diet. The second most common contributing factor was a diet that was high in sodium compared to potassium. Again, that's modifiable as well. And then in women, excess weight or waist circumference also increased the risk. Again, these are all modifiable risk factors, so if we want to decrease the risk of hypertension and the consequent stroke and heart disease and kidney disease, these are things that we can do without prescribing medications.

Elizabeth: And all of these, of course, are linked -- the consumption of that diet, which is high in sodium and leads to a greater BMI [body mass index] for most people. I, at least, am really thankful for this study and this identification of this factor because we've talked about this so many times. Is there some genetic basis where we see this particular increased risk for hypertension and all the constellation of things that follow that? This study seems to suggest that no, there really isn't.

Rick: It clearly tells us that a lot of this is actually within our control. I agree with you -- rather than throwing up our hands and saying, "The risk of hypertension is higher in black individuals. We just need to accept it" -- no, no, no, these are modifiable risk factors and we need to address them.

Elizabeth: Your next one, then, sir, taking a look... we were just talking about obesity. In this case, in the New England Journal of Medicine, childhood obesity and what that means over the long haul.

Rick: On the basis of a large population, a longitudinal study of over 51,000 adolescents, they were able to do both a prospective and retrospective study looking back to say, "OK, did these adolescents who were obese, were they obese in childhood? If so, was that at a certain age period and can we use that to predict who will be obese as an adolescent?"

Here's what they determined. The overwhelming majority of normal-weight adolescents had a normal BMI at 1 and 2 years of age. That remained that way throughout childhood. However, approximately half of obese adolescents had actually become overweight obese by 5 years of age. In fact, when you look at that period between 2 and about 5 and 6 years of age, those that had an increase in their BMI, they call that a rebound adiposity. I'll mention why that is. They were much more likely to be obese. In fact, if you were obese at age 5 or 6, 90% of them were obese in adolescence.

This rebound adiposity, what happens is when an infant is born, it has about 10% or 14%, 15% fat by body weight. Then, as you know, up to about 6 or 12 months of age, they gain more fat. They become plump, but then it begins to trail off. Infants that have a rebound adiposity, that is they gain more weight between ages 2 and 6, those are the ones that are more likely to develop obesity as an adolescent.

Elizabeth: Clearly, however, children are interacting with the health care system during those ages, especially right before they get to school. So again, as we've talked about, it suggests to me that this is an opportunity where pediatricians can say, "Hmm, looks like we're on a trajectory that we really need to get our arms around."

Rick: It needs to start in preschool. Nutritional counseling needs to begin for the parent as soon as we've identified obese parents, because we know that increases the risk of childhood obesity as well.

Elizabeth: Well, that can be done even in pregnancy, usually.

Rick: Absolutely.

Elizabeth: OK. Finally, let's turn to our last one, the other end of the age spectrum. This is taking a look at women who have osteopenia, so not frank osteoporosis, but osteopenia. Wow! They've got less mineral deposits in their bones, and therefore at risk for developing frank osteoporosis and increase their fracture risk. Can the drug that's called zoledronate help in these people in preventing frank osteoporosis?

So they took a look at 2,000 women who had osteopenia and were 65 years of age or older, followed them for 6 years. They were randomly assigned to receive either four infusions of zoledronate at a dose of 5 milligrams, or normal saline, at 18-month intervals. So I kind of like this because they just have to take an infusion. They don't have to continue to take a daily medication. They also advised them to take a dietary calcium intake of 1 gram per day, but they did not provide calcium supplements and basically found that the risk of both non-vertebral and vertebral fragility fractures was significantly lower in those women who had received the bisphosphonate, which is what zoledronate falls into, than women who only got the placebo.

Rick: So Elizabeth, if I ask you the women who have fragility fractures, are they more likely to have osteoporosis or osteopenia? Most people would say, "Osteoporosis," because that's what we hear about. Actually, the number of women with osteopenia is much larger than the number of women with osteoporosis, so that's the group that's more likely to have fractures. So this study is a terrific study in that it says that we can take those individuals, and by giving them an infusion once every 18 months, reduce the risk of those fractures by between 30% and 40%. That's a significant benefit.

Elizabeth: I thought the other aspects of the study that were kind of interesting were the fact that they recommended calcium supplements, but did not provide them. Of course, we're seeing lots of plus-minus information about supplementation with calcium now, especially with regard to heart disease risk, and then also the vitamin D supplementation.

Rick: They didn't recommend calcium. They said, "Just make sure you have a good diet." But they did recommend vitamin D for women that weren't taking it. We've talked before about the fact that calcium really doesn't prevent bony fractures or osteoporosis. It's the vitamin D that does in older individuals.

Elizabeth: We're also spending an awful lot of time talking about vitamin D and vitamin D supplementation.

Rick: Vitamin D can be helpful, particularly in those that have vitamin D levels are low in both men and women. If women with osteopenia want to prevent fractures, this is the agent they should use, not a different agent.

Elizabeth: My caveat would also be to get vitamin D levels tested before taking a supplement.

Rick: I think that's not bad advice.

Elizabeth: On that note, I'm going to talk about the dietary factors and hypertension this week on the blog. 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.